Auto merge of #93069 - matthiaskrgr:rollup-gx1vkp7, r=matthiaskrgr

Rollup of 10 pull requests

Successful merges:

 - #88642 (Formally implement let chains)
 - #89621 (doc: guarantee call order for sort_by_cached_key)
 - #91278 (Use iterator instead of recursion in `codegen_place`)
 - #92124 (Little improves in CString `new` when creating from slice)
 - #92783 (Annotate dead code lint with notes about ignored derived impls)
 - #92797 (Remove horizontal lines at top of page)
 - #92920 (Move expr- and item-related pretty printing functions to modules)
 - #93041 (Remove some unused ordering derivations based on `DefId`)
 - #93051 (Add Option::is_some_with and Result::is_{ok,err}_with)
 - #93062 (Update books)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

54 files changed, 2041 insertions, 1683 deletions

diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index 470e9114217..6c172d59f83 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -392,14 +392,20 @@ impl<'hir> LoweringContext<'_, 'hir> {
     // If `cond` kind is `let`, returns `let`. Otherwise, wraps and returns `cond`
     // in a temporary block.
     fn manage_let_cond(&mut self, cond: &'hir hir::Expr<'hir>) -> &'hir hir::Expr<'hir> {
-        match cond.kind {
-            hir::ExprKind::Let(..) => cond,
-            _ => {
-                let span_block =
-                    self.mark_span_with_reason(DesugaringKind::CondTemporary, cond.span, None);
-                self.expr_drop_temps(span_block, cond, AttrVec::new())
+        fn has_let_expr<'hir>(expr: &'hir hir::Expr<'hir>) -> bool {
+            match expr.kind {
+                hir::ExprKind::Binary(_, lhs, rhs) => has_let_expr(lhs) || has_let_expr(rhs),
+                hir::ExprKind::Let(..) => true,
+                _ => false,
             }
         }
+        if has_let_expr(cond) {
+            cond
+        } else {
+            let reason = DesugaringKind::CondTemporary;
+            let span_block = self.mark_span_with_reason(reason, cond.span, None);
+            self.expr_drop_temps(span_block, cond, AttrVec::new())
+        }
     }
 
     // We desugar: `'label: while $cond $body` into:
diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs
index 89671788255..a6ecfa45206 100644
--- a/compiler/rustc_ast_passes/src/feature_gate.rs
+++ b/compiler/rustc_ast_passes/src/feature_gate.rs
@@ -707,11 +707,7 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session) {
         "`if let` guards are experimental",
         "you can write `if matches!(<expr>, <pattern>)` instead of `if let <pattern> = <expr>`"
     );
-    gate_all!(
-        let_chains,
-        "`let` expressions in this position are experimental",
-        "you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`"
-    );
+    gate_all!(let_chains, "`let` expressions in this position are unstable");
     gate_all!(
         async_closure,
         "async closures are unstable",
diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
index 17941058ed6..487451466f1 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -1,3 +1,6 @@
+mod expr;
+mod item;
+
 use crate::pp::Breaks::{Consistent, Inconsistent};
 use crate::pp::{self, Breaks};
 
@@ -6,10 +9,10 @@ use rustc_ast::token::{self, BinOpToken, CommentKind, DelimToken, Nonterminal, T
 use rustc_ast::tokenstream::{TokenStream, TokenTree};
 use rustc_ast::util::classify;
 use rustc_ast::util::comments::{gather_comments, Comment, CommentStyle};
-use rustc_ast::util::parser::{self, AssocOp, Fixity};
+use rustc_ast::util::parser;
 use rustc_ast::{self as ast, BlockCheckMode, PatKind, RangeEnd, RangeSyntax};
 use rustc_ast::{attr, Term};
-use rustc_ast::{GenericArg, MacArgs, ModKind};
+use rustc_ast::{GenericArg, MacArgs};
 use rustc_ast::{GenericBound, SelfKind, TraitBoundModifier};
 use rustc_ast::{InlineAsmOperand, InlineAsmRegOrRegClass};
 use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
@@ -210,10 +213,6 @@ pub fn literal_to_string(lit: token::Lit) -> String {
     out
 }
 
-fn visibility_qualified(vis: &ast::Visibility, s: &str) -> String {
-    format!("{}{}", State::to_string(|s| s.print_visibility(vis)), s)
-}
-
 impl std::ops::Deref for State<'_> {
     type Target = pp::Printer;
     fn deref(&self) -> &Self::Target {
@@ -938,13 +937,6 @@ impl<'a> State<'a> {
         self.commasep_cmnt(b, exprs, |s, e| s.print_expr(e), |e| e.span)
     }
 
-    crate fn print_foreign_mod(&mut self, nmod: &ast::ForeignMod, attrs: &[ast::Attribute]) {
-        self.print_inner_attributes(attrs);
-        for item in &nmod.items {
-            self.print_foreign_item(item);
-        }
-    }
-
     pub fn print_opt_lifetime(&mut self, lifetime: &Option<ast::Lifetime>) {
         if let Some(lt) = *lifetime {
             self.print_lifetime(lt);
@@ -1057,343 +1049,6 @@ impl<'a> State<'a> {
         self.end();
     }
 
-    crate fn print_foreign_item(&mut self, item: &ast::ForeignItem) {
-        let ast::Item { id, span, ident, ref attrs, ref kind, ref vis, tokens: _ } = *item;
-        self.ann.pre(self, AnnNode::SubItem(id));
-        self.hardbreak_if_not_bol();
-        self.maybe_print_comment(span.lo());
-        self.print_outer_attributes(attrs);
-        match kind {
-            ast::ForeignItemKind::Fn(box ast::Fn { defaultness, sig, generics, body }) => {
-                self.print_fn_full(sig, ident, generics, vis, *defaultness, body.as_deref(), attrs);
-            }
-            ast::ForeignItemKind::Static(ty, mutbl, body) => {
-                let def = ast::Defaultness::Final;
-                self.print_item_const(ident, Some(*mutbl), ty, body.as_deref(), vis, def);
-            }
-            ast::ForeignItemKind::TyAlias(box ast::TyAlias {
-                defaultness,
-                generics,
-                bounds,
-                ty,
-            }) => {
-                self.print_associated_type(
-                    ident,
-                    generics,
-                    bounds,
-                    ty.as_deref(),
-                    vis,
-                    *defaultness,
-                );
-            }
-            ast::ForeignItemKind::MacCall(m) => {
-                self.print_mac(m);
-                if m.args.need_semicolon() {
-                    self.word(";");
-                }
-            }
-        }
-        self.ann.post(self, AnnNode::SubItem(id))
-    }
-
-    fn print_item_const(
-        &mut self,
-        ident: Ident,
-        mutbl: Option<ast::Mutability>,
-        ty: &ast::Ty,
-        body: Option<&ast::Expr>,
-        vis: &ast::Visibility,
-        defaultness: ast::Defaultness,
-    ) {
-        self.head("");
-        self.print_visibility(vis);
-        self.print_defaultness(defaultness);
-        let leading = match mutbl {
-            None => "const",
-            Some(ast::Mutability::Not) => "static",
-            Some(ast::Mutability::Mut) => "static mut",
-        };
-        self.word_space(leading);
-        self.print_ident(ident);
-        self.word_space(":");
-        self.print_type(ty);
-        if body.is_some() {
-            self.space();
-        }
-        self.end(); // end the head-ibox
-        if let Some(body) = body {
-            self.word_space("=");
-            self.print_expr(body);
-        }
-        self.word(";");
-        self.end(); // end the outer cbox
-    }
-
-    fn print_associated_type(
-        &mut self,
-        ident: Ident,
-        generics: &ast::Generics,
-        bounds: &ast::GenericBounds,
-        ty: Option<&ast::Ty>,
-        vis: &ast::Visibility,
-        defaultness: ast::Defaultness,
-    ) {
-        self.head("");
-        self.print_visibility(vis);
-        self.print_defaultness(defaultness);
-        self.word_space("type");
-        self.print_ident(ident);
-        self.print_generic_params(&generics.params);
-        self.print_type_bounds(":", bounds);
-        self.print_where_clause(&generics.where_clause);
-        if let Some(ty) = ty {
-            self.space();
-            self.word_space("=");
-            self.print_type(ty);
-        }
-        self.word(";");
-        self.end(); // end inner head-block
-        self.end(); // end outer head-block
-    }
-
-    /// Pretty-prints an item.
-    crate fn print_item(&mut self, item: &ast::Item) {
-        self.hardbreak_if_not_bol();
-        self.maybe_print_comment(item.span.lo());
-        self.print_outer_attributes(&item.attrs);
-        self.ann.pre(self, AnnNode::Item(item));
-        match item.kind {
-            ast::ItemKind::ExternCrate(orig_name) => {
-                self.head(visibility_qualified(&item.vis, "extern crate"));
-                if let Some(orig_name) = orig_name {
-                    self.print_name(orig_name);
-                    self.space();
-                    self.word("as");
-                    self.space();
-                }
-                self.print_ident(item.ident);
-                self.word(";");
-                self.end(); // end inner head-block
-                self.end(); // end outer head-block
-            }
-            ast::ItemKind::Use(ref tree) => {
-                self.head(visibility_qualified(&item.vis, "use"));
-                self.print_use_tree(tree);
-                self.word(";");
-                self.end(); // end inner head-block
-                self.end(); // end outer head-block
-            }
-            ast::ItemKind::Static(ref ty, mutbl, ref body) => {
-                let def = ast::Defaultness::Final;
-                self.print_item_const(item.ident, Some(mutbl), ty, body.as_deref(), &item.vis, def);
-            }
-            ast::ItemKind::Const(def, ref ty, ref body) => {
-                self.print_item_const(item.ident, None, ty, body.as_deref(), &item.vis, def);
-            }
-            ast::ItemKind::Fn(box ast::Fn { defaultness, ref sig, ref generics, ref body }) => {
-                let body = body.as_deref();
-                self.print_fn_full(
-                    sig,
-                    item.ident,
-                    generics,
-                    &item.vis,
-                    defaultness,
-                    body,
-                    &item.attrs,
-                );
-            }
-            ast::ItemKind::Mod(unsafety, ref mod_kind) => {
-                self.head(Self::to_string(|s| {
-                    s.print_visibility(&item.vis);
-                    s.print_unsafety(unsafety);
-                    s.word("mod");
-                }));
-                self.print_ident(item.ident);
-
-                match mod_kind {
-                    ModKind::Loaded(items, ..) => {
-                        self.nbsp();
-                        self.bopen();
-                        self.print_inner_attributes(&item.attrs);
-                        for item in items {
-                            self.print_item(item);
-                        }
-                        let empty = item.attrs.is_empty() && items.is_empty();
-                        self.bclose(item.span, empty);
-                    }
-                    ModKind::Unloaded => {
-                        self.word(";");
-                        self.end(); // end inner head-block
-                        self.end(); // end outer head-block
-                    }
-                }
-            }
-            ast::ItemKind::ForeignMod(ref nmod) => {
-                self.head(Self::to_string(|s| {
-                    s.print_unsafety(nmod.unsafety);
-                    s.word("extern");
-                }));
-                if let Some(abi) = nmod.abi {
-                    self.print_literal(&abi.as_lit());
-                    self.nbsp();
-                }
-                self.bopen();
-                self.print_foreign_mod(nmod, &item.attrs);
-                let empty = item.attrs.is_empty() && nmod.items.is_empty();
-                self.bclose(item.span, empty);
-            }
-            ast::ItemKind::GlobalAsm(ref asm) => {
-                self.head(visibility_qualified(&item.vis, "global_asm!"));
-                self.print_inline_asm(asm);
-                self.end();
-            }
-            ast::ItemKind::TyAlias(box ast::TyAlias {
-                defaultness,
-                ref generics,
-                ref bounds,
-                ref ty,
-            }) => {
-                let ty = ty.as_deref();
-                self.print_associated_type(
-                    item.ident,
-                    generics,
-                    bounds,
-                    ty,
-                    &item.vis,
-                    defaultness,
-                );
-            }
-            ast::ItemKind::Enum(ref enum_definition, ref params) => {
-                self.print_enum_def(enum_definition, params, item.ident, item.span, &item.vis);
-            }
-            ast::ItemKind::Struct(ref struct_def, ref generics) => {
-                self.head(visibility_qualified(&item.vis, "struct"));
-                self.print_struct(struct_def, generics, item.ident, item.span, true);
-            }
-            ast::ItemKind::Union(ref struct_def, ref generics) => {
-                self.head(visibility_qualified(&item.vis, "union"));
-                self.print_struct(struct_def, generics, item.ident, item.span, true);
-            }
-            ast::ItemKind::Impl(box ast::Impl {
-                unsafety,
-                polarity,
-                defaultness,
-                constness,
-                ref generics,
-                ref of_trait,
-                ref self_ty,
-                ref items,
-            }) => {
-                self.head("");
-                self.print_visibility(&item.vis);
-                self.print_defaultness(defaultness);
-                self.print_unsafety(unsafety);
-                self.word("impl");
-
-                if generics.params.is_empty() {
-                    self.nbsp();
-                } else {
-                    self.print_generic_params(&generics.params);
-                    self.space();
-                }
-
-                self.print_constness(constness);
-
-                if let ast::ImplPolarity::Negative(_) = polarity {
-                    self.word("!");
-                }
-
-                if let Some(ref t) = *of_trait {
-                    self.print_trait_ref(t);
-                    self.space();
-                    self.word_space("for");
-                }
-
-                self.print_type(self_ty);
-                self.print_where_clause(&generics.where_clause);
-
-                self.space();
-                self.bopen();
-                self.print_inner_attributes(&item.attrs);
-                for impl_item in items {
-                    self.print_assoc_item(impl_item);
-                }
-                let empty = item.attrs.is_empty() && items.is_empty();
-                self.bclose(item.span, empty);
-            }
-            ast::ItemKind::Trait(box ast::Trait {
-                is_auto,
-                unsafety,
-                ref generics,
-                ref bounds,
-                ref items,
-                ..
-            }) => {
-                self.head("");
-                self.print_visibility(&item.vis);
-                self.print_unsafety(unsafety);
-                self.print_is_auto(is_auto);
-                self.word_nbsp("trait");
-                self.print_ident(item.ident);
-                self.print_generic_params(&generics.params);
-                let mut real_bounds = Vec::with_capacity(bounds.len());
-                for b in bounds.iter() {
-                    if let GenericBound::Trait(ref ptr, ast::TraitBoundModifier::Maybe) = *b {
-                        self.space();
-                        self.word_space("for ?");
-                        self.print_trait_ref(&ptr.trait_ref);
-                    } else {
-                        real_bounds.push(b.clone());
-                    }
-                }
-                self.print_type_bounds(":", &real_bounds);
-                self.print_where_clause(&generics.where_clause);
-                self.word(" ");
-                self.bopen();
-                self.print_inner_attributes(&item.attrs);
-                for trait_item in items {
-                    self.print_assoc_item(trait_item);
-                }
-                let empty = item.attrs.is_empty() && items.is_empty();
-                self.bclose(item.span, empty);
-            }
-            ast::ItemKind::TraitAlias(ref generics, ref bounds) => {
-                self.head(visibility_qualified(&item.vis, "trait"));
-                self.print_ident(item.ident);
-                self.print_generic_params(&generics.params);
-                let mut real_bounds = Vec::with_capacity(bounds.len());
-                // FIXME(durka) this seems to be some quite outdated syntax
-                for b in bounds.iter() {
-                    if let GenericBound::Trait(ref ptr, ast::TraitBoundModifier::Maybe) = *b {
-                        self.space();
-                        self.word_space("for ?");
-                        self.print_trait_ref(&ptr.trait_ref);
-                    } else {
-                        real_bounds.push(b.clone());
-                    }
-                }
-                self.nbsp();
-                self.print_type_bounds("=", &real_bounds);
-                self.print_where_clause(&generics.where_clause);
-                self.word(";");
-                self.end(); // end inner head-block
-                self.end(); // end outer head-block
-            }
-            ast::ItemKind::MacCall(ref mac) => {
-                self.print_mac(mac);
-                if mac.args.need_semicolon() {
-                    self.word(";");
-                }
-            }
-            ast::ItemKind::MacroDef(ref macro_def) => {
-                self.print_mac_def(macro_def, &item.ident, &item.span, |state| {
-                    state.print_visibility(&item.vis)
-                });
-            }
-        }
-        self.ann.post(self, AnnNode::Item(item))
-    }
-
     fn print_trait_ref(&mut self, t: &ast::TraitRef) {
         self.print_path(&t.path, false, 0)
     }
@@ -1411,167 +1066,6 @@ impl<'a> State<'a> {
         self.print_trait_ref(&t.trait_ref)
     }
 
-    crate fn print_enum_def(
-        &mut self,
-        enum_definition: &ast::EnumDef,
-        generics: &ast::Generics,
-        ident: Ident,
-        span: rustc_span::Span,
-        visibility: &ast::Visibility,
-    ) {
-        self.head(visibility_qualified(visibility, "enum"));
-        self.print_ident(ident);
-        self.print_generic_params(&generics.params);
-        self.print_where_clause(&generics.where_clause);
-        self.space();
-        self.print_variants(&enum_definition.variants, span)
-    }
-
-    crate fn print_variants(&mut self, variants: &[ast::Variant], span: rustc_span::Span) {
-        self.bopen();
-        for v in variants {
-            self.space_if_not_bol();
-            self.maybe_print_comment(v.span.lo());
-            self.print_outer_attributes(&v.attrs);
-            self.ibox(INDENT_UNIT);
-            self.print_variant(v);
-            self.word(",");
-            self.end();
-            self.maybe_print_trailing_comment(v.span, None);
-        }
-        let empty = variants.is_empty();
-        self.bclose(span, empty)
-    }
-
-    crate fn print_visibility(&mut self, vis: &ast::Visibility) {
-        match vis.kind {
-            ast::VisibilityKind::Public => self.word_nbsp("pub"),
-            ast::VisibilityKind::Crate(sugar) => match sugar {
-                ast::CrateSugar::PubCrate => self.word_nbsp("pub(crate)"),
-                ast::CrateSugar::JustCrate => self.word_nbsp("crate"),
-            },
-            ast::VisibilityKind::Restricted { ref path, .. } => {
-                let path = Self::to_string(|s| s.print_path(path, false, 0));
-                if path == "self" || path == "super" {
-                    self.word_nbsp(format!("pub({})", path))
-                } else {
-                    self.word_nbsp(format!("pub(in {})", path))
-                }
-            }
-            ast::VisibilityKind::Inherited => {}
-        }
-    }
-
-    crate fn print_defaultness(&mut self, defaultness: ast::Defaultness) {
-        if let ast::Defaultness::Default(_) = defaultness {
-            self.word_nbsp("default");
-        }
-    }
-
-    crate fn print_record_struct_body(&mut self, fields: &[ast::FieldDef], span: rustc_span::Span) {
-        self.nbsp();
-        self.bopen();
-
-        let empty = fields.is_empty();
-        if !empty {
-            self.hardbreak_if_not_bol();
-
-            for field in fields {
-                self.hardbreak_if_not_bol();
-                self.maybe_print_comment(field.span.lo());
-                self.print_outer_attributes(&field.attrs);
-                self.print_visibility(&field.vis);
-                self.print_ident(field.ident.unwrap());
-                self.word_nbsp(":");
-                self.print_type(&field.ty);
-                self.word(",");
-            }
-        }
-
-        self.bclose(span, empty);
-    }
-
-    crate fn print_struct(
-        &mut self,
-        struct_def: &ast::VariantData,
-        generics: &ast::Generics,
-        ident: Ident,
-        span: rustc_span::Span,
-        print_finalizer: bool,
-    ) {
-        self.print_ident(ident);
-        self.print_generic_params(&generics.params);
-        match struct_def {
-            ast::VariantData::Tuple(..) | ast::VariantData::Unit(..) => {
-                if let ast::VariantData::Tuple(..) = struct_def {
-                    self.popen();
-                    self.commasep(Inconsistent, struct_def.fields(), |s, field| {
-                        s.maybe_print_comment(field.span.lo());
-                        s.print_outer_attributes(&field.attrs);
-                        s.print_visibility(&field.vis);
-                        s.print_type(&field.ty)
-                    });
-                    self.pclose();
-                }
-                self.print_where_clause(&generics.where_clause);
-                if print_finalizer {
-                    self.word(";");
-                }
-                self.end();
-                self.end(); // Close the outer-box.
-            }
-            ast::VariantData::Struct(ref fields, ..) => {
-                self.print_where_clause(&generics.where_clause);
-                self.print_record_struct_body(fields, span);
-            }
-        }
-    }
-
-    crate fn print_variant(&mut self, v: &ast::Variant) {
-        self.head("");
-        self.print_visibility(&v.vis);
-        let generics = ast::Generics::default();
-        self.print_struct(&v.data, &generics, v.ident, v.span, false);
-        if let Some(ref d) = v.disr_expr {
-            self.space();
-            self.word_space("=");
-            self.print_expr(&d.value)
-        }
-    }
-
-    crate fn print_assoc_item(&mut self, item: &ast::AssocItem) {
-        let ast::Item { id, span, ident, ref attrs, ref kind, ref vis, tokens: _ } = *item;
-        self.ann.pre(self, AnnNode::SubItem(id));
-        self.hardbreak_if_not_bol();
-        self.maybe_print_comment(span.lo());
-        self.print_outer_attributes(attrs);
-        match kind {
-            ast::AssocItemKind::Fn(box ast::Fn { defaultness, sig, generics, body }) => {
-                self.print_fn_full(sig, ident, generics, vis, *defaultness, body.as_deref(), attrs);
-            }
-            ast::AssocItemKind::Const(def, ty, body) => {
-                self.print_item_const(ident, None, ty, body.as_deref(), vis, *def);
-            }
-            ast::AssocItemKind::TyAlias(box ast::TyAlias { defaultness, generics, bounds, ty }) => {
-                self.print_associated_type(
-                    ident,
-                    generics,
-                    bounds,
-                    ty.as_deref(),
-                    vis,
-                    *defaultness,
-                );
-            }
-            ast::AssocItemKind::MacCall(m) => {
-                self.print_mac(m);
-                if m.args.need_semicolon() {
-                    self.word(";");
-                }
-            }
-        }
-        self.ann.post(self, AnnNode::SubItem(id))
-    }
-
     crate fn print_stmt(&mut self, st: &ast::Stmt) {
         self.maybe_print_comment(st.span.lo());
         match st.kind {
@@ -1682,42 +1176,6 @@ impl<'a> State<'a> {
         self.print_expr_cond_paren(expr, Self::cond_needs_par(expr) || npals())
     }
 
-    fn print_else(&mut self, els: Option<&ast::Expr>) {
-        if let Some(_else) = els {
-            match _else.kind {
-                // Another `else if` block.
-                ast::ExprKind::If(ref i, ref then, ref e) => {
-                    self.cbox(INDENT_UNIT - 1);
-                    self.ibox(0);
-                    self.word(" else if ");
-                    self.print_expr_as_cond(i);
-                    self.space();
-                    self.print_block(then);
-                    self.print_else(e.as_deref())
-                }
-                // Final `else` block.
-                ast::ExprKind::Block(ref b, _) => {
-                    self.cbox(INDENT_UNIT - 1);
-                    self.ibox(0);
-                    self.word(" else ");
-                    self.print_block(b)
-                }
-                // Constraints would be great here!
-                _ => {
-                    panic!("print_if saw if with weird alternative");
-                }
-            }
-        }
-    }
-
-    crate fn print_if(&mut self, test: &ast::Expr, blk: &ast::Block, elseopt: Option<&ast::Expr>) {
-        self.head("if");
-        self.print_expr_as_cond(test);
-        self.space();
-        self.print_block(blk);
-        self.print_else(elseopt)
-    }
-
     crate fn print_mac(&mut self, m: &ast::MacCall) {
         self.print_mac_common(
             Some(MacHeader::Path(&m.path)),
@@ -1730,477 +1188,6 @@ impl<'a> State<'a> {
         );
     }
 
-    fn print_call_post(&mut self, args: &[P<ast::Expr>]) {
-        self.popen();
-        self.commasep_exprs(Inconsistent, args);
-        self.pclose()
-    }
-
-    crate fn print_expr_maybe_paren(&mut self, expr: &ast::Expr, prec: i8) {
-        self.print_expr_cond_paren(expr, expr.precedence().order() < prec)
-    }
-
-    /// Prints an expr using syntax that's acceptable in a condition position, such as the `cond` in
-    /// `if cond { ... }`.
-    crate fn print_expr_as_cond(&mut self, expr: &ast::Expr) {
-        self.print_expr_cond_paren(expr, Self::cond_needs_par(expr))
-    }
-
-    // Does `expr` need parentheses when printed in a condition position?
-    //
-    // These cases need parens due to the parse error observed in #26461: `if return {}`
-    // parses as the erroneous construct `if (return {})`, not `if (return) {}`.
-    fn cond_needs_par(expr: &ast::Expr) -> bool {
-        match expr.kind {
-            ast::ExprKind::Break(..) | ast::ExprKind::Closure(..) | ast::ExprKind::Ret(..) => true,
-            _ => parser::contains_exterior_struct_lit(expr),
-        }
-    }
-
-    /// Prints `expr` or `(expr)` when `needs_par` holds.
-    fn print_expr_cond_paren(&mut self, expr: &ast::Expr, needs_par: bool) {
-        if needs_par {
-            self.popen();
-        }
-        self.print_expr(expr);
-        if needs_par {
-            self.pclose();
-        }
-    }
-
-    fn print_expr_vec(&mut self, exprs: &[P<ast::Expr>]) {
-        self.ibox(INDENT_UNIT);
-        self.word("[");
-        self.commasep_exprs(Inconsistent, exprs);
-        self.word("]");
-        self.end();
-    }
-
-    fn print_expr_anon_const(&mut self, expr: &ast::AnonConst) {
-        self.ibox(INDENT_UNIT);
-        self.word("const");
-        self.print_expr(&expr.value);
-        self.end();
-    }
-
-    fn print_expr_repeat(&mut self, element: &ast::Expr, count: &ast::AnonConst) {
-        self.ibox(INDENT_UNIT);
-        self.word("[");
-        self.print_expr(element);
-        self.word_space(";");
-        self.print_expr(&count.value);
-        self.word("]");
-        self.end();
-    }
-
-    fn print_expr_struct(
-        &mut self,
-        qself: &Option<ast::QSelf>,
-        path: &ast::Path,
-        fields: &[ast::ExprField],
-        rest: &ast::StructRest,
-    ) {
-        if let Some(qself) = qself {
-            self.print_qpath(path, qself, true);
-        } else {
-            self.print_path(path, true, 0);
-        }
-        self.word("{");
-        self.commasep_cmnt(
-            Consistent,
-            fields,
-            |s, field| {
-                s.print_outer_attributes(&field.attrs);
-                s.ibox(INDENT_UNIT);
-                if !field.is_shorthand {
-                    s.print_ident(field.ident);
-                    s.word_space(":");
-                }
-                s.print_expr(&field.expr);
-                s.end();
-            },
-            |f| f.span,
-        );
-        match rest {
-            ast::StructRest::Base(_) | ast::StructRest::Rest(_) => {
-                self.ibox(INDENT_UNIT);
-                if !fields.is_empty() {
-                    self.word(",");
-                    self.space();
-                }
-                self.word("..");
-                if let ast::StructRest::Base(ref expr) = *rest {
-                    self.print_expr(expr);
-                }
-                self.end();
-            }
-            ast::StructRest::None if !fields.is_empty() => self.word(","),
-            _ => {}
-        }
-        self.word("}");
-    }
-
-    fn print_expr_tup(&mut self, exprs: &[P<ast::Expr>]) {
-        self.popen();
-        self.commasep_exprs(Inconsistent, exprs);
-        if exprs.len() == 1 {
-            self.word(",");
-        }
-        self.pclose()
-    }
-
-    fn print_expr_call(&mut self, func: &ast::Expr, args: &[P<ast::Expr>]) {
-        let prec = match func.kind {
-            ast::ExprKind::Field(..) => parser::PREC_FORCE_PAREN,
-            _ => parser::PREC_POSTFIX,
-        };
-
-        self.print_expr_maybe_paren(func, prec);
-        self.print_call_post(args)
-    }
-
-    fn print_expr_method_call(&mut self, segment: &ast::PathSegment, args: &[P<ast::Expr>]) {
-        let base_args = &args[1..];
-        self.print_expr_maybe_paren(&args[0], parser::PREC_POSTFIX);
-        self.word(".");
-        self.print_ident(segment.ident);
-        if let Some(ref args) = segment.args {
-            self.print_generic_args(args, true);
-        }
-        self.print_call_post(base_args)
-    }
-
-    fn print_expr_binary(&mut self, op: ast::BinOp, lhs: &ast::Expr, rhs: &ast::Expr) {
-        let assoc_op = AssocOp::from_ast_binop(op.node);
-        let prec = assoc_op.precedence() as i8;
-        let fixity = assoc_op.fixity();
-
-        let (left_prec, right_prec) = match fixity {
-            Fixity::Left => (prec, prec + 1),
-            Fixity::Right => (prec + 1, prec),
-            Fixity::None => (prec + 1, prec + 1),
-        };
-
-        let left_prec = match (&lhs.kind, op.node) {
-            // These cases need parens: `x as i32 < y` has the parser thinking that `i32 < y` is
-            // the beginning of a path type. It starts trying to parse `x as (i32 < y ...` instead
-            // of `(x as i32) < ...`. We need to convince it _not_ to do that.
-            (&ast::ExprKind::Cast { .. }, ast::BinOpKind::Lt | ast::BinOpKind::Shl) => {
-                parser::PREC_FORCE_PAREN
-            }
-            // We are given `(let _ = a) OP b`.
-            //
-            // - When `OP <= LAnd` we should print `let _ = a OP b` to avoid redundant parens
-            //   as the parser will interpret this as `(let _ = a) OP b`.
-            //
-            // - Otherwise, e.g. when we have `(let a = b) < c` in AST,
-            //   parens are required since the parser would interpret `let a = b < c` as
-            //   `let a = (b < c)`. To achieve this, we force parens.
-            (&ast::ExprKind::Let { .. }, _) if !parser::needs_par_as_let_scrutinee(prec) => {
-                parser::PREC_FORCE_PAREN
-            }
-            _ => left_prec,
-        };
-
-        self.print_expr_maybe_paren(lhs, left_prec);
-        self.space();
-        self.word_space(op.node.to_string());
-        self.print_expr_maybe_paren(rhs, right_prec)
-    }
-
-    fn print_expr_unary(&mut self, op: ast::UnOp, expr: &ast::Expr) {
-        self.word(ast::UnOp::to_string(op));
-        self.print_expr_maybe_paren(expr, parser::PREC_PREFIX)
-    }
-
-    fn print_expr_addr_of(
-        &mut self,
-        kind: ast::BorrowKind,
-        mutability: ast::Mutability,
-        expr: &ast::Expr,
-    ) {
-        self.word("&");
-        match kind {
-            ast::BorrowKind::Ref => self.print_mutability(mutability, false),
-            ast::BorrowKind::Raw => {
-                self.word_nbsp("raw");
-                self.print_mutability(mutability, true);
-            }
-        }
-        self.print_expr_maybe_paren(expr, parser::PREC_PREFIX)
-    }
-
-    pub fn print_expr(&mut self, expr: &ast::Expr) {
-        self.print_expr_outer_attr_style(expr, true)
-    }
-
-    fn print_expr_outer_attr_style(&mut self, expr: &ast::Expr, is_inline: bool) {
-        self.maybe_print_comment(expr.span.lo());
-
-        let attrs = &expr.attrs;
-        if is_inline {
-            self.print_outer_attributes_inline(attrs);
-        } else {
-            self.print_outer_attributes(attrs);
-        }
-
-        self.ibox(INDENT_UNIT);
-        self.ann.pre(self, AnnNode::Expr(expr));
-        match expr.kind {
-            ast::ExprKind::Box(ref expr) => {
-                self.word_space("box");
-                self.print_expr_maybe_paren(expr, parser::PREC_PREFIX);
-            }
-            ast::ExprKind::Array(ref exprs) => {
-                self.print_expr_vec(exprs);
-            }
-            ast::ExprKind::ConstBlock(ref anon_const) => {
-                self.print_expr_anon_const(anon_const);
-            }
-            ast::ExprKind::Repeat(ref element, ref count) => {
-                self.print_expr_repeat(element, count);
-            }
-            ast::ExprKind::Struct(ref se) => {
-                self.print_expr_struct(&se.qself, &se.path, &se.fields, &se.rest);
-            }
-            ast::ExprKind::Tup(ref exprs) => {
-                self.print_expr_tup(exprs);
-            }
-            ast::ExprKind::Call(ref func, ref args) => {
-                self.print_expr_call(func, &args);
-            }
-            ast::ExprKind::MethodCall(ref segment, ref args, _) => {
-                self.print_expr_method_call(segment, &args);
-            }
-            ast::ExprKind::Binary(op, ref lhs, ref rhs) => {
-                self.print_expr_binary(op, lhs, rhs);
-            }
-            ast::ExprKind::Unary(op, ref expr) => {
-                self.print_expr_unary(op, expr);
-            }
-            ast::ExprKind::AddrOf(k, m, ref expr) => {
-                self.print_expr_addr_of(k, m, expr);
-            }
-            ast::ExprKind::Lit(ref lit) => {
-                self.print_literal(lit);
-            }
-            ast::ExprKind::Cast(ref expr, ref ty) => {
-                let prec = AssocOp::As.precedence() as i8;
-                self.print_expr_maybe_paren(expr, prec);
-                self.space();
-                self.word_space("as");
-                self.print_type(ty);
-            }
-            ast::ExprKind::Type(ref expr, ref ty) => {
-                let prec = AssocOp::Colon.precedence() as i8;
-                self.print_expr_maybe_paren(expr, prec);
-                self.word_space(":");
-                self.print_type(ty);
-            }
-            ast::ExprKind::Let(ref pat, ref scrutinee, _) => {
-                self.print_let(pat, scrutinee);
-            }
-            ast::ExprKind::If(ref test, ref blk, ref elseopt) => {
-                self.print_if(test, blk, elseopt.as_deref())
-            }
-            ast::ExprKind::While(ref test, ref blk, opt_label) => {
-                if let Some(label) = opt_label {
-                    self.print_ident(label.ident);
-                    self.word_space(":");
-                }
-                self.head("while");
-                self.print_expr_as_cond(test);
-                self.space();
-                self.print_block_with_attrs(blk, attrs);
-            }
-            ast::ExprKind::ForLoop(ref pat, ref iter, ref blk, opt_label) => {
-                if let Some(label) = opt_label {
-                    self.print_ident(label.ident);
-                    self.word_space(":");
-                }
-                self.head("for");
-                self.print_pat(pat);
-                self.space();
-                self.word_space("in");
-                self.print_expr_as_cond(iter);
-                self.space();
-                self.print_block_with_attrs(blk, attrs);
-            }
-            ast::ExprKind::Loop(ref blk, opt_label) => {
-                if let Some(label) = opt_label {
-                    self.print_ident(label.ident);
-                    self.word_space(":");
-                }
-                self.head("loop");
-                self.print_block_with_attrs(blk, attrs);
-            }
-            ast::ExprKind::Match(ref expr, ref arms) => {
-                self.cbox(INDENT_UNIT);
-                self.ibox(INDENT_UNIT);
-                self.word_nbsp("match");
-                self.print_expr_as_cond(expr);
-                self.space();
-                self.bopen();
-                self.print_inner_attributes_no_trailing_hardbreak(attrs);
-                for arm in arms {
-                    self.print_arm(arm);
-                }
-                let empty = attrs.is_empty() && arms.is_empty();
-                self.bclose(expr.span, empty);
-            }
-            ast::ExprKind::Closure(
-                capture_clause,
-                asyncness,
-                movability,
-                ref decl,
-                ref body,
-                _,
-            ) => {
-                self.print_movability(movability);
-                self.print_asyncness(asyncness);
-                self.print_capture_clause(capture_clause);
-
-                self.print_fn_params_and_ret(decl, true);
-                self.space();
-                self.print_expr(body);
-                self.end(); // need to close a box
-
-                // a box will be closed by print_expr, but we didn't want an overall
-                // wrapper so we closed the corresponding opening. so create an
-                // empty box to satisfy the close.
-                self.ibox(0);
-            }
-            ast::ExprKind::Block(ref blk, opt_label) => {
-                if let Some(label) = opt_label {
-                    self.print_ident(label.ident);
-                    self.word_space(":");
-                }
-                // containing cbox, will be closed by print-block at }
-                self.cbox(INDENT_UNIT);
-                // head-box, will be closed by print-block after {
-                self.ibox(0);
-                self.print_block_with_attrs(blk, attrs);
-            }
-            ast::ExprKind::Async(capture_clause, _, ref blk) => {
-                self.word_nbsp("async");
-                self.print_capture_clause(capture_clause);
-                // cbox/ibox in analogy to the `ExprKind::Block` arm above
-                self.cbox(INDENT_UNIT);
-                self.ibox(0);
-                self.print_block_with_attrs(blk, attrs);
-            }
-            ast::ExprKind::Await(ref expr) => {
-                self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
-                self.word(".await");
-            }
-            ast::ExprKind::Assign(ref lhs, ref rhs, _) => {
-                let prec = AssocOp::Assign.precedence() as i8;
-                self.print_expr_maybe_paren(lhs, prec + 1);
-                self.space();
-                self.word_space("=");
-                self.print_expr_maybe_paren(rhs, prec);
-            }
-            ast::ExprKind::AssignOp(op, ref lhs, ref rhs) => {
-                let prec = AssocOp::Assign.precedence() as i8;
-                self.print_expr_maybe_paren(lhs, prec + 1);
-                self.space();
-                self.word(op.node.to_string());
-                self.word_space("=");
-                self.print_expr_maybe_paren(rhs, prec);
-            }
-            ast::ExprKind::Field(ref expr, ident) => {
-                self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
-                self.word(".");
-                self.print_ident(ident);
-            }
-            ast::ExprKind::Index(ref expr, ref index) => {
-                self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
-                self.word("[");
-                self.print_expr(index);
-                self.word("]");
-            }
-            ast::ExprKind::Range(ref start, ref end, limits) => {
-                // Special case for `Range`.  `AssocOp` claims that `Range` has higher precedence
-                // than `Assign`, but `x .. x = x` gives a parse error instead of `x .. (x = x)`.
-                // Here we use a fake precedence value so that any child with lower precedence than
-                // a "normal" binop gets parenthesized.  (`LOr` is the lowest-precedence binop.)
-                let fake_prec = AssocOp::LOr.precedence() as i8;
-                if let Some(ref e) = *start {
-                    self.print_expr_maybe_paren(e, fake_prec);
-                }
-                if limits == ast::RangeLimits::HalfOpen {
-                    self.word("..");
-                } else {
-                    self.word("..=");
-                }
-                if let Some(ref e) = *end {
-                    self.print_expr_maybe_paren(e, fake_prec);
-                }
-            }
-            ast::ExprKind::Underscore => self.word("_"),
-            ast::ExprKind::Path(None, ref path) => self.print_path(path, true, 0),
-            ast::ExprKind::Path(Some(ref qself), ref path) => self.print_qpath(path, qself, true),
-            ast::ExprKind::Break(opt_label, ref opt_expr) => {
-                self.word("break");
-                if let Some(label) = opt_label {
-                    self.space();
-                    self.print_ident(label.ident);
-                }
-                if let Some(ref expr) = *opt_expr {
-                    self.space();
-                    self.print_expr_maybe_paren(expr, parser::PREC_JUMP);
-                }
-            }
-            ast::ExprKind::Continue(opt_label) => {
-                self.word("continue");
-                if let Some(label) = opt_label {
-                    self.space();
-                    self.print_ident(label.ident);
-                }
-            }
-            ast::ExprKind::Ret(ref result) => {
-                self.word("return");
-                if let Some(ref expr) = *result {
-                    self.word(" ");
-                    self.print_expr_maybe_paren(expr, parser::PREC_JUMP);
-                }
-            }
-            ast::ExprKind::InlineAsm(ref a) => {
-                self.word("asm!");
-                self.print_inline_asm(a);
-            }
-            ast::ExprKind::MacCall(ref m) => self.print_mac(m),
-            ast::ExprKind::Paren(ref e) => {
-                self.popen();
-                self.print_expr(e);
-                self.pclose();
-            }
-            ast::ExprKind::Yield(ref e) => {
-                self.word("yield");
-
-                if let Some(ref expr) = *e {
-                    self.space();
-                    self.print_expr_maybe_paren(expr, parser::PREC_JUMP);
-                }
-            }
-            ast::ExprKind::Try(ref e) => {
-                self.print_expr_maybe_paren(e, parser::PREC_POSTFIX);
-                self.word("?")
-            }
-            ast::ExprKind::TryBlock(ref blk) => {
-                self.head("try");
-                self.print_block_with_attrs(blk, attrs)
-            }
-            ast::ExprKind::Err => {
-                self.popen();
-                self.word("/*ERROR*/");
-                self.pclose()
-            }
-        }
-        self.ann.post(self, AnnNode::Expr(expr));
-        self.end();
-    }
-
     fn print_inline_asm(&mut self, asm: &ast::InlineAsm) {
         enum AsmArg<'a> {
             Template(String),
@@ -2496,48 +1483,6 @@ impl<'a> State<'a> {
         self.ann.post(self, AnnNode::Pat(pat))
     }
 
-    fn print_arm(&mut self, arm: &ast::Arm) {
-        // Note, I have no idea why this check is necessary, but here it is.
-        if arm.attrs.is_empty() {
-            self.space();
-        }
-        self.cbox(INDENT_UNIT);
-        self.ibox(0);
-        self.maybe_print_comment(arm.pat.span.lo());
-        self.print_outer_attributes(&arm.attrs);
-        self.print_pat(&arm.pat);
-        self.space();
-        if let Some(ref e) = arm.guard {
-            self.word_space("if");
-            self.print_expr(e);
-            self.space();
-        }
-        self.word_space("=>");
-
-        match arm.body.kind {
-            ast::ExprKind::Block(ref blk, opt_label) => {
-                if let Some(label) = opt_label {
-                    self.print_ident(label.ident);
-                    self.word_space(":");
-                }
-
-                // The block will close the pattern's ibox.
-                self.print_block_unclosed_indent(blk);
-
-                // If it is a user-provided unsafe block, print a comma after it.
-                if let BlockCheckMode::Unsafe(ast::UserProvided) = blk.rules {
-                    self.word(",");
-                }
-            }
-            _ => {
-                self.end(); // Close the ibox for the pattern.
-                self.print_expr(&arm.body);
-                self.word(",");
-            }
-        }
-        self.end(); // Close enclosing cbox.
-    }
-
     fn print_explicit_self(&mut self, explicit_self: &ast::ExplicitSelf) {
         match explicit_self.node {
             SelfKind::Value(m) => {
@@ -2559,75 +1504,12 @@ impl<'a> State<'a> {
         }
     }
 
-    fn print_fn_full(
-        &mut self,
-        sig: &ast::FnSig,
-        name: Ident,
-        generics: &ast::Generics,
-        vis: &ast::Visibility,
-        defaultness: ast::Defaultness,
-        body: Option<&ast::Block>,
-        attrs: &[ast::Attribute],
-    ) {
-        if body.is_some() {
-            self.head("");
-        }
-        self.print_visibility(vis);
-        self.print_defaultness(defaultness);
-        self.print_fn(&sig.decl, sig.header, Some(name), generics);
-        if let Some(body) = body {
-            self.nbsp();
-            self.print_block_with_attrs(body, attrs);
-        } else {
-            self.word(";");
-        }
-    }
-
-    crate fn print_fn(
-        &mut self,
-        decl: &ast::FnDecl,
-        header: ast::FnHeader,
-        name: Option<Ident>,
-        generics: &ast::Generics,
-    ) {
-        self.print_fn_header_info(header);
-        if let Some(name) = name {
-            self.nbsp();
-            self.print_ident(name);
-        }
-        self.print_generic_params(&generics.params);
-        self.print_fn_params_and_ret(decl, false);
-        self.print_where_clause(&generics.where_clause)
-    }
-
-    crate fn print_fn_params_and_ret(&mut self, decl: &ast::FnDecl, is_closure: bool) {
-        let (open, close) = if is_closure { ("|", "|") } else { ("(", ")") };
-        self.word(open);
-        self.commasep(Inconsistent, &decl.inputs, |s, param| s.print_param(param, is_closure));
-        self.word(close);
-        self.print_fn_ret_ty(&decl.output)
-    }
-
-    crate fn print_movability(&mut self, movability: ast::Movability) {
-        match movability {
-            ast::Movability::Static => self.word_space("static"),
-            ast::Movability::Movable => {}
-        }
-    }
-
     crate fn print_asyncness(&mut self, asyncness: ast::Async) {
         if asyncness.is_async() {
             self.word_nbsp("async");
         }
     }
 
-    crate fn print_capture_clause(&mut self, capture_clause: ast::CaptureBy) {
-        match capture_clause {
-            ast::CaptureBy::Value => self.word_space("move"),
-            ast::CaptureBy::Ref => {}
-        }
-    }
-
     pub fn print_type_bounds(&mut self, prefix: &'static str, bounds: &[ast::GenericBound]) {
         if !bounds.is_empty() {
             self.word(prefix);
@@ -2722,83 +1604,6 @@ impl<'a> State<'a> {
         self.word(">");
     }
 
-    crate fn print_where_clause(&mut self, where_clause: &ast::WhereClause) {
-        if where_clause.predicates.is_empty() && !where_clause.has_where_token {
-            return;
-        }
-
-        self.space();
-        self.word_space("where");
-
-        for (i, predicate) in where_clause.predicates.iter().enumerate() {
-            if i != 0 {
-                self.word_space(",");
-            }
-
-            self.print_where_predicate(predicate);
-        }
-    }
-
-    pub fn print_where_predicate(&mut self, predicate: &ast::WherePredicate) {
-        match predicate {
-            ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate {
-                bound_generic_params,
-                bounded_ty,
-                bounds,
-                ..
-            }) => {
-                self.print_formal_generic_params(bound_generic_params);
-                self.print_type(bounded_ty);
-                self.print_type_bounds(":", bounds);
-            }
-            ast::WherePredicate::RegionPredicate(ast::WhereRegionPredicate {
-                lifetime,
-                bounds,
-                ..
-            }) => {
-                self.print_lifetime_bounds(*lifetime, bounds);
-            }
-            ast::WherePredicate::EqPredicate(ast::WhereEqPredicate { lhs_ty, rhs_ty, .. }) => {
-                self.print_type(lhs_ty);
-                self.space();
-                self.word_space("=");
-                self.print_type(rhs_ty);
-            }
-        }
-    }
-
-    crate fn print_use_tree(&mut self, tree: &ast::UseTree) {
-        match tree.kind {
-            ast::UseTreeKind::Simple(rename, ..) => {
-                self.print_path(&tree.prefix, false, 0);
-                if let Some(rename) = rename {
-                    self.space();
-                    self.word_space("as");
-                    self.print_ident(rename);
-                }
-            }
-            ast::UseTreeKind::Glob => {
-                if !tree.prefix.segments.is_empty() {
-                    self.print_path(&tree.prefix, false, 0);
-                    self.word("::");
-                }
-                self.word("*");
-            }
-            ast::UseTreeKind::Nested(ref items) => {
-                if tree.prefix.segments.is_empty() {
-                    self.word("{");
-                } else {
-                    self.print_path(&tree.prefix, false, 0);
-                    self.word("::{");
-                }
-                self.commasep(Inconsistent, &items, |this, &(ref tree, _)| {
-                    this.print_use_tree(tree)
-                });
-                self.word("}");
-            }
-        }
-    }
-
     pub fn print_mutability(&mut self, mutbl: ast::Mutability, print_const: bool) {
         match mutbl {
             ast::Mutability::Mut => self.word_nbsp("mut"),
diff --git a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
new file mode 100644
index 00000000000..956200d60f5
--- /dev/null
+++ b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
@@ -0,0 +1,571 @@
+use crate::pp::Breaks::{Consistent, Inconsistent};
+use crate::pprust::state::{AnnNode, PrintState, State, INDENT_UNIT};
+
+use rustc_ast::ptr::P;
+use rustc_ast::util::parser::{self, AssocOp, Fixity};
+use rustc_ast::{self as ast, BlockCheckMode};
+
+impl<'a> State<'a> {
+    fn print_else(&mut self, els: Option<&ast::Expr>) {
+        if let Some(_else) = els {
+            match _else.kind {
+                // Another `else if` block.
+                ast::ExprKind::If(ref i, ref then, ref e) => {
+                    self.cbox(INDENT_UNIT - 1);
+                    self.ibox(0);
+                    self.word(" else if ");
+                    self.print_expr_as_cond(i);
+                    self.space();
+                    self.print_block(then);
+                    self.print_else(e.as_deref())
+                }
+                // Final `else` block.
+                ast::ExprKind::Block(ref b, _) => {
+                    self.cbox(INDENT_UNIT - 1);
+                    self.ibox(0);
+                    self.word(" else ");
+                    self.print_block(b)
+                }
+                // Constraints would be great here!
+                _ => {
+                    panic!("print_if saw if with weird alternative");
+                }
+            }
+        }
+    }
+
+    fn print_if(&mut self, test: &ast::Expr, blk: &ast::Block, elseopt: Option<&ast::Expr>) {
+        self.head("if");
+        self.print_expr_as_cond(test);
+        self.space();
+        self.print_block(blk);
+        self.print_else(elseopt)
+    }
+
+    fn print_call_post(&mut self, args: &[P<ast::Expr>]) {
+        self.popen();
+        self.commasep_exprs(Inconsistent, args);
+        self.pclose()
+    }
+
+    fn print_expr_maybe_paren(&mut self, expr: &ast::Expr, prec: i8) {
+        self.print_expr_cond_paren(expr, expr.precedence().order() < prec)
+    }
+
+    /// Prints an expr using syntax that's acceptable in a condition position, such as the `cond` in
+    /// `if cond { ... }`.
+    fn print_expr_as_cond(&mut self, expr: &ast::Expr) {
+        self.print_expr_cond_paren(expr, Self::cond_needs_par(expr))
+    }
+
+    // Does `expr` need parentheses when printed in a condition position?
+    //
+    // These cases need parens due to the parse error observed in #26461: `if return {}`
+    // parses as the erroneous construct `if (return {})`, not `if (return) {}`.
+    pub(super) fn cond_needs_par(expr: &ast::Expr) -> bool {
+        match expr.kind {
+            ast::ExprKind::Break(..) | ast::ExprKind::Closure(..) | ast::ExprKind::Ret(..) => true,
+            _ => parser::contains_exterior_struct_lit(expr),
+        }
+    }
+
+    /// Prints `expr` or `(expr)` when `needs_par` holds.
+    pub(super) fn print_expr_cond_paren(&mut self, expr: &ast::Expr, needs_par: bool) {
+        if needs_par {
+            self.popen();
+        }
+        self.print_expr(expr);
+        if needs_par {
+            self.pclose();
+        }
+    }
+
+    fn print_expr_vec(&mut self, exprs: &[P<ast::Expr>]) {
+        self.ibox(INDENT_UNIT);
+        self.word("[");
+        self.commasep_exprs(Inconsistent, exprs);
+        self.word("]");
+        self.end();
+    }
+
+    pub(super) fn print_expr_anon_const(&mut self, expr: &ast::AnonConst) {
+        self.ibox(INDENT_UNIT);
+        self.word("const");
+        self.print_expr(&expr.value);
+        self.end();
+    }
+
+    fn print_expr_repeat(&mut self, element: &ast::Expr, count: &ast::AnonConst) {
+        self.ibox(INDENT_UNIT);
+        self.word("[");
+        self.print_expr(element);
+        self.word_space(";");
+        self.print_expr(&count.value);
+        self.word("]");
+        self.end();
+    }
+
+    fn print_expr_struct(
+        &mut self,
+        qself: &Option<ast::QSelf>,
+        path: &ast::Path,
+        fields: &[ast::ExprField],
+        rest: &ast::StructRest,
+    ) {
+        if let Some(qself) = qself {
+            self.print_qpath(path, qself, true);
+        } else {
+            self.print_path(path, true, 0);
+        }
+        self.word("{");
+        self.commasep_cmnt(
+            Consistent,
+            fields,
+            |s, field| {
+                s.print_outer_attributes(&field.attrs);
+                s.ibox(INDENT_UNIT);
+                if !field.is_shorthand {
+                    s.print_ident(field.ident);
+                    s.word_space(":");
+                }
+                s.print_expr(&field.expr);
+                s.end();
+            },
+            |f| f.span,
+        );
+        match rest {
+            ast::StructRest::Base(_) | ast::StructRest::Rest(_) => {
+                self.ibox(INDENT_UNIT);
+                if !fields.is_empty() {
+                    self.word(",");
+                    self.space();
+                }
+                self.word("..");
+                if let ast::StructRest::Base(ref expr) = *rest {
+                    self.print_expr(expr);
+                }
+                self.end();
+            }
+            ast::StructRest::None if !fields.is_empty() => self.word(","),
+            _ => {}
+        }
+        self.word("}");
+    }
+
+    fn print_expr_tup(&mut self, exprs: &[P<ast::Expr>]) {
+        self.popen();
+        self.commasep_exprs(Inconsistent, exprs);
+        if exprs.len() == 1 {
+            self.word(",");
+        }
+        self.pclose()
+    }
+
+    fn print_expr_call(&mut self, func: &ast::Expr, args: &[P<ast::Expr>]) {
+        let prec = match func.kind {
+            ast::ExprKind::Field(..) => parser::PREC_FORCE_PAREN,
+            _ => parser::PREC_POSTFIX,
+        };
+
+        self.print_expr_maybe_paren(func, prec);
+        self.print_call_post(args)
+    }
+
+    fn print_expr_method_call(&mut self, segment: &ast::PathSegment, args: &[P<ast::Expr>]) {
+        let base_args = &args[1..];
+        self.print_expr_maybe_paren(&args[0], parser::PREC_POSTFIX);
+        self.word(".");
+        self.print_ident(segment.ident);
+        if let Some(ref args) = segment.args {
+            self.print_generic_args(args, true);
+        }
+        self.print_call_post(base_args)
+    }
+
+    fn print_expr_binary(&mut self, op: ast::BinOp, lhs: &ast::Expr, rhs: &ast::Expr) {
+        let assoc_op = AssocOp::from_ast_binop(op.node);
+        let prec = assoc_op.precedence() as i8;
+        let fixity = assoc_op.fixity();
+
+        let (left_prec, right_prec) = match fixity {
+            Fixity::Left => (prec, prec + 1),
+            Fixity::Right => (prec + 1, prec),
+            Fixity::None => (prec + 1, prec + 1),
+        };
+
+        let left_prec = match (&lhs.kind, op.node) {
+            // These cases need parens: `x as i32 < y` has the parser thinking that `i32 < y` is
+            // the beginning of a path type. It starts trying to parse `x as (i32 < y ...` instead
+            // of `(x as i32) < ...`. We need to convince it _not_ to do that.
+            (&ast::ExprKind::Cast { .. }, ast::BinOpKind::Lt | ast::BinOpKind::Shl) => {
+                parser::PREC_FORCE_PAREN
+            }
+            // We are given `(let _ = a) OP b`.
+            //
+            // - When `OP <= LAnd` we should print `let _ = a OP b` to avoid redundant parens
+            //   as the parser will interpret this as `(let _ = a) OP b`.
+            //
+            // - Otherwise, e.g. when we have `(let a = b) < c` in AST,
+            //   parens are required since the parser would interpret `let a = b < c` as
+            //   `let a = (b < c)`. To achieve this, we force parens.
+            (&ast::ExprKind::Let { .. }, _) if !parser::needs_par_as_let_scrutinee(prec) => {
+                parser::PREC_FORCE_PAREN
+            }
+            _ => left_prec,
+        };
+
+        self.print_expr_maybe_paren(lhs, left_prec);
+        self.space();
+        self.word_space(op.node.to_string());
+        self.print_expr_maybe_paren(rhs, right_prec)
+    }
+
+    fn print_expr_unary(&mut self, op: ast::UnOp, expr: &ast::Expr) {
+        self.word(ast::UnOp::to_string(op));
+        self.print_expr_maybe_paren(expr, parser::PREC_PREFIX)
+    }
+
+    fn print_expr_addr_of(
+        &mut self,
+        kind: ast::BorrowKind,
+        mutability: ast::Mutability,
+        expr: &ast::Expr,
+    ) {
+        self.word("&");
+        match kind {
+            ast::BorrowKind::Ref => self.print_mutability(mutability, false),
+            ast::BorrowKind::Raw => {
+                self.word_nbsp("raw");
+                self.print_mutability(mutability, true);
+            }
+        }
+        self.print_expr_maybe_paren(expr, parser::PREC_PREFIX)
+    }
+
+    pub fn print_expr(&mut self, expr: &ast::Expr) {
+        self.print_expr_outer_attr_style(expr, true)
+    }
+
+    pub(super) fn print_expr_outer_attr_style(&mut self, expr: &ast::Expr, is_inline: bool) {
+        self.maybe_print_comment(expr.span.lo());
+
+        let attrs = &expr.attrs;
+        if is_inline {
+            self.print_outer_attributes_inline(attrs);
+        } else {
+            self.print_outer_attributes(attrs);
+        }
+
+        self.ibox(INDENT_UNIT);
+        self.ann.pre(self, AnnNode::Expr(expr));
+        match expr.kind {
+            ast::ExprKind::Box(ref expr) => {
+                self.word_space("box");
+                self.print_expr_maybe_paren(expr, parser::PREC_PREFIX);
+            }
+            ast::ExprKind::Array(ref exprs) => {
+                self.print_expr_vec(exprs);
+            }
+            ast::ExprKind::ConstBlock(ref anon_const) => {
+                self.print_expr_anon_const(anon_const);
+            }
+            ast::ExprKind::Repeat(ref element, ref count) => {
+                self.print_expr_repeat(element, count);
+            }
+            ast::ExprKind::Struct(ref se) => {
+                self.print_expr_struct(&se.qself, &se.path, &se.fields, &se.rest);
+            }
+            ast::ExprKind::Tup(ref exprs) => {
+                self.print_expr_tup(exprs);
+            }
+            ast::ExprKind::Call(ref func, ref args) => {
+                self.print_expr_call(func, &args);
+            }
+            ast::ExprKind::MethodCall(ref segment, ref args, _) => {
+                self.print_expr_method_call(segment, &args);
+            }
+            ast::ExprKind::Binary(op, ref lhs, ref rhs) => {
+                self.print_expr_binary(op, lhs, rhs);
+            }
+            ast::ExprKind::Unary(op, ref expr) => {
+                self.print_expr_unary(op, expr);
+            }
+            ast::ExprKind::AddrOf(k, m, ref expr) => {
+                self.print_expr_addr_of(k, m, expr);
+            }
+            ast::ExprKind::Lit(ref lit) => {
+                self.print_literal(lit);
+            }
+            ast::ExprKind::Cast(ref expr, ref ty) => {
+                let prec = AssocOp::As.precedence() as i8;
+                self.print_expr_maybe_paren(expr, prec);
+                self.space();
+                self.word_space("as");
+                self.print_type(ty);
+            }
+            ast::ExprKind::Type(ref expr, ref ty) => {
+                let prec = AssocOp::Colon.precedence() as i8;
+                self.print_expr_maybe_paren(expr, prec);
+                self.word_space(":");
+                self.print_type(ty);
+            }
+            ast::ExprKind::Let(ref pat, ref scrutinee, _) => {
+                self.print_let(pat, scrutinee);
+            }
+            ast::ExprKind::If(ref test, ref blk, ref elseopt) => {
+                self.print_if(test, blk, elseopt.as_deref())
+            }
+            ast::ExprKind::While(ref test, ref blk, opt_label) => {
+                if let Some(label) = opt_label {
+                    self.print_ident(label.ident);
+                    self.word_space(":");
+                }
+                self.head("while");
+                self.print_expr_as_cond(test);
+                self.space();
+                self.print_block_with_attrs(blk, attrs);
+            }
+            ast::ExprKind::ForLoop(ref pat, ref iter, ref blk, opt_label) => {
+                if let Some(label) = opt_label {
+                    self.print_ident(label.ident);
+                    self.word_space(":");
+                }
+                self.head("for");
+                self.print_pat(pat);
+                self.space();
+                self.word_space("in");
+                self.print_expr_as_cond(iter);
+                self.space();
+                self.print_block_with_attrs(blk, attrs);
+            }
+            ast::ExprKind::Loop(ref blk, opt_label) => {
+                if let Some(label) = opt_label {
+                    self.print_ident(label.ident);
+                    self.word_space(":");
+                }
+                self.head("loop");
+                self.print_block_with_attrs(blk, attrs);
+            }
+            ast::ExprKind::Match(ref expr, ref arms) => {
+                self.cbox(INDENT_UNIT);
+                self.ibox(INDENT_UNIT);
+                self.word_nbsp("match");
+                self.print_expr_as_cond(expr);
+                self.space();
+                self.bopen();
+                self.print_inner_attributes_no_trailing_hardbreak(attrs);
+                for arm in arms {
+                    self.print_arm(arm);
+                }
+                let empty = attrs.is_empty() && arms.is_empty();
+                self.bclose(expr.span, empty);
+            }
+            ast::ExprKind::Closure(
+                capture_clause,
+                asyncness,
+                movability,
+                ref decl,
+                ref body,
+                _,
+            ) => {
+                self.print_movability(movability);
+                self.print_asyncness(asyncness);
+                self.print_capture_clause(capture_clause);
+
+                self.print_fn_params_and_ret(decl, true);
+                self.space();
+                self.print_expr(body);
+                self.end(); // need to close a box
+
+                // a box will be closed by print_expr, but we didn't want an overall
+                // wrapper so we closed the corresponding opening. so create an
+                // empty box to satisfy the close.
+                self.ibox(0);
+            }
+            ast::ExprKind::Block(ref blk, opt_label) => {
+                if let Some(label) = opt_label {
+                    self.print_ident(label.ident);
+                    self.word_space(":");
+                }
+                // containing cbox, will be closed by print-block at }
+                self.cbox(INDENT_UNIT);
+                // head-box, will be closed by print-block after {
+                self.ibox(0);
+                self.print_block_with_attrs(blk, attrs);
+            }
+            ast::ExprKind::Async(capture_clause, _, ref blk) => {
+                self.word_nbsp("async");
+                self.print_capture_clause(capture_clause);
+                // cbox/ibox in analogy to the `ExprKind::Block` arm above
+                self.cbox(INDENT_UNIT);
+                self.ibox(0);
+                self.print_block_with_attrs(blk, attrs);
+            }
+            ast::ExprKind::Await(ref expr) => {
+                self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
+                self.word(".await");
+            }
+            ast::ExprKind::Assign(ref lhs, ref rhs, _) => {
+                let prec = AssocOp::Assign.precedence() as i8;
+                self.print_expr_maybe_paren(lhs, prec + 1);
+                self.space();
+                self.word_space("=");
+                self.print_expr_maybe_paren(rhs, prec);
+            }
+            ast::ExprKind::AssignOp(op, ref lhs, ref rhs) => {
+                let prec = AssocOp::Assign.precedence() as i8;
+                self.print_expr_maybe_paren(lhs, prec + 1);
+                self.space();
+                self.word(op.node.to_string());
+                self.word_space("=");
+                self.print_expr_maybe_paren(rhs, prec);
+            }
+            ast::ExprKind::Field(ref expr, ident) => {
+                self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
+                self.word(".");
+                self.print_ident(ident);
+            }
+            ast::ExprKind::Index(ref expr, ref index) => {
+                self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
+                self.word("[");
+                self.print_expr(index);
+                self.word("]");
+            }
+            ast::ExprKind::Range(ref start, ref end, limits) => {
+                // Special case for `Range`.  `AssocOp` claims that `Range` has higher precedence
+                // than `Assign`, but `x .. x = x` gives a parse error instead of `x .. (x = x)`.
+                // Here we use a fake precedence value so that any child with lower precedence than
+                // a "normal" binop gets parenthesized.  (`LOr` is the lowest-precedence binop.)
+                let fake_prec = AssocOp::LOr.precedence() as i8;
+                if let Some(ref e) = *start {
+                    self.print_expr_maybe_paren(e, fake_prec);
+                }
+                if limits == ast::RangeLimits::HalfOpen {
+                    self.word("..");
+                } else {
+                    self.word("..=");
+                }
+                if let Some(ref e) = *end {
+                    self.print_expr_maybe_paren(e, fake_prec);
+                }
+            }
+            ast::ExprKind::Underscore => self.word("_"),
+            ast::ExprKind::Path(None, ref path) => self.print_path(path, true, 0),
+            ast::ExprKind::Path(Some(ref qself), ref path) => self.print_qpath(path, qself, true),
+            ast::ExprKind::Break(opt_label, ref opt_expr) => {
+                self.word("break");
+                if let Some(label) = opt_label {
+                    self.space();
+                    self.print_ident(label.ident);
+                }
+                if let Some(ref expr) = *opt_expr {
+                    self.space();
+                    self.print_expr_maybe_paren(expr, parser::PREC_JUMP);
+                }
+            }
+            ast::ExprKind::Continue(opt_label) => {
+                self.word("continue");
+                if let Some(label) = opt_label {
+                    self.space();
+                    self.print_ident(label.ident);
+                }
+            }
+            ast::ExprKind::Ret(ref result) => {
+                self.word("return");
+                if let Some(ref expr) = *result {
+                    self.word(" ");
+                    self.print_expr_maybe_paren(expr, parser::PREC_JUMP);
+                }
+            }
+            ast::ExprKind::InlineAsm(ref a) => {
+                self.word("asm!");
+                self.print_inline_asm(a);
+            }
+            ast::ExprKind::MacCall(ref m) => self.print_mac(m),
+            ast::ExprKind::Paren(ref e) => {
+                self.popen();
+                self.print_expr(e);
+                self.pclose();
+            }
+            ast::ExprKind::Yield(ref e) => {
+                self.word("yield");
+
+                if let Some(ref expr) = *e {
+                    self.space();
+                    self.print_expr_maybe_paren(expr, parser::PREC_JUMP);
+                }
+            }
+            ast::ExprKind::Try(ref e) => {
+                self.print_expr_maybe_paren(e, parser::PREC_POSTFIX);
+                self.word("?")
+            }
+            ast::ExprKind::TryBlock(ref blk) => {
+                self.head("try");
+                self.print_block_with_attrs(blk, attrs)
+            }
+            ast::ExprKind::Err => {
+                self.popen();
+                self.word("/*ERROR*/");
+                self.pclose()
+            }
+        }
+        self.ann.post(self, AnnNode::Expr(expr));
+        self.end();
+    }
+
+    fn print_arm(&mut self, arm: &ast::Arm) {
+        // Note, I have no idea why this check is necessary, but here it is.
+        if arm.attrs.is_empty() {
+            self.space();
+        }
+        self.cbox(INDENT_UNIT);
+        self.ibox(0);
+        self.maybe_print_comment(arm.pat.span.lo());
+        self.print_outer_attributes(&arm.attrs);
+        self.print_pat(&arm.pat);
+        self.space();
+        if let Some(ref e) = arm.guard {
+            self.word_space("if");
+            self.print_expr(e);
+            self.space();
+        }
+        self.word_space("=>");
+
+        match arm.body.kind {
+            ast::ExprKind::Block(ref blk, opt_label) => {
+                if let Some(label) = opt_label {
+                    self.print_ident(label.ident);
+                    self.word_space(":");
+                }
+
+                // The block will close the pattern's ibox.
+                self.print_block_unclosed_indent(blk);
+
+                // If it is a user-provided unsafe block, print a comma after it.
+                if let BlockCheckMode::Unsafe(ast::UserProvided) = blk.rules {
+                    self.word(",");
+                }
+            }
+            _ => {
+                self.end(); // Close the ibox for the pattern.
+                self.print_expr(&arm.body);
+                self.word(",");
+            }
+        }
+        self.end(); // Close enclosing cbox.
+    }
+
+    fn print_movability(&mut self, movability: ast::Movability) {
+        match movability {
+            ast::Movability::Static => self.word_space("static"),
+            ast::Movability::Movable => {}
+        }
+    }
+
+    fn print_capture_clause(&mut self, capture_clause: ast::CaptureBy) {
+        match capture_clause {
+            ast::CaptureBy::Value => self.word_space("move"),
+            ast::CaptureBy::Ref => {}
+        }
+    }
+}
diff --git a/compiler/rustc_ast_pretty/src/pprust/state/item.rs b/compiler/rustc_ast_pretty/src/pprust/state/item.rs
new file mode 100644
index 00000000000..c756b946b1e
--- /dev/null
+++ b/compiler/rustc_ast_pretty/src/pprust/state/item.rs
@@ -0,0 +1,644 @@
+use crate::pp::Breaks::Inconsistent;
+use crate::pprust::state::{AnnNode, PrintState, State, INDENT_UNIT};
+
+use rustc_ast as ast;
+use rustc_ast::GenericBound;
+use rustc_ast::ModKind;
+use rustc_span::symbol::Ident;
+
+fn visibility_qualified(vis: &ast::Visibility, s: &str) -> String {
+    format!("{}{}", State::to_string(|s| s.print_visibility(vis)), s)
+}
+
+impl<'a> State<'a> {
+    fn print_foreign_mod(&mut self, nmod: &ast::ForeignMod, attrs: &[ast::Attribute]) {
+        self.print_inner_attributes(attrs);
+        for item in &nmod.items {
+            self.print_foreign_item(item);
+        }
+    }
+
+    fn print_foreign_item(&mut self, item: &ast::ForeignItem) {
+        let ast::Item { id, span, ident, ref attrs, ref kind, ref vis, tokens: _ } = *item;
+        self.ann.pre(self, AnnNode::SubItem(id));
+        self.hardbreak_if_not_bol();
+        self.maybe_print_comment(span.lo());
+        self.print_outer_attributes(attrs);
+        match kind {
+            ast::ForeignItemKind::Fn(box ast::Fn { defaultness, sig, generics, body }) => {
+                self.print_fn_full(sig, ident, generics, vis, *defaultness, body.as_deref(), attrs);
+            }
+            ast::ForeignItemKind::Static(ty, mutbl, body) => {
+                let def = ast::Defaultness::Final;
+                self.print_item_const(ident, Some(*mutbl), ty, body.as_deref(), vis, def);
+            }
+            ast::ForeignItemKind::TyAlias(box ast::TyAlias {
+                defaultness,
+                generics,
+                bounds,
+                ty,
+            }) => {
+                self.print_associated_type(
+                    ident,
+                    generics,
+                    bounds,
+                    ty.as_deref(),
+                    vis,
+                    *defaultness,
+                );
+            }
+            ast::ForeignItemKind::MacCall(m) => {
+                self.print_mac(m);
+                if m.args.need_semicolon() {
+                    self.word(";");
+                }
+            }
+        }
+        self.ann.post(self, AnnNode::SubItem(id))
+    }
+
+    fn print_item_const(
+        &mut self,
+        ident: Ident,
+        mutbl: Option<ast::Mutability>,
+        ty: &ast::Ty,
+        body: Option<&ast::Expr>,
+        vis: &ast::Visibility,
+        defaultness: ast::Defaultness,
+    ) {
+        self.head("");
+        self.print_visibility(vis);
+        self.print_defaultness(defaultness);
+        let leading = match mutbl {
+            None => "const",
+            Some(ast::Mutability::Not) => "static",
+            Some(ast::Mutability::Mut) => "static mut",
+        };
+        self.word_space(leading);
+        self.print_ident(ident);
+        self.word_space(":");
+        self.print_type(ty);
+        if body.is_some() {
+            self.space();
+        }
+        self.end(); // end the head-ibox
+        if let Some(body) = body {
+            self.word_space("=");
+            self.print_expr(body);
+        }
+        self.word(";");
+        self.end(); // end the outer cbox
+    }
+
+    fn print_associated_type(
+        &mut self,
+        ident: Ident,
+        generics: &ast::Generics,
+        bounds: &ast::GenericBounds,
+        ty: Option<&ast::Ty>,
+        vis: &ast::Visibility,
+        defaultness: ast::Defaultness,
+    ) {
+        self.head("");
+        self.print_visibility(vis);
+        self.print_defaultness(defaultness);
+        self.word_space("type");
+        self.print_ident(ident);
+        self.print_generic_params(&generics.params);
+        self.print_type_bounds(":", bounds);
+        self.print_where_clause(&generics.where_clause);
+        if let Some(ty) = ty {
+            self.space();
+            self.word_space("=");
+            self.print_type(ty);
+        }
+        self.word(";");
+        self.end(); // end inner head-block
+        self.end(); // end outer head-block
+    }
+
+    /// Pretty-prints an item.
+    crate fn print_item(&mut self, item: &ast::Item) {
+        self.hardbreak_if_not_bol();
+        self.maybe_print_comment(item.span.lo());
+        self.print_outer_attributes(&item.attrs);
+        self.ann.pre(self, AnnNode::Item(item));
+        match item.kind {
+            ast::ItemKind::ExternCrate(orig_name) => {
+                self.head(visibility_qualified(&item.vis, "extern crate"));
+                if let Some(orig_name) = orig_name {
+                    self.print_name(orig_name);
+                    self.space();
+                    self.word("as");
+                    self.space();
+                }
+                self.print_ident(item.ident);
+                self.word(";");
+                self.end(); // end inner head-block
+                self.end(); // end outer head-block
+            }
+            ast::ItemKind::Use(ref tree) => {
+                self.head(visibility_qualified(&item.vis, "use"));
+                self.print_use_tree(tree);
+                self.word(";");
+                self.end(); // end inner head-block
+                self.end(); // end outer head-block
+            }
+            ast::ItemKind::Static(ref ty, mutbl, ref body) => {
+                let def = ast::Defaultness::Final;
+                self.print_item_const(item.ident, Some(mutbl), ty, body.as_deref(), &item.vis, def);
+            }
+            ast::ItemKind::Const(def, ref ty, ref body) => {
+                self.print_item_const(item.ident, None, ty, body.as_deref(), &item.vis, def);
+            }
+            ast::ItemKind::Fn(box ast::Fn { defaultness, ref sig, ref generics, ref body }) => {
+                let body = body.as_deref();
+                self.print_fn_full(
+                    sig,
+                    item.ident,
+                    generics,
+                    &item.vis,
+                    defaultness,
+                    body,
+                    &item.attrs,
+                );
+            }
+            ast::ItemKind::Mod(unsafety, ref mod_kind) => {
+                self.head(Self::to_string(|s| {
+                    s.print_visibility(&item.vis);
+                    s.print_unsafety(unsafety);
+                    s.word("mod");
+                }));
+                self.print_ident(item.ident);
+
+                match mod_kind {
+                    ModKind::Loaded(items, ..) => {
+                        self.nbsp();
+                        self.bopen();
+                        self.print_inner_attributes(&item.attrs);
+                        for item in items {
+                            self.print_item(item);
+                        }
+                        let empty = item.attrs.is_empty() && items.is_empty();
+                        self.bclose(item.span, empty);
+                    }
+                    ModKind::Unloaded => {
+                        self.word(";");
+                        self.end(); // end inner head-block
+                        self.end(); // end outer head-block
+                    }
+                }
+            }
+            ast::ItemKind::ForeignMod(ref nmod) => {
+                self.head(Self::to_string(|s| {
+                    s.print_unsafety(nmod.unsafety);
+                    s.word("extern");
+                }));
+                if let Some(abi) = nmod.abi {
+                    self.print_literal(&abi.as_lit());
+                    self.nbsp();
+                }
+                self.bopen();
+                self.print_foreign_mod(nmod, &item.attrs);
+                let empty = item.attrs.is_empty() && nmod.items.is_empty();
+                self.bclose(item.span, empty);
+            }
+            ast::ItemKind::GlobalAsm(ref asm) => {
+                self.head(visibility_qualified(&item.vis, "global_asm!"));
+                self.print_inline_asm(asm);
+                self.end();
+            }
+            ast::ItemKind::TyAlias(box ast::TyAlias {
+                defaultness,
+                ref generics,
+                ref bounds,
+                ref ty,
+            }) => {
+                let ty = ty.as_deref();
+                self.print_associated_type(
+                    item.ident,
+                    generics,
+                    bounds,
+                    ty,
+                    &item.vis,
+                    defaultness,
+                );
+            }
+            ast::ItemKind::Enum(ref enum_definition, ref params) => {
+                self.print_enum_def(enum_definition, params, item.ident, item.span, &item.vis);
+            }
+            ast::ItemKind::Struct(ref struct_def, ref generics) => {
+                self.head(visibility_qualified(&item.vis, "struct"));
+                self.print_struct(struct_def, generics, item.ident, item.span, true);
+            }
+            ast::ItemKind::Union(ref struct_def, ref generics) => {
+                self.head(visibility_qualified(&item.vis, "union"));
+                self.print_struct(struct_def, generics, item.ident, item.span, true);
+            }
+            ast::ItemKind::Impl(box ast::Impl {
+                unsafety,
+                polarity,
+                defaultness,
+                constness,
+                ref generics,
+                ref of_trait,
+                ref self_ty,
+                ref items,
+            }) => {
+                self.head("");
+                self.print_visibility(&item.vis);
+                self.print_defaultness(defaultness);
+                self.print_unsafety(unsafety);
+                self.word("impl");
+
+                if generics.params.is_empty() {
+                    self.nbsp();
+                } else {
+                    self.print_generic_params(&generics.params);
+                    self.space();
+                }
+
+                self.print_constness(constness);
+
+                if let ast::ImplPolarity::Negative(_) = polarity {
+                    self.word("!");
+                }
+
+                if let Some(ref t) = *of_trait {
+                    self.print_trait_ref(t);
+                    self.space();
+                    self.word_space("for");
+                }
+
+                self.print_type(self_ty);
+                self.print_where_clause(&generics.where_clause);
+
+                self.space();
+                self.bopen();
+                self.print_inner_attributes(&item.attrs);
+                for impl_item in items {
+                    self.print_assoc_item(impl_item);
+                }
+                let empty = item.attrs.is_empty() && items.is_empty();
+                self.bclose(item.span, empty);
+            }
+            ast::ItemKind::Trait(box ast::Trait {
+                is_auto,
+                unsafety,
+                ref generics,
+                ref bounds,
+                ref items,
+                ..
+            }) => {
+                self.head("");
+                self.print_visibility(&item.vis);
+                self.print_unsafety(unsafety);
+                self.print_is_auto(is_auto);
+                self.word_nbsp("trait");
+                self.print_ident(item.ident);
+                self.print_generic_params(&generics.params);
+                let mut real_bounds = Vec::with_capacity(bounds.len());
+                for b in bounds.iter() {
+                    if let GenericBound::Trait(ref ptr, ast::TraitBoundModifier::Maybe) = *b {
+                        self.space();
+                        self.word_space("for ?");
+                        self.print_trait_ref(&ptr.trait_ref);
+                    } else {
+                        real_bounds.push(b.clone());
+                    }
+                }
+                self.print_type_bounds(":", &real_bounds);
+                self.print_where_clause(&generics.where_clause);
+                self.word(" ");
+                self.bopen();
+                self.print_inner_attributes(&item.attrs);
+                for trait_item in items {
+                    self.print_assoc_item(trait_item);
+                }
+                let empty = item.attrs.is_empty() && items.is_empty();
+                self.bclose(item.span, empty);
+            }
+            ast::ItemKind::TraitAlias(ref generics, ref bounds) => {
+                self.head(visibility_qualified(&item.vis, "trait"));
+                self.print_ident(item.ident);
+                self.print_generic_params(&generics.params);
+                let mut real_bounds = Vec::with_capacity(bounds.len());
+                // FIXME(durka) this seems to be some quite outdated syntax
+                for b in bounds.iter() {
+                    if let GenericBound::Trait(ref ptr, ast::TraitBoundModifier::Maybe) = *b {
+                        self.space();
+                        self.word_space("for ?");
+                        self.print_trait_ref(&ptr.trait_ref);
+                    } else {
+                        real_bounds.push(b.clone());
+                    }
+                }
+                self.nbsp();
+                self.print_type_bounds("=", &real_bounds);
+                self.print_where_clause(&generics.where_clause);
+                self.word(";");
+                self.end(); // end inner head-block
+                self.end(); // end outer head-block
+            }
+            ast::ItemKind::MacCall(ref mac) => {
+                self.print_mac(mac);
+                if mac.args.need_semicolon() {
+                    self.word(";");
+                }
+            }
+            ast::ItemKind::MacroDef(ref macro_def) => {
+                self.print_mac_def(macro_def, &item.ident, &item.span, |state| {
+                    state.print_visibility(&item.vis)
+                });
+            }
+        }
+        self.ann.post(self, AnnNode::Item(item))
+    }
+
+    fn print_enum_def(
+        &mut self,
+        enum_definition: &ast::EnumDef,
+        generics: &ast::Generics,
+        ident: Ident,
+        span: rustc_span::Span,
+        visibility: &ast::Visibility,
+    ) {
+        self.head(visibility_qualified(visibility, "enum"));
+        self.print_ident(ident);
+        self.print_generic_params(&generics.params);
+        self.print_where_clause(&generics.where_clause);
+        self.space();
+        self.print_variants(&enum_definition.variants, span)
+    }
+
+    fn print_variants(&mut self, variants: &[ast::Variant], span: rustc_span::Span) {
+        self.bopen();
+        for v in variants {
+            self.space_if_not_bol();
+            self.maybe_print_comment(v.span.lo());
+            self.print_outer_attributes(&v.attrs);
+            self.ibox(INDENT_UNIT);
+            self.print_variant(v);
+            self.word(",");
+            self.end();
+            self.maybe_print_trailing_comment(v.span, None);
+        }
+        let empty = variants.is_empty();
+        self.bclose(span, empty)
+    }
+
+    crate fn print_visibility(&mut self, vis: &ast::Visibility) {
+        match vis.kind {
+            ast::VisibilityKind::Public => self.word_nbsp("pub"),
+            ast::VisibilityKind::Crate(sugar) => match sugar {
+                ast::CrateSugar::PubCrate => self.word_nbsp("pub(crate)"),
+                ast::CrateSugar::JustCrate => self.word_nbsp("crate"),
+            },
+            ast::VisibilityKind::Restricted { ref path, .. } => {
+                let path = Self::to_string(|s| s.print_path(path, false, 0));
+                if path == "self" || path == "super" {
+                    self.word_nbsp(format!("pub({})", path))
+                } else {
+                    self.word_nbsp(format!("pub(in {})", path))
+                }
+            }
+            ast::VisibilityKind::Inherited => {}
+        }
+    }
+
+    fn print_defaultness(&mut self, defaultness: ast::Defaultness) {
+        if let ast::Defaultness::Default(_) = defaultness {
+            self.word_nbsp("default");
+        }
+    }
+
+    fn print_record_struct_body(&mut self, fields: &[ast::FieldDef], span: rustc_span::Span) {
+        self.nbsp();
+        self.bopen();
+
+        let empty = fields.is_empty();
+        if !empty {
+            self.hardbreak_if_not_bol();
+
+            for field in fields {
+                self.hardbreak_if_not_bol();
+                self.maybe_print_comment(field.span.lo());
+                self.print_outer_attributes(&field.attrs);
+                self.print_visibility(&field.vis);
+                self.print_ident(field.ident.unwrap());
+                self.word_nbsp(":");
+                self.print_type(&field.ty);
+                self.word(",");
+            }
+        }
+
+        self.bclose(span, empty);
+    }
+
+    fn print_struct(
+        &mut self,
+        struct_def: &ast::VariantData,
+        generics: &ast::Generics,
+        ident: Ident,
+        span: rustc_span::Span,
+        print_finalizer: bool,
+    ) {
+        self.print_ident(ident);
+        self.print_generic_params(&generics.params);
+        match struct_def {
+            ast::VariantData::Tuple(..) | ast::VariantData::Unit(..) => {
+                if let ast::VariantData::Tuple(..) = struct_def {
+                    self.popen();
+                    self.commasep(Inconsistent, struct_def.fields(), |s, field| {
+                        s.maybe_print_comment(field.span.lo());
+                        s.print_outer_attributes(&field.attrs);
+                        s.print_visibility(&field.vis);
+                        s.print_type(&field.ty)
+                    });
+                    self.pclose();
+                }
+                self.print_where_clause(&generics.where_clause);
+                if print_finalizer {
+                    self.word(";");
+                }
+                self.end();
+                self.end(); // Close the outer-box.
+            }
+            ast::VariantData::Struct(ref fields, ..) => {
+                self.print_where_clause(&generics.where_clause);
+                self.print_record_struct_body(fields, span);
+            }
+        }
+    }
+
+    crate fn print_variant(&mut self, v: &ast::Variant) {
+        self.head("");
+        self.print_visibility(&v.vis);
+        let generics = ast::Generics::default();
+        self.print_struct(&v.data, &generics, v.ident, v.span, false);
+        if let Some(ref d) = v.disr_expr {
+            self.space();
+            self.word_space("=");
+            self.print_expr(&d.value)
+        }
+    }
+
+    fn print_assoc_item(&mut self, item: &ast::AssocItem) {
+        let ast::Item { id, span, ident, ref attrs, ref kind, ref vis, tokens: _ } = *item;
+        self.ann.pre(self, AnnNode::SubItem(id));
+        self.hardbreak_if_not_bol();
+        self.maybe_print_comment(span.lo());
+        self.print_outer_attributes(attrs);
+        match kind {
+            ast::AssocItemKind::Fn(box ast::Fn { defaultness, sig, generics, body }) => {
+                self.print_fn_full(sig, ident, generics, vis, *defaultness, body.as_deref(), attrs);
+            }
+            ast::AssocItemKind::Const(def, ty, body) => {
+                self.print_item_const(ident, None, ty, body.as_deref(), vis, *def);
+            }
+            ast::AssocItemKind::TyAlias(box ast::TyAlias { defaultness, generics, bounds, ty }) => {
+                self.print_associated_type(
+                    ident,
+                    generics,
+                    bounds,
+                    ty.as_deref(),
+                    vis,
+                    *defaultness,
+                );
+            }
+            ast::AssocItemKind::MacCall(m) => {
+                self.print_mac(m);
+                if m.args.need_semicolon() {
+                    self.word(";");
+                }
+            }
+        }
+        self.ann.post(self, AnnNode::SubItem(id))
+    }
+
+    fn print_fn_full(
+        &mut self,
+        sig: &ast::FnSig,
+        name: Ident,
+        generics: &ast::Generics,
+        vis: &ast::Visibility,
+        defaultness: ast::Defaultness,
+        body: Option<&ast::Block>,
+        attrs: &[ast::Attribute],
+    ) {
+        if body.is_some() {
+            self.head("");
+        }
+        self.print_visibility(vis);
+        self.print_defaultness(defaultness);
+        self.print_fn(&sig.decl, sig.header, Some(name), generics);
+        if let Some(body) = body {
+            self.nbsp();
+            self.print_block_with_attrs(body, attrs);
+        } else {
+            self.word(";");
+        }
+    }
+
+    crate fn print_fn(
+        &mut self,
+        decl: &ast::FnDecl,
+        header: ast::FnHeader,
+        name: Option<Ident>,
+        generics: &ast::Generics,
+    ) {
+        self.print_fn_header_info(header);
+        if let Some(name) = name {
+            self.nbsp();
+            self.print_ident(name);
+        }
+        self.print_generic_params(&generics.params);
+        self.print_fn_params_and_ret(decl, false);
+        self.print_where_clause(&generics.where_clause)
+    }
+
+    crate fn print_fn_params_and_ret(&mut self, decl: &ast::FnDecl, is_closure: bool) {
+        let (open, close) = if is_closure { ("|", "|") } else { ("(", ")") };
+        self.word(open);
+        self.commasep(Inconsistent, &decl.inputs, |s, param| s.print_param(param, is_closure));
+        self.word(close);
+        self.print_fn_ret_ty(&decl.output)
+    }
+
+    fn print_where_clause(&mut self, where_clause: &ast::WhereClause) {
+        if where_clause.predicates.is_empty() && !where_clause.has_where_token {
+            return;
+        }
+
+        self.space();
+        self.word_space("where");
+
+        for (i, predicate) in where_clause.predicates.iter().enumerate() {
+            if i != 0 {
+                self.word_space(",");
+            }
+
+            self.print_where_predicate(predicate);
+        }
+    }
+
+    pub fn print_where_predicate(&mut self, predicate: &ast::WherePredicate) {
+        match predicate {
+            ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate {
+                bound_generic_params,
+                bounded_ty,
+                bounds,
+                ..
+            }) => {
+                self.print_formal_generic_params(bound_generic_params);
+                self.print_type(bounded_ty);
+                self.print_type_bounds(":", bounds);
+            }
+            ast::WherePredicate::RegionPredicate(ast::WhereRegionPredicate {
+                lifetime,
+                bounds,
+                ..
+            }) => {
+                self.print_lifetime_bounds(*lifetime, bounds);
+            }
+            ast::WherePredicate::EqPredicate(ast::WhereEqPredicate { lhs_ty, rhs_ty, .. }) => {
+                self.print_type(lhs_ty);
+                self.space();
+                self.word_space("=");
+                self.print_type(rhs_ty);
+            }
+        }
+    }
+
+    fn print_use_tree(&mut self, tree: &ast::UseTree) {
+        match tree.kind {
+            ast::UseTreeKind::Simple(rename, ..) => {
+                self.print_path(&tree.prefix, false, 0);
+                if let Some(rename) = rename {
+                    self.space();
+                    self.word_space("as");
+                    self.print_ident(rename);
+                }
+            }
+            ast::UseTreeKind::Glob => {
+                if !tree.prefix.segments.is_empty() {
+                    self.print_path(&tree.prefix, false, 0);
+                    self.word("::");
+                }
+                self.word("*");
+            }
+            ast::UseTreeKind::Nested(ref items) => {
+                if tree.prefix.segments.is_empty() {
+                    self.word("{");
+                } else {
+                    self.print_path(&tree.prefix, false, 0);
+                    self.word("::{");
+                }
+                self.commasep(Inconsistent, &items, |this, &(ref tree, _)| {
+                    this.print_use_tree(tree)
+                });
+                self.word("}");
+            }
+        }
+    }
+}
diff --git a/compiler/rustc_codegen_ssa/src/mir/place.rs b/compiler/rustc_codegen_ssa/src/mir/place.rs
index 4b07ed1a1e6..c21d19a6227 100644
--- a/compiler/rustc_codegen_ssa/src/mir/place.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/place.rs
@@ -429,87 +429,78 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         let cx = self.cx;
         let tcx = self.cx.tcx();
 
-        let result = match place_ref {
-            mir::PlaceRef { local, projection: [] } => match self.locals[local] {
-                LocalRef::Place(place) => {
-                    return place;
-                }
-                LocalRef::UnsizedPlace(place) => {
-                    return bx.load_operand(place).deref(cx);
-                }
-                LocalRef::Operand(..) => {
+        let mut base = 0;
+        let mut cg_base = match self.locals[place_ref.local] {
+            LocalRef::Place(place) => place,
+            LocalRef::UnsizedPlace(place) => bx.load_operand(place).deref(cx),
+            LocalRef::Operand(..) => {
+                if let Some(elem) = place_ref
+                    .projection
+                    .iter()
+                    .enumerate()
+                    .find(|elem| matches!(elem.1, mir::ProjectionElem::Deref))
+                {
+                    base = elem.0 + 1;
+                    self.codegen_consume(
+                        bx,
+                        mir::PlaceRef { projection: &place_ref.projection[..elem.0], ..place_ref },
+                    )
+                    .deref(bx.cx())
+                } else {
                     bug!("using operand local {:?} as place", place_ref);
                 }
-            },
-            mir::PlaceRef { local, projection: [proj_base @ .., mir::ProjectionElem::Deref] } => {
-                // Load the pointer from its location.
-                self.codegen_consume(bx, mir::PlaceRef { local, projection: proj_base })
-                    .deref(bx.cx())
             }
-            mir::PlaceRef { local, projection: &[ref proj_base @ .., elem] } => {
-                // FIXME turn this recursion into iteration
-                let cg_base =
-                    self.codegen_place(bx, mir::PlaceRef { local, projection: proj_base });
-
-                match elem {
-                    mir::ProjectionElem::Deref => bug!(),
-                    mir::ProjectionElem::Field(ref field, _) => {
-                        cg_base.project_field(bx, field.index())
-                    }
-                    mir::ProjectionElem::Index(index) => {
-                        let index = &mir::Operand::Copy(mir::Place::from(index));
-                        let index = self.codegen_operand(bx, index);
-                        let llindex = index.immediate();
-                        cg_base.project_index(bx, llindex)
-                    }
-                    mir::ProjectionElem::ConstantIndex {
-                        offset,
-                        from_end: false,
-                        min_length: _,
-                    } => {
-                        let lloffset = bx.cx().const_usize(offset as u64);
-                        cg_base.project_index(bx, lloffset)
-                    }
-                    mir::ProjectionElem::ConstantIndex {
-                        offset,
-                        from_end: true,
-                        min_length: _,
-                    } => {
-                        let lloffset = bx.cx().const_usize(offset as u64);
-                        let lllen = cg_base.len(bx.cx());
-                        let llindex = bx.sub(lllen, lloffset);
-                        cg_base.project_index(bx, llindex)
-                    }
-                    mir::ProjectionElem::Subslice { from, to, from_end } => {
-                        let mut subslice =
-                            cg_base.project_index(bx, bx.cx().const_usize(from as u64));
-                        let projected_ty =
-                            PlaceTy::from_ty(cg_base.layout.ty).projection_ty(tcx, elem).ty;
-                        subslice.layout = bx.cx().layout_of(self.monomorphize(projected_ty));
-
-                        if subslice.layout.is_unsized() {
-                            assert!(from_end, "slice subslices should be `from_end`");
-                            subslice.llextra = Some(bx.sub(
-                                cg_base.llextra.unwrap(),
-                                bx.cx().const_usize((from as u64) + (to as u64)),
-                            ));
-                        }
-
-                        // Cast the place pointer type to the new
-                        // array or slice type (`*[%_; new_len]`).
-                        subslice.llval = bx.pointercast(
-                            subslice.llval,
-                            bx.cx().type_ptr_to(bx.cx().backend_type(subslice.layout)),
-                        );
-
-                        subslice
+        };
+        for elem in place_ref.projection[base..].iter() {
+            cg_base = match elem.clone() {
+                mir::ProjectionElem::Deref => bx.load_operand(cg_base).deref(bx.cx()),
+                mir::ProjectionElem::Field(ref field, _) => {
+                    cg_base.project_field(bx, field.index())
+                }
+                mir::ProjectionElem::Index(index) => {
+                    let index = &mir::Operand::Copy(mir::Place::from(index));
+                    let index = self.codegen_operand(bx, index);
+                    let llindex = index.immediate();
+                    cg_base.project_index(bx, llindex)
+                }
+                mir::ProjectionElem::ConstantIndex { offset, from_end: false, min_length: _ } => {
+                    let lloffset = bx.cx().const_usize(offset as u64);
+                    cg_base.project_index(bx, lloffset)
+                }
+                mir::ProjectionElem::ConstantIndex { offset, from_end: true, min_length: _ } => {
+                    let lloffset = bx.cx().const_usize(offset as u64);
+                    let lllen = cg_base.len(bx.cx());
+                    let llindex = bx.sub(lllen, lloffset);
+                    cg_base.project_index(bx, llindex)
+                }
+                mir::ProjectionElem::Subslice { from, to, from_end } => {
+                    let mut subslice = cg_base.project_index(bx, bx.cx().const_usize(from as u64));
+                    let projected_ty =
+                        PlaceTy::from_ty(cg_base.layout.ty).projection_ty(tcx, elem.clone()).ty;
+                    subslice.layout = bx.cx().layout_of(self.monomorphize(projected_ty));
+
+                    if subslice.layout.is_unsized() {
+                        assert!(from_end, "slice subslices should be `from_end`");
+                        subslice.llextra = Some(bx.sub(
+                            cg_base.llextra.unwrap(),
+                            bx.cx().const_usize((from as u64) + (to as u64)),
+                        ));
                     }
-                    mir::ProjectionElem::Downcast(_, v) => cg_base.project_downcast(bx, v),
+
+                    // Cast the place pointer type to the new
+                    // array or slice type (`*[%_; new_len]`).
+                    subslice.llval = bx.pointercast(
+                        subslice.llval,
+                        bx.cx().type_ptr_to(bx.cx().backend_type(subslice.layout)),
+                    );
+
+                    subslice
                 }
-            }
-        };
-        debug!("codegen_place(place={:?}) => {:?}", place_ref, result);
-        result
+                mir::ProjectionElem::Downcast(_, v) => cg_base.project_downcast(bx, v),
+            };
+        }
+        debug!("codegen_place(place={:?}) => {:?}", place_ref, cg_base);
+        cg_base
     }
 
     pub fn monomorphized_place_ty(&self, place_ref: mir::PlaceRef<'tcx>) -> Ty<'tcx> {
diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs
index 47010ea3ab6..0b65a5ff3ec 100644
--- a/compiler/rustc_feature/src/active.rs
+++ b/compiler/rustc_feature/src/active.rs
@@ -415,7 +415,7 @@ declare_features! (
     // Allows setting the threshold for the `large_assignments` lint.
     (active, large_assignments, "1.52.0", Some(83518), None),
     /// Allows `if/while p && let q = r && ...` chains.
-    (incomplete, let_chains, "1.37.0", Some(53667), None),
+    (active, let_chains, "1.37.0", Some(53667), None),
     /// Allows `let...else` statements.
     (active, let_else, "1.56.0", Some(87335), None),
     /// Allows `#[link(..., cfg(..))]`.
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index 3f4bbdec315..48f39b26152 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -162,7 +162,7 @@ impl MirPhase {
 }
 
 /// Where a specific `mir::Body` comes from.
-#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 #[derive(HashStable, TyEncodable, TyDecodable, TypeFoldable)]
 pub struct MirSource<'tcx> {
     pub instance: InstanceDef<'tcx>,
@@ -1255,17 +1255,7 @@ pub enum AssertKind<O> {
     ResumedAfterPanic(GeneratorKind),
 }
 
-#[derive(
-    Clone,
-    Debug,
-    PartialEq,
-    PartialOrd,
-    TyEncodable,
-    TyDecodable,
-    Hash,
-    HashStable,
-    TypeFoldable
-)]
+#[derive(Clone, Debug, PartialEq, TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable)]
 pub enum InlineAsmOperand<'tcx> {
     In {
         reg: InlineAsmRegOrRegClass,
@@ -1747,7 +1737,7 @@ pub struct CopyNonOverlapping<'tcx> {
 
 /// A path to a value; something that can be evaluated without
 /// changing or disturbing program state.
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, HashStable)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, HashStable)]
 pub struct Place<'tcx> {
     pub local: Local,
 
@@ -2072,7 +2062,7 @@ pub struct SourceScopeLocalData {
 
 /// These are values that can appear inside an rvalue. They are intentionally
 /// limited to prevent rvalues from being nested in one another.
-#[derive(Clone, PartialEq, PartialOrd, TyEncodable, TyDecodable, Hash, HashStable)]
+#[derive(Clone, PartialEq, TyEncodable, TyDecodable, Hash, HashStable)]
 pub enum Operand<'tcx> {
     /// Copy: The value must be available for use afterwards.
     ///
@@ -2500,7 +2490,7 @@ impl<'tcx> Debug for Rvalue<'tcx> {
 /// this does not necessarily mean that they are `==` in Rust. In
 /// particular, one must be wary of `NaN`!
 
-#[derive(Clone, Copy, PartialEq, PartialOrd, TyEncodable, TyDecodable, Hash, HashStable)]
+#[derive(Clone, Copy, PartialEq, TyEncodable, TyDecodable, Hash, HashStable)]
 pub struct Constant<'tcx> {
     pub span: Span,
 
@@ -2514,7 +2504,7 @@ pub struct Constant<'tcx> {
     pub literal: ConstantKind<'tcx>,
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, TyEncodable, TyDecodable, Hash, HashStable, Debug)]
+#[derive(Clone, Copy, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable, Debug)]
 #[derive(Lift)]
 pub enum ConstantKind<'tcx> {
     /// This constant came from the type system
diff --git a/compiler/rustc_middle/src/thir.rs b/compiler/rustc_middle/src/thir.rs
index eef42666f2a..11dc69ab715 100644
--- a/compiler/rustc_middle/src/thir.rs
+++ b/compiler/rustc_middle/src/thir.rs
@@ -213,7 +213,7 @@ pub struct Expr<'tcx> {
 
 #[derive(Debug, HashStable)]
 pub enum ExprKind<'tcx> {
-    /// `Scope`s are used to explicitely mark destruction scopes,
+    /// `Scope`s are used to explicitly mark destruction scopes,
     /// and to track the `HirId` of the expressions within the scope.
     Scope {
         region_scope: region::Scope,
diff --git a/compiler/rustc_mir_build/src/build/expr/into.rs b/compiler/rustc_mir_build/src/build/expr/into.rs
index 43060ecfced..da8fbdbf3bc 100644
--- a/compiler/rustc_mir_build/src/build/expr/into.rs
+++ b/compiler/rustc_mir_build/src/build/expr/into.rs
@@ -90,17 +90,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 };
 
                 let join_block = this.cfg.start_new_block();
-                this.cfg.terminate(
-                    then_blk,
-                    source_info,
-                    TerminatorKind::Goto { target: join_block },
-                );
-                this.cfg.terminate(
-                    else_blk,
-                    source_info,
-                    TerminatorKind::Goto { target: join_block },
-                );
-
+                this.cfg.goto(then_blk, source_info, join_block);
+                this.cfg.goto(else_blk, source_info, join_block);
                 join_block.unit()
             }
             ExprKind::Let { expr, ref pat } => {
@@ -109,8 +100,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     this.lower_let_expr(block, &this.thir[expr], pat, scope, expr_span)
                 });
 
-                let join_block = this.cfg.start_new_block();
-
                 this.cfg.push_assign_constant(
                     true_block,
                     source_info,
@@ -133,6 +122,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     },
                 );
 
+                let join_block = this.cfg.start_new_block();
                 this.cfg.goto(true_block, source_info, join_block);
                 this.cfg.goto(false_block, source_info, join_block);
                 join_block.unit()
diff --git a/compiler/rustc_mir_build/src/build/matches/mod.rs b/compiler/rustc_mir_build/src/build/matches/mod.rs
index e3a05e01ea8..85950d82419 100644
--- a/compiler/rustc_mir_build/src/build/matches/mod.rs
+++ b/compiler/rustc_mir_build/src/build/matches/mod.rs
@@ -47,6 +47,25 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let expr_span = expr.span;
 
         match expr.kind {
+            ExprKind::LogicalOp { op: LogicalOp::And, lhs, rhs } => {
+                let lhs_then_block = unpack!(this.then_else_break(
+                    block,
+                    &this.thir[lhs],
+                    temp_scope_override,
+                    break_scope,
+                    variable_scope_span,
+                ));
+
+                let rhs_then_block = unpack!(this.then_else_break(
+                    lhs_then_block,
+                    &this.thir[rhs],
+                    temp_scope_override,
+                    break_scope,
+                    variable_scope_span,
+                ));
+
+                rhs_then_block.unit()
+            }
             ExprKind::Scope { region_scope, lint_level, value } => {
                 let region_scope = (region_scope, this.source_info(expr_span));
                 this.in_scope(region_scope, lint_level, |this| {
diff --git a/compiler/rustc_mir_build/src/build/scope.rs b/compiler/rustc_mir_build/src/build/scope.rs
index fc46c54c2fc..84d6c1d2db8 100644
--- a/compiler/rustc_mir_build/src/build/scope.rs
+++ b/compiler/rustc_mir_build/src/build/scope.rs
@@ -498,7 +498,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     ///
     /// if let Some(x) = a && let Some(y) = b && let Some(z) = c { ... }
     ///
-    /// there are three possible ways the condition can be false and we may have
+    /// There are three possible ways the condition can be false and we may have
     /// to drop `x`, `x` and `y`, or neither depending on which binding fails.
     /// To handle this correctly we use a `DropTree` in a similar way to a
     /// `loop` expression and 'break' out on all of the 'else' paths.
diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs
index 750677f161e..a43388808cd 100644
--- a/compiler/rustc_mir_build/src/thir/cx/expr.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs
@@ -315,7 +315,6 @@ impl<'tcx> Cx<'tcx> {
                             lhs: self.mirror_expr(lhs),
                             rhs: self.mirror_expr(rhs),
                         },
-
                         _ => {
                             let op = bin_op(op.node);
                             ExprKind::Binary {
diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
index 868dd195f3a..34204c3852a 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
@@ -17,6 +17,7 @@ use rustc_session::lint::builtin::{
     BINDINGS_WITH_VARIANT_NAME, IRREFUTABLE_LET_PATTERNS, UNREACHABLE_PATTERNS,
 };
 use rustc_session::Session;
+use rustc_span::source_map::Spanned;
 use rustc_span::{DesugaringKind, ExpnKind, Span};
 
 crate fn check_match(tcx: TyCtxt<'_>, def_id: DefId) {
@@ -445,6 +446,10 @@ fn check_let_reachability<'p, 'tcx>(
     pat: &'p DeconstructedPat<'p, 'tcx>,
     span: Span,
 ) {
+    if is_let_chain(cx.tcx, pat_id) {
+        return;
+    }
+
     let arms = [MatchArm { pat, hir_id: pat_id, has_guard: false }];
     let report = compute_match_usefulness(&cx, &arms, pat_id, pat.ty());
 
@@ -764,8 +769,11 @@ pub enum LetSource {
 
 fn let_source(tcx: TyCtxt<'_>, pat_id: HirId) -> LetSource {
     let hir = tcx.hir();
+
     let parent = hir.get_parent_node(pat_id);
-    match hir.get(parent) {
+    let parent_node = hir.get(parent);
+
+    match parent_node {
         hir::Node::Arm(hir::Arm {
             guard: Some(hir::Guard::IfLet(&hir::Pat { hir_id, .. }, _)),
             ..
@@ -780,6 +788,7 @@ fn let_source(tcx: TyCtxt<'_>, pat_id: HirId) -> LetSource {
         }
         _ => {}
     }
+
     let parent_parent = hir.get_parent_node(parent);
     let parent_parent_node = hir.get(parent_parent);
 
@@ -792,12 +801,30 @@ fn let_source(tcx: TyCtxt<'_>, pat_id: HirId) -> LetSource {
         ..
     }) = parent_parent_parent_parent_node
     {
-        LetSource::WhileLet
-    } else if let hir::Node::Expr(hir::Expr { kind: hir::ExprKind::If { .. }, .. }) =
-        parent_parent_node
-    {
-        LetSource::IfLet
-    } else {
-        LetSource::GenericLet
+        return LetSource::WhileLet;
+    }
+
+    if let hir::Node::Expr(hir::Expr { kind: hir::ExprKind::If(..), .. }) = parent_parent_node {
+        return LetSource::IfLet;
     }
+
+    LetSource::GenericLet
+}
+
+// Since this function is called within a let context, it is reasonable to assume that any parent
+// `&&` infers a let chain
+fn is_let_chain(tcx: TyCtxt<'_>, pat_id: HirId) -> bool {
+    let hir = tcx.hir();
+    let parent = hir.get_parent_node(pat_id);
+    let parent_parent = hir.get_parent_node(parent);
+    matches!(
+        hir.get(parent_parent),
+        hir::Node::Expr(
+            hir::Expr {
+                kind: hir::ExprKind::Binary(Spanned { node: hir::BinOpKind::And, .. }, ..),
+                ..
+            },
+            ..
+        )
+    )
 }
diff --git a/compiler/rustc_passes/src/dead.rs b/compiler/rustc_passes/src/dead.rs
index 4cca7142449..7f15aacc532 100644
--- a/compiler/rustc_passes/src/dead.rs
+++ b/compiler/rustc_passes/src/dead.rs
@@ -3,6 +3,7 @@
 // from live codes are live, and everything else is dead.
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_errors::pluralize;
 use rustc_hir as hir;
 use rustc_hir::def::{CtorOf, DefKind, Res};
 use rustc_hir::def_id::{DefId, LocalDefId};
@@ -15,6 +16,7 @@ use rustc_middle::middle::privacy;
 use rustc_middle::ty::{self, DefIdTree, TyCtxt};
 use rustc_session::lint;
 use rustc_span::symbol::{sym, Symbol};
+use rustc_span::Span;
 use std::mem;
 
 // Any local node that may call something in its body block should be
@@ -47,6 +49,10 @@ struct MarkSymbolVisitor<'tcx> {
     ignore_variant_stack: Vec<DefId>,
     // maps from tuple struct constructors to tuple struct items
     struct_constructors: FxHashMap<LocalDefId, LocalDefId>,
+    // maps from ADTs to ignored derived traits (e.g. Debug and Clone)
+    // and the span of their respective impl (i.e., part of the derive
+    // macro)
+    ignored_derived_traits: FxHashMap<DefId, Vec<(Span, DefId)>>,
 }
 
 impl<'tcx> MarkSymbolVisitor<'tcx> {
@@ -242,7 +248,7 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
     /// Automatically generated items marked with `rustc_trivial_field_reads`
     /// will be ignored for the purposes of dead code analysis (see PR #85200
     /// for discussion).
-    fn should_ignore_item(&self, def_id: DefId) -> bool {
+    fn should_ignore_item(&mut self, def_id: DefId) -> bool {
         if let Some(impl_of) = self.tcx.impl_of_method(def_id) {
             if !self.tcx.has_attr(impl_of, sym::automatically_derived) {
                 return false;
@@ -250,6 +256,16 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
 
             if let Some(trait_of) = self.tcx.trait_id_of_impl(impl_of) {
                 if self.tcx.has_attr(trait_of, sym::rustc_trivial_field_reads) {
+                    let trait_ref = self.tcx.impl_trait_ref(impl_of).unwrap();
+                    if let ty::Adt(adt_def, _) = trait_ref.self_ty().kind() {
+                        let impl_span = self.tcx.def_span(impl_of);
+                        if let Some(v) = self.ignored_derived_traits.get_mut(&adt_def.did) {
+                            v.push((impl_span, trait_of));
+                        } else {
+                            self.ignored_derived_traits
+                                .insert(adt_def.did, vec![(impl_span, trait_of)]);
+                        }
+                    }
                     return true;
                 }
             }
@@ -571,7 +587,7 @@ fn create_and_seed_worklist<'tcx>(
 fn find_live<'tcx>(
     tcx: TyCtxt<'tcx>,
     access_levels: &privacy::AccessLevels,
-) -> FxHashSet<LocalDefId> {
+) -> (FxHashSet<LocalDefId>, FxHashMap<DefId, Vec<(Span, DefId)>>) {
     let (worklist, struct_constructors) = create_and_seed_worklist(tcx, access_levels);
     let mut symbol_visitor = MarkSymbolVisitor {
         worklist,
@@ -584,14 +600,16 @@ fn find_live<'tcx>(
         pub_visibility: false,
         ignore_variant_stack: vec![],
         struct_constructors,
+        ignored_derived_traits: FxHashMap::default(),
     };
     symbol_visitor.mark_live_symbols();
-    symbol_visitor.live_symbols
+    (symbol_visitor.live_symbols, symbol_visitor.ignored_derived_traits)
 }
 
 struct DeadVisitor<'tcx> {
     tcx: TyCtxt<'tcx>,
     live_symbols: FxHashSet<LocalDefId>,
+    ignored_derived_traits: FxHashMap<DefId, Vec<(Span, DefId)>>,
 }
 
 impl<'tcx> DeadVisitor<'tcx> {
@@ -660,7 +678,37 @@ impl<'tcx> DeadVisitor<'tcx> {
             self.tcx.struct_span_lint_hir(lint::builtin::DEAD_CODE, id, span, |lint| {
                 let def_id = self.tcx.hir().local_def_id(id);
                 let descr = self.tcx.def_kind(def_id).descr(def_id.to_def_id());
-                lint.build(&format!("{} is never {}: `{}`", descr, participle, name)).emit()
+                let mut err = lint.build(&format!("{} is never {}: `{}`", descr, participle, name));
+                let hir = self.tcx.hir();
+                if let Some(encl_scope) = hir.get_enclosing_scope(id) {
+                    if let Some(encl_def_id) = hir.opt_local_def_id(encl_scope) {
+                        if let Some(ign_traits) =
+                            self.ignored_derived_traits.get(&encl_def_id.to_def_id())
+                        {
+                            let traits_str = ign_traits
+                                .iter()
+                                .map(|(_, t)| format!("`{}`", self.tcx.item_name(*t)))
+                                .collect::<Vec<_>>()
+                                .join(" and ");
+                            let plural_s = pluralize!(ign_traits.len());
+                            let article = if ign_traits.len() > 1 { "" } else { "a " };
+                            let is_are = if ign_traits.len() > 1 { "these are" } else { "this is" };
+                            let msg = format!(
+                                "`{}` has {}derived impl{} for the trait{} {}, but {} \
+                                 intentionally ignored during dead code analysis",
+                                self.tcx.item_name(encl_def_id.to_def_id()),
+                                article,
+                                plural_s,
+                                plural_s,
+                                traits_str,
+                                is_are
+                            );
+                            let multispan = ign_traits.iter().map(|(s, _)| *s).collect::<Vec<_>>();
+                            err.span_note(multispan, &msg);
+                        }
+                    }
+                }
+                err.emit();
             });
         }
     }
@@ -790,7 +838,7 @@ impl<'tcx> Visitor<'tcx> for DeadVisitor<'tcx> {
 
 pub fn check_crate(tcx: TyCtxt<'_>) {
     let access_levels = &tcx.privacy_access_levels(());
-    let live_symbols = find_live(tcx, access_levels);
-    let mut visitor = DeadVisitor { tcx, live_symbols };
+    let (live_symbols, ignored_derived_traits) = find_live(tcx, access_levels);
+    let mut visitor = DeadVisitor { tcx, live_symbols, ignored_derived_traits };
     tcx.hir().walk_toplevel_module(&mut visitor);
 }
diff --git a/library/alloc/src/slice.rs b/library/alloc/src/slice.rs
index 8853577371a..a5c4140e313 100644
--- a/library/alloc/src/slice.rs
+++ b/library/alloc/src/slice.rs
@@ -375,7 +375,10 @@ impl<T> [T] {
 
     /// Sorts the slice with a key extraction function.
     ///
-    /// During sorting, the key function is called only once per element.
+    /// During sorting, the key function is called at most once per element, by using
+    /// temporary storage to remember the results of key evaluation.
+    /// The order of calls to the key function is unspecified and may change in future versions
+    /// of the standard library.
     ///
     /// This sort is stable (i.e., does not reorder equal elements) and *O*(*m* \* *n* + *n* \* log(*n*))
     /// worst-case, where the key function is *O*(*m*).
diff --git a/library/core/src/option.rs b/library/core/src/option.rs
index 8adfb6f4bcf..611f4ab38ab 100644
--- a/library/core/src/option.rs
+++ b/library/core/src/option.rs
@@ -551,6 +551,29 @@ impl<T> Option<T> {
         matches!(*self, Some(_))
     }
 
+    /// Returns `true` if the option is a [`Some`] wrapping a value matching the predicate.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(is_some_with)]
+    ///
+    /// let x: Option<u32> = Some(2);
+    /// assert_eq!(x.is_some_with(|&x| x > 1), true);
+    ///
+    /// let x: Option<u32> = Some(0);
+    /// assert_eq!(x.is_some_with(|&x| x > 1), false);
+    ///
+    /// let x: Option<u32> = None;
+    /// assert_eq!(x.is_some_with(|&x| x > 1), false);
+    /// ```
+    #[must_use]
+    #[inline]
+    #[unstable(feature = "is_some_with", issue = "93050")]
+    pub fn is_some_with(&self, f: impl FnOnce(&T) -> bool) -> bool {
+        matches!(self, Some(x) if f(x))
+    }
+
     /// Returns `true` if the option is a [`None`] value.
     ///
     /// # Examples
diff --git a/library/core/src/result.rs b/library/core/src/result.rs
index b8f0d84746c..fbd6d419236 100644
--- a/library/core/src/result.rs
+++ b/library/core/src/result.rs
@@ -542,6 +542,29 @@ impl<T, E> Result<T, E> {
         matches!(*self, Ok(_))
     }
 
+    /// Returns `true` if the result is [`Ok`] wrapping a value matching the predicate.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(is_some_with)]
+    ///
+    /// let x: Result<u32, &str> = Ok(2);
+    /// assert_eq!(x.is_ok_with(|&x| x > 1), true);
+    ///
+    /// let x: Result<u32, &str> = Ok(0);
+    /// assert_eq!(x.is_ok_with(|&x| x > 1), false);
+    ///
+    /// let x: Result<u32, &str> = Err("hey");
+    /// assert_eq!(x.is_ok_with(|&x| x > 1), false);
+    /// ```
+    #[must_use]
+    #[inline]
+    #[unstable(feature = "is_some_with", issue = "93050")]
+    pub fn is_ok_with(&self, f: impl FnOnce(&T) -> bool) -> bool {
+        matches!(self, Ok(x) if f(x))
+    }
+
     /// Returns `true` if the result is [`Err`].
     ///
     /// # Examples
@@ -563,6 +586,30 @@ impl<T, E> Result<T, E> {
         !self.is_ok()
     }
 
+    /// Returns `true` if the result is [`Err`] wrapping a value matching the predicate.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(is_some_with)]
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// let x: Result<u32, Error> = Err(Error::new(ErrorKind::NotFound, "!"));
+    /// assert_eq!(x.is_err_with(|x| x.kind() == ErrorKind::NotFound), true);
+    ///
+    /// let x: Result<u32, Error> = Err(Error::new(ErrorKind::PermissionDenied, "!"));
+    /// assert_eq!(x.is_err_with(|x| x.kind() == ErrorKind::NotFound), false);
+    ///
+    /// let x: Result<u32, Error> = Ok(123);
+    /// assert_eq!(x.is_err_with(|x| x.kind() == ErrorKind::NotFound), false);
+    /// ```
+    #[must_use]
+    #[inline]
+    #[unstable(feature = "is_some_with", issue = "93050")]
+    pub fn is_err_with(&self, f: impl FnOnce(&E) -> bool) -> bool {
+        matches!(self, Err(x) if f(x))
+    }
+
     /////////////////////////////////////////////////////////////////////////
     // Adapter for each variant
     /////////////////////////////////////////////////////////////////////////
diff --git a/library/std/src/ffi/c_str.rs b/library/std/src/ffi/c_str.rs
index 9c1b79d6966..d859bff1a45 100644
--- a/library/std/src/ffi/c_str.rs
+++ b/library/std/src/ffi/c_str.rs
@@ -373,38 +373,61 @@ impl CString {
     /// the position of the nul byte.
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn new<T: Into<Vec<u8>>>(t: T) -> Result<CString, NulError> {
-        trait SpecIntoVec {
-            fn into_vec(self) -> Vec<u8>;
+        trait SpecNewImpl {
+            fn spec_new_impl(self) -> Result<CString, NulError>;
         }
-        impl<T: Into<Vec<u8>>> SpecIntoVec for T {
-            default fn into_vec(self) -> Vec<u8> {
-                self.into()
+
+        impl<T: Into<Vec<u8>>> SpecNewImpl for T {
+            default fn spec_new_impl(self) -> Result<CString, NulError> {
+                let bytes: Vec<u8> = self.into();
+                match memchr::memchr(0, &bytes) {
+                    Some(i) => Err(NulError(i, bytes)),
+                    None => Ok(unsafe { CString::from_vec_unchecked(bytes) }),
+                }
             }
         }
-        // Specialization for avoiding reallocation.
-        impl SpecIntoVec for &'_ [u8] {
-            fn into_vec(self) -> Vec<u8> {
-                let mut v = Vec::with_capacity(self.len() + 1);
-                v.extend(self);
-                v
+
+        // Specialization for avoiding reallocation
+        #[inline(always)] // Without that it is not inlined into specializations
+        fn spec_new_impl_bytes(bytes: &[u8]) -> Result<CString, NulError> {
+            // We cannot have such large slice that we would overflow here
+            // but using `checked_add` allows LLVM to assume that capacity never overflows
+            // and generate twice shorter code.
+            // `saturating_add` doesn't help for some reason.
+            let capacity = bytes.len().checked_add(1).unwrap();
+
+            // Allocate before validation to avoid duplication of allocation code.
+            // We still need to allocate and copy memory even if we get an error.
+            let mut buffer = Vec::with_capacity(capacity);
+            buffer.extend(bytes);
+
+            // Check memory of self instead of new buffer.
+            // This allows better optimizations if lto enabled.
+            match memchr::memchr(0, bytes) {
+                Some(i) => Err(NulError(i, buffer)),
+                None => Ok(unsafe { CString::from_vec_unchecked(buffer) }),
             }
         }
-        impl SpecIntoVec for &'_ str {
-            fn into_vec(self) -> Vec<u8> {
-                let mut v = Vec::with_capacity(self.len() + 1);
-                v.extend(self.as_bytes());
-                v
+
+        impl SpecNewImpl for &'_ [u8] {
+            fn spec_new_impl(self) -> Result<CString, NulError> {
+                spec_new_impl_bytes(self)
             }
         }
 
-        Self::_new(SpecIntoVec::into_vec(t))
-    }
+        impl SpecNewImpl for &'_ str {
+            fn spec_new_impl(self) -> Result<CString, NulError> {
+                spec_new_impl_bytes(self.as_bytes())
+            }
+        }
 
-    fn _new(bytes: Vec<u8>) -> Result<CString, NulError> {
-        match memchr::memchr(0, &bytes) {
-            Some(i) => Err(NulError(i, bytes)),
-            None => Ok(unsafe { CString::from_vec_unchecked(bytes) }),
+        impl SpecNewImpl for &'_ mut [u8] {
+            fn spec_new_impl(self) -> Result<CString, NulError> {
+                spec_new_impl_bytes(self)
+            }
         }
+
+        t.spec_new_impl()
     }
 
     /// Creates a C-compatible string by consuming a byte vector,
diff --git a/src/doc/book b/src/doc/book
-Subproject d3740fb7aad0ea4a80ae20f64dee3a8cfc0c5c3
+Subproject f17df27fc14696912c48b8b7a7a8fa49e648088
diff --git a/src/doc/nomicon b/src/doc/nomicon
-Subproject c05c452b36358821bf4122f9c418674edd1d713
+Subproject 66d097d3d80e8f88c288c6879c7c2b909ecf8ad
diff --git a/src/doc/reference b/src/doc/reference
-Subproject f8ba2f12df60ee19b96de24ae5b73af3de8a446
+Subproject 4dee6eb63d728ffb9e7a2ed443e9ada9275c69d
diff --git a/src/doc/rustc-dev-guide b/src/doc/rustc-dev-guide
-Subproject 875464457c4104686faf667f47848aa7b0f0a74
+Subproject 78dd6a4684cf8d6b72275fab6d0429ea40b6633
diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index dbc068ce6b1..44a9a571fa1 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -148,8 +148,6 @@ h1.fqn {
 }
 .main-heading {
 	display: flex;
-	border-bottom: 1px dashed #DDDDDD;
-	padding-bottom: 6px;
 	margin-bottom: 15px;
 
 	/* workaround to keep flex from breaking below 700 px width due to the float: right on the nav
@@ -785,7 +783,6 @@ nav.sub {
 
 nav.sub {
 	flex-grow: 1;
-	padding-bottom: 10px;
 	margin-bottom: 25px;
 }
 .source nav.sub {
diff --git a/src/librustdoc/html/static/css/themes/ayu.css b/src/librustdoc/html/static/css/themes/ayu.css
index 82a2be67ceb..69097b81b9f 100644
--- a/src/librustdoc/html/static/css/themes/ayu.css
+++ b/src/librustdoc/html/static/css/themes/ayu.css
@@ -194,9 +194,6 @@ pre, .rustdoc.source .example-wrap {
 pre.rust .comment { color: #788797; }
 pre.rust .doccomment { color: #a1ac88; }
 
-nav:not(.sidebar) {
-	border-bottom-color: #424c57;
-}
 nav.main .current {
 	border-top-color: #5c6773;
 	border-bottom-color: #5c6773;
diff --git a/src/librustdoc/html/static/css/themes/dark.css b/src/librustdoc/html/static/css/themes/dark.css
index 761bf50dd36..39165b2fc05 100644
--- a/src/librustdoc/html/static/css/themes/dark.css
+++ b/src/librustdoc/html/static/css/themes/dark.css
@@ -151,9 +151,6 @@ a.result-keyword:focus { background-color: #884719; }
 pre.rust .comment { color: #8d8d8b; }
 pre.rust .doccomment { color: #8ca375; }
 
-nav:not(.sidebar) {
-	border-bottom-color: #4e4e4e;
-}
 nav.main .current {
 	border-top-color: #eee;
 	border-bottom-color: #eee;
diff --git a/src/librustdoc/html/static/css/themes/light.css b/src/librustdoc/html/static/css/themes/light.css
index 7cca7d4004b..448c9ac603c 100644
--- a/src/librustdoc/html/static/css/themes/light.css
+++ b/src/librustdoc/html/static/css/themes/light.css
@@ -148,9 +148,6 @@ a.result-keyword:focus { background-color: #afc6e4; }
 .content .fnname { color: #AD7C37; }
 .content span.keyword, .content a.keyword, .block a.current.keyword { color: #3873AD; }
 
-nav:not(.sidebar) {
-	border-bottom-color: #e0e0e0;
-}
 nav.main .current {
 	border-top-color: #000;
 	border-bottom-color: #000;
diff --git a/src/test/rustdoc-gui/headings.goml b/src/test/rustdoc-gui/headings.goml
index 34ff2de3a9b..48e0156f1b8 100644
--- a/src/test/rustdoc-gui/headings.goml
+++ b/src/test/rustdoc-gui/headings.goml
@@ -15,7 +15,6 @@
 goto: file://|DOC_PATH|/test_docs/struct.HeavilyDocumentedStruct.html
 
 assert-css: ("h1.fqn", {"font-size": "24px"})
-assert-css: (".main-heading", {"border-bottom-width": "1px"})
 
 assert-css: ("h2#top-doc-prose-title", {"font-size": "20.8px"})
 assert-css: ("h2#top-doc-prose-title", {"border-bottom-width": "1px"})
@@ -55,7 +54,6 @@ assert-css: ("h6#sub-sub-heading-for-struct-impl-item-doc", {"font-size": "15.2p
 goto: file://|DOC_PATH|/test_docs/enum.HeavilyDocumentedEnum.html
 
 assert-css: ("h1.fqn", {"font-size": "24px"})
-assert-css: (".main-heading", {"border-bottom-width": "1px"})
 
 assert-css: ("h2#top-doc-prose-title", {"font-size": "20.8px"})
 assert-css: ("h2#top-doc-prose-title", {"border-bottom-width": "1px"})
@@ -115,7 +113,6 @@ assert-css: (".sidebar .others h3", {"border-bottom-width": "0px"}, ALL)
 goto: file://|DOC_PATH|/test_docs/union.HeavilyDocumentedUnion.html
 
 assert-css: ("h1.fqn", {"font-size": "24px"})
-assert-css: (".main-heading", {"border-bottom-width": "1px"})
 
 assert-css: ("h2#top-doc-prose-title", {"font-size": "20.8px"})
 assert-css: ("h2#top-doc-prose-title", {"border-bottom-width": "1px"})
@@ -148,7 +145,6 @@ assert-css: ("h6#sub-heading-for-union-impl-item-doc", {"border-bottom-width": "
 goto: file://|DOC_PATH|/test_docs/macro.heavily_documented_macro.html
 
 assert-css: ("h1.fqn", {"font-size": "24px"})
-assert-css: (".main-heading", {"border-bottom-width": "1px"})
 
 assert-css: ("h2#top-doc-prose-title", {"font-size": "20.8px"})
 assert-css: ("h2#top-doc-prose-title", {"border-bottom-width": "1px"})
diff --git a/src/test/rustdoc-gui/toggle-docs-mobile.goml b/src/test/rustdoc-gui/toggle-docs-mobile.goml
index 67b9164cfec..4c83fd6c0e3 100644
--- a/src/test/rustdoc-gui/toggle-docs-mobile.goml
+++ b/src/test/rustdoc-gui/toggle-docs-mobile.goml
@@ -1,12 +1,12 @@
 goto: file://|DOC_PATH|/test_docs/struct.Foo.html
 size: (433, 600)
 assert-attribute: (".top-doc", {"open": ""})
-click: (4, 260) // This is the position of the top doc comment toggle
+click: (4, 250) // This is the position of the top doc comment toggle
 assert-attribute-false: (".top-doc", {"open": ""})
-click: (4, 260)
+click: (4, 250)
 assert-attribute: (".top-doc", {"open": ""})
 // To ensure that the toggle isn't over the text, we check that the toggle isn't clicked.
-click: (3, 260)
+click: (3, 250)
 assert-attribute: (".top-doc", {"open": ""})
 
 // Assert the position of the toggle on the top doc block.
@@ -22,10 +22,10 @@ assert-position: (
 // Now we do the same but with a little bigger width
 size: (600, 600)
 assert-attribute: (".top-doc", {"open": ""})
-click: (4, 260) // New Y position since all search elements are back on one line.
+click: (4, 250) // New Y position since all search elements are back on one line.
 assert-attribute-false: (".top-doc", {"open": ""})
-click: (4, 260)
+click: (4, 250)
 assert-attribute: (".top-doc", {"open": ""})
 // To ensure that the toggle isn't over the text, we check that the toggle isn't clicked.
-click: (3, 260)
+click: (3, 250)
 assert-attribute: (".top-doc", {"open": ""})
diff --git a/src/test/ui/derive-uninhabited-enum-38885.stderr b/src/test/ui/derive-uninhabited-enum-38885.stderr
index 72607629d3c..2a44e56a330 100644
--- a/src/test/ui/derive-uninhabited-enum-38885.stderr
+++ b/src/test/ui/derive-uninhabited-enum-38885.stderr
@@ -5,6 +5,12 @@ LL |     Void(Void),
    |     ^^^^^^^^^^
    |
    = note: `-W dead-code` implied by `-W unused`
+note: `Foo` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
+  --> $DIR/derive-uninhabited-enum-38885.rs:10:10
+   |
+LL | #[derive(Debug)]
+   |          ^^^^^
+   = note: this warning originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 warning: 1 warning emitted
 
diff --git a/src/test/ui/derives/clone-debug-dead-code.stderr b/src/test/ui/derives/clone-debug-dead-code.stderr
index 226007f3647..67bb574315a 100644
--- a/src/test/ui/derives/clone-debug-dead-code.stderr
+++ b/src/test/ui/derives/clone-debug-dead-code.stderr
@@ -15,18 +15,39 @@ error: field is never read: `f`
    |
 LL | struct B { f: () }
    |            ^^^^^
+   |
+note: `B` has a derived impl for the trait `Clone`, but this is intentionally ignored during dead code analysis
+  --> $DIR/clone-debug-dead-code.rs:9:10
+   |
+LL | #[derive(Clone)]
+   |          ^^^^^
+   = note: this error originates in the derive macro `Clone` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: field is never read: `f`
   --> $DIR/clone-debug-dead-code.rs:14:12
    |
 LL | struct C { f: () }
    |            ^^^^^
+   |
+note: `C` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
+  --> $DIR/clone-debug-dead-code.rs:13:10
+   |
+LL | #[derive(Debug)]
+   |          ^^^^^
+   = note: this error originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: field is never read: `f`
   --> $DIR/clone-debug-dead-code.rs:18:12
    |
 LL | struct D { f: () }
    |            ^^^^^
+   |
+note: `D` has derived impls for the traits `Clone` and `Debug`, but these are intentionally ignored during dead code analysis
+  --> $DIR/clone-debug-dead-code.rs:17:10
+   |
+LL | #[derive(Debug,Clone)]
+   |          ^^^^^ ^^^^^
+   = note: this error originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: field is never read: `f`
   --> $DIR/clone-debug-dead-code.rs:21:12
diff --git a/src/test/ui/expr/if/attrs/let-chains-attr.rs b/src/test/ui/expr/if/attrs/let-chains-attr.rs
index 5237a9ff396..2cd8731141a 100644
--- a/src/test/ui/expr/if/attrs/let-chains-attr.rs
+++ b/src/test/ui/expr/if/attrs/let-chains-attr.rs
@@ -1,6 +1,6 @@
 // check-pass
 
-#![feature(let_chains)] //~ WARN the feature `let_chains` is incomplete
+#![feature(let_chains)]
 
 #[cfg(FALSE)]
 fn foo() {
diff --git a/src/test/ui/expr/if/attrs/let-chains-attr.stderr b/src/test/ui/expr/if/attrs/let-chains-attr.stderr
deleted file mode 100644
index 8b987471534..00000000000
--- a/src/test/ui/expr/if/attrs/let-chains-attr.stderr
+++ /dev/null
@@ -1,11 +0,0 @@
-warning: the feature `let_chains` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/let-chains-attr.rs:3:12
-   |
-LL | #![feature(let_chains)]
-   |            ^^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
-
-warning: 1 warning emitted
-
diff --git a/src/test/ui/lint/dead-code/unused-variant.stderr b/src/test/ui/lint/dead-code/unused-variant.stderr
index a547f5af4b0..3b5683a7748 100644
--- a/src/test/ui/lint/dead-code/unused-variant.stderr
+++ b/src/test/ui/lint/dead-code/unused-variant.stderr
@@ -9,6 +9,12 @@ note: the lint level is defined here
    |
 LL | #![deny(dead_code)]
    |         ^^^^^^^^^
+note: `Enum` has a derived impl for the trait `Clone`, but this is intentionally ignored during dead code analysis
+  --> $DIR/unused-variant.rs:3:10
+   |
+LL | #[derive(Clone)]
+   |          ^^^^^
+   = note: this error originates in the derive macro `Clone` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/mir/mir_let_chains_drop_order.rs b/src/test/ui/mir/mir_let_chains_drop_order.rs
new file mode 100644
index 00000000000..01f943c87dd
--- /dev/null
+++ b/src/test/ui/mir/mir_let_chains_drop_order.rs
@@ -0,0 +1,93 @@
+// run-pass
+// needs-unwind
+// ignore-wasm32-bare compiled with panic=abort by default
+
+// See `mir_drop_order.rs` for more information
+
+#![feature(let_chains)]
+
+use std::cell::RefCell;
+use std::panic;
+
+pub struct DropLogger<'a, T> {
+    extra: T,
+    id: usize,
+    log: &'a panic::AssertUnwindSafe<RefCell<Vec<usize>>>
+}
+
+impl<'a, T> Drop for DropLogger<'a, T> {
+    fn drop(&mut self) {
+        self.log.0.borrow_mut().push(self.id);
+    }
+}
+
+struct InjectedFailure;
+
+#[allow(unreachable_code)]
+fn main() {
+    let log = panic::AssertUnwindSafe(RefCell::new(vec![]));
+    let d = |id, extra| DropLogger { extra, id: id, log: &log };
+    let get = || -> Vec<_> {
+        let mut m = log.0.borrow_mut();
+        let n = m.drain(..);
+        n.collect()
+    };
+
+    {
+        let _x = (
+            d(
+                0,
+                d(
+                    1,
+                    if let Some(_) = d(2, Some(true)).extra && let DropLogger { .. } = d(3, None) {
+                        None
+                    } else {
+                        Some(true)
+                    }
+                ).extra
+            ),
+            d(4, None),
+            &d(5, None),
+            d(6, None),
+            if let DropLogger { .. } = d(7, None) && let DropLogger { .. } = d(8, None) {
+                d(9, None)
+            }
+            else {
+                // 10 is not constructed
+                d(10, None)
+            }
+        );
+        assert_eq!(get(), vec![3, 8, 7, 1, 2]);
+    }
+    assert_eq!(get(), vec![0, 4, 6, 9, 5]);
+
+    let _ = std::panic::catch_unwind(|| {
+        (
+            d(
+                11,
+                d(
+                    12,
+                    if let Some(_) = d(13, Some(true)).extra
+                        && let DropLogger { .. } = d(14, None)
+                    {
+                        None
+                    } else {
+                        Some(true)
+                    }
+                ).extra
+            ),
+            d(15, None),
+            &d(16, None),
+            d(17, None),
+            if let DropLogger { .. } = d(18, None) && let DropLogger { .. } = d(19, None) {
+                d(20, None)
+            }
+            else {
+                // 10 is not constructed
+                d(21, None)
+            },
+            panic::panic_any(InjectedFailure)
+        );
+    });
+    assert_eq!(get(), vec![14, 19, 20, 17, 15, 11, 18, 16, 12, 13]);
+}
diff --git a/src/test/ui/pattern/issue-82290.rs b/src/test/ui/pattern/issue-82290.rs
deleted file mode 100644
index d8da0ac8aa6..00000000000
--- a/src/test/ui/pattern/issue-82290.rs
+++ /dev/null
@@ -1,9 +0,0 @@
-// check-pass
-
-#![feature(let_chains)] //~ WARN the feature `let_chains` is incomplete
-
-fn main() {
-    if true && let x = 1 { //~ WARN irrefutable `let` pattern
-        let _ = x;
-    }
-}
diff --git a/src/test/ui/pattern/issue-82290.stderr b/src/test/ui/pattern/issue-82290.stderr
deleted file mode 100644
index 0a3cf2c794f..00000000000
--- a/src/test/ui/pattern/issue-82290.stderr
+++ /dev/null
@@ -1,21 +0,0 @@
-warning: the feature `let_chains` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/issue-82290.rs:3:12
-   |
-LL | #![feature(let_chains)]
-   |            ^^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
-
-warning: irrefutable `let` pattern
-  --> $DIR/issue-82290.rs:6:16
-   |
-LL |     if true && let x = 1 {
-   |                ^^^^^^^^^
-   |
-   = note: `#[warn(irrefutable_let_patterns)]` on by default
-   = note: this pattern will always match, so the `let` is useless
-   = help: consider removing `let`
-
-warning: 2 warnings emitted
-
diff --git a/src/test/ui/rfc-2294-if-let-guard/feature-gate.rs b/src/test/ui/rfc-2294-if-let-guard/feature-gate.rs
index 2a2c0be5263..34d2d84da93 100644
--- a/src/test/ui/rfc-2294-if-let-guard/feature-gate.rs
+++ b/src/test/ui/rfc-2294-if-let-guard/feature-gate.rs
@@ -8,36 +8,36 @@ fn _if_let_guard() {
         //~^ ERROR `if let` guards are experimental
 
         () if (let 0 = 1) => {}
-        //~^ ERROR `let` expressions in this position are experimental
+        //~^ ERROR `let` expressions in this position are unstable
 
         () if (((let 0 = 1))) => {}
-        //~^ ERROR `let` expressions in this position are experimental
+        //~^ ERROR `let` expressions in this position are unstable
 
         () if true && let 0 = 1 => {}
-        //~^ ERROR `let` expressions in this position are experimental
+        //~^ ERROR `let` expressions in this position are unstable
 
         () if let 0 = 1 && true => {}
-        //~^ ERROR `let` expressions in this position are experimental
+        //~^ ERROR `let` expressions in this position are unstable
 
         () if (let 0 = 1) && true => {}
-        //~^ ERROR `let` expressions in this position are experimental
+        //~^ ERROR `let` expressions in this position are unstable
 
         () if true && (let 0 = 1) => {}
-        //~^ ERROR `let` expressions in this position are experimental
+        //~^ ERROR `let` expressions in this position are unstable
 
         () if (let 0 = 1) && (let 0 = 1) => {}
-        //~^ ERROR `let` expressions in this position are experimental
-        //~| ERROR `let` expressions in this position are experimental
+        //~^ ERROR `let` expressions in this position are unstable
+        //~| ERROR `let` expressions in this position are unstable
 
         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
-        //~^ ERROR `let` expressions in this position are experimental
-        //~| ERROR `let` expressions in this position are experimental
-        //~| ERROR `let` expressions in this position are experimental
-        //~| ERROR `let` expressions in this position are experimental
-        //~| ERROR `let` expressions in this position are experimental
+        //~^ ERROR `let` expressions in this position are unstable
+        //~| ERROR `let` expressions in this position are unstable
+        //~| ERROR `let` expressions in this position are unstable
+        //~| ERROR `let` expressions in this position are unstable
+        //~| ERROR `let` expressions in this position are unstable
 
         () if let Range { start: _, end: _ } = (true..true) && false => {}
-        //~^ ERROR `let` expressions in this position are experimental
+        //~^ ERROR `let` expressions in this position are unstable
         _ => {}
     }
 }
@@ -52,9 +52,9 @@ fn _macros() {
         }
     }
     use_expr!((let 0 = 1 && 0 == 0));
-    //~^ ERROR `let` expressions in this position are experimental
+    //~^ ERROR `let` expressions in this position are unstable
     use_expr!((let 0 = 1));
-    //~^ ERROR `let` expressions in this position are experimental
+    //~^ ERROR `let` expressions in this position are unstable
     match () {
         #[cfg(FALSE)]
         () if let 0 = 1 => {}
diff --git a/src/test/ui/rfc-2294-if-let-guard/feature-gate.stderr b/src/test/ui/rfc-2294-if-let-guard/feature-gate.stderr
index bedcdcb019b..0cda6ba9a99 100644
--- a/src/test/ui/rfc-2294-if-let-guard/feature-gate.stderr
+++ b/src/test/ui/rfc-2294-if-let-guard/feature-gate.stderr
@@ -27,7 +27,7 @@ LL |         () if let 0 = 1 => {}
    = help: add `#![feature(if_let_guard)]` to the crate attributes to enable
    = help: you can write `if matches!(<expr>, <pattern>)` instead of `if let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:10:16
    |
 LL |         () if (let 0 = 1) => {}
@@ -35,9 +35,8 @@ LL |         () if (let 0 = 1) => {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:13:18
    |
 LL |         () if (((let 0 = 1))) => {}
@@ -45,9 +44,8 @@ LL |         () if (((let 0 = 1))) => {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:16:23
    |
 LL |         () if true && let 0 = 1 => {}
@@ -55,9 +53,8 @@ LL |         () if true && let 0 = 1 => {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:19:15
    |
 LL |         () if let 0 = 1 && true => {}
@@ -65,9 +62,8 @@ LL |         () if let 0 = 1 && true => {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:22:16
    |
 LL |         () if (let 0 = 1) && true => {}
@@ -75,9 +71,8 @@ LL |         () if (let 0 = 1) && true => {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:25:24
    |
 LL |         () if true && (let 0 = 1) => {}
@@ -85,9 +80,8 @@ LL |         () if true && (let 0 = 1) => {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:28:16
    |
 LL |         () if (let 0 = 1) && (let 0 = 1) => {}
@@ -95,9 +89,8 @@ LL |         () if (let 0 = 1) && (let 0 = 1) => {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:28:31
    |
 LL |         () if (let 0 = 1) && (let 0 = 1) => {}
@@ -105,9 +98,8 @@ LL |         () if (let 0 = 1) && (let 0 = 1) => {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:32:15
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
@@ -115,9 +107,8 @@ LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 =
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:32:28
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
@@ -125,9 +116,8 @@ LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 =
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:32:42
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
@@ -135,9 +125,8 @@ LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 =
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:32:55
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
@@ -145,9 +134,8 @@ LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 =
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:32:68
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
@@ -155,9 +143,8 @@ LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 =
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:39:15
    |
 LL |         () if let Range { start: _, end: _ } = (true..true) && false => {}
@@ -165,9 +152,8 @@ LL |         () if let Range { start: _, end: _ } = (true..true) && false => {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:54:16
    |
 LL |     use_expr!((let 0 = 1 && 0 == 0));
@@ -175,9 +161,8 @@ LL |     use_expr!((let 0 = 1 && 0 == 0));
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:56:16
    |
 LL |     use_expr!((let 0 = 1));
@@ -185,7 +170,6 @@ LL |     use_expr!((let 0 = 1));
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
 error: aborting due to 19 previous errors
 
diff --git a/src/test/ui/rfc-2497-if-let-chains/ast-lowering-does-not-wrap-let-chains.rs b/src/test/ui/rfc-2497-if-let-chains/ast-lowering-does-not-wrap-let-chains.rs
new file mode 100644
index 00000000000..708bcdd0aef
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/ast-lowering-does-not-wrap-let-chains.rs
@@ -0,0 +1,15 @@
+// run-pass
+
+#![feature(let_chains)]
+
+fn main() {
+    let first = Some(1);
+    let second = Some(2);
+    let mut n = 0;
+    if let x = first && let y = second && 1 == 1 {
+        assert_eq!(x, first);
+        assert_eq!(y, second);
+        n = 1;
+    }
+    assert_eq!(n, 1);
+}
diff --git a/src/test/ui/rfc-2497-if-let-chains/ast-pretty-check.rs b/src/test/ui/rfc-2497-if-let-chains/ast-pretty-check.rs
index 710fdd57ed7..69bc189dd35 100644
--- a/src/test/ui/rfc-2497-if-let-chains/ast-pretty-check.rs
+++ b/src/test/ui/rfc-2497-if-let-chains/ast-pretty-check.rs
@@ -1,4 +1,4 @@
-// build-pass (FIXME(62277): could be check-pass?)
+// check-pass
 // compile-flags: -Z unpretty=expanded
 
 fn main() {
diff --git a/src/test/ui/rfc-2497-if-let-chains/ast-pretty-check.stdout b/src/test/ui/rfc-2497-if-let-chains/ast-pretty-check.stdout
index 6052ea95d0f..e737ef26e9b 100644
--- a/src/test/ui/rfc-2497-if-let-chains/ast-pretty-check.stdout
+++ b/src/test/ui/rfc-2497-if-let-chains/ast-pretty-check.stdout
@@ -4,7 +4,7 @@
 use ::std::prelude::rust_2015::*;
 #[macro_use]
 extern crate std;
-// build-pass (FIXME(62277): could be check-pass?)
+// check-pass
 // compile-flags: -Z unpretty=expanded
 
 fn main() { if let 0 = 1 {} }
diff --git a/src/test/ui/rfc-2497-if-let-chains/chains-without-let.rs b/src/test/ui/rfc-2497-if-let-chains/chains-without-let.rs
new file mode 100644
index 00000000000..a7e108d72d1
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/chains-without-let.rs
@@ -0,0 +1,20 @@
+fn and_chain() {
+    let z;
+    if true && { z = 3; true} && z == 3 {}
+    //~^ ERROR use of possibly-uninitialized
+}
+
+fn and_chain_2() {
+    let z;
+    true && { z = 3; true} && z == 3;
+    //~^ ERROR use of possibly-uninitialized
+}
+
+fn or_chain() {
+    let z;
+    if false || { z = 3; false} || z == 3 {}
+    //~^ ERROR use of possibly-uninitialized
+}
+
+fn main() {
+}
diff --git a/src/test/ui/rfc-2497-if-let-chains/chains-without-let.stderr b/src/test/ui/rfc-2497-if-let-chains/chains-without-let.stderr
new file mode 100644
index 00000000000..3c47040cc8c
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/chains-without-let.stderr
@@ -0,0 +1,21 @@
+error[E0381]: use of possibly-uninitialized variable: `z`
+  --> $DIR/chains-without-let.rs:3:34
+   |
+LL |     if true && { z = 3; true} && z == 3 {}
+   |                                  ^ use of possibly-uninitialized `z`
+
+error[E0381]: use of possibly-uninitialized variable: `z`
+  --> $DIR/chains-without-let.rs:9:31
+   |
+LL |     true && { z = 3; true} && z == 3;
+   |                               ^ use of possibly-uninitialized `z`
+
+error[E0381]: use of possibly-uninitialized variable: `z`
+  --> $DIR/chains-without-let.rs:15:36
+   |
+LL |     if false || { z = 3; false} || z == 3 {}
+   |                                    ^ use of possibly-uninitialized `z`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0381`.
diff --git a/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.rs b/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.rs
index b0b3464c610..5b2693d07a7 100644
--- a/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.rs
+++ b/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.rs
@@ -18,7 +18,6 @@
 // To that end, we check some positions which is not part of the language above.
 
 #![feature(let_chains)] // Avoid inflating `.stderr` with overzealous gates in this test.
-//~^ WARN the feature `let_chains` is incomplete
 
 #![allow(irrefutable_let_patterns)]
 
diff --git a/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.stderr b/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.stderr
index 1433a16d727..4c830554d43 100644
--- a/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.stderr
+++ b/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.stderr
@@ -1,5 +1,5 @@
 error: expressions must be enclosed in braces to be used as const generic arguments
-  --> $DIR/disallowed-positions.rs:233:9
+  --> $DIR/disallowed-positions.rs:232:9
    |
 LL |         true && let 1 = 1
    |         ^^^^^^^^^^^^^^^^^
@@ -10,7 +10,7 @@ LL |         { true && let 1 = 1 }
    |         +                   +
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:30:9
+  --> $DIR/disallowed-positions.rs:29:9
    |
 LL |     if &let 0 = 0 {}
    |         ^^^^^^^^^
@@ -19,7 +19,7 @@ LL |     if &let 0 = 0 {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:33:9
+  --> $DIR/disallowed-positions.rs:32:9
    |
 LL |     if !let 0 = 0 {}
    |         ^^^^^^^^^
@@ -28,7 +28,7 @@ LL |     if !let 0 = 0 {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:34:9
+  --> $DIR/disallowed-positions.rs:33:9
    |
 LL |     if *let 0 = 0 {}
    |         ^^^^^^^^^
@@ -37,7 +37,7 @@ LL |     if *let 0 = 0 {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:36:9
+  --> $DIR/disallowed-positions.rs:35:9
    |
 LL |     if -let 0 = 0 {}
    |         ^^^^^^^^^
@@ -46,7 +46,7 @@ LL |     if -let 0 = 0 {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:44:9
+  --> $DIR/disallowed-positions.rs:43:9
    |
 LL |     if (let 0 = 0)? {}
    |         ^^^^^^^^^
@@ -55,7 +55,7 @@ LL |     if (let 0 = 0)? {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:48:16
+  --> $DIR/disallowed-positions.rs:47:16
    |
 LL |     if true || let 0 = 0 {}
    |                ^^^^^^^^^
@@ -64,7 +64,7 @@ LL |     if true || let 0 = 0 {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:49:17
+  --> $DIR/disallowed-positions.rs:48:17
    |
 LL |     if (true || let 0 = 0) {}
    |                 ^^^^^^^^^
@@ -73,7 +73,7 @@ LL |     if (true || let 0 = 0) {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:50:25
+  --> $DIR/disallowed-positions.rs:49:25
    |
 LL |     if true && (true || let 0 = 0) {}
    |                         ^^^^^^^^^
@@ -82,7 +82,7 @@ LL |     if true && (true || let 0 = 0) {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:51:25
+  --> $DIR/disallowed-positions.rs:50:25
    |
 LL |     if true || (true && let 0 = 0) {}
    |                         ^^^^^^^^^
@@ -91,7 +91,7 @@ LL |     if true || (true && let 0 = 0) {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:54:12
+  --> $DIR/disallowed-positions.rs:53:12
    |
 LL |     if x = let 0 = 0 {}
    |            ^^^^^^^^^
@@ -100,7 +100,7 @@ LL |     if x = let 0 = 0 {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:57:15
+  --> $DIR/disallowed-positions.rs:56:15
    |
 LL |     if true..(let 0 = 0) {}
    |               ^^^^^^^^^
@@ -109,7 +109,7 @@ LL |     if true..(let 0 = 0) {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:59:11
+  --> $DIR/disallowed-positions.rs:58:11
    |
 LL |     if ..(let 0 = 0) {}
    |           ^^^^^^^^^
@@ -118,7 +118,7 @@ LL |     if ..(let 0 = 0) {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:61:9
+  --> $DIR/disallowed-positions.rs:60:9
    |
 LL |     if (let 0 = 0).. {}
    |         ^^^^^^^^^
@@ -127,7 +127,7 @@ LL |     if (let 0 = 0).. {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:65:8
+  --> $DIR/disallowed-positions.rs:64:8
    |
 LL |     if let Range { start: _, end: _ } = true..true && false {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -136,7 +136,7 @@ LL |     if let Range { start: _, end: _ } = true..true && false {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:69:8
+  --> $DIR/disallowed-positions.rs:68:8
    |
 LL |     if let Range { start: _, end: _ } = true..true || false {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -145,7 +145,7 @@ LL |     if let Range { start: _, end: _ } = true..true || false {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:76:8
+  --> $DIR/disallowed-positions.rs:75:8
    |
 LL |     if let Range { start: F, end } = F..|| true {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -154,7 +154,7 @@ LL |     if let Range { start: F, end } = F..|| true {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:84:8
+  --> $DIR/disallowed-positions.rs:83:8
    |
 LL |     if let Range { start: true, end } = t..&&false {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -163,7 +163,7 @@ LL |     if let Range { start: true, end } = t..&&false {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:90:19
+  --> $DIR/disallowed-positions.rs:89:19
    |
 LL |     if let true = let true = true {}
    |                   ^^^^^^^^^^^^^^^
@@ -172,7 +172,7 @@ LL |     if let true = let true = true {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:94:12
+  --> $DIR/disallowed-positions.rs:93:12
    |
 LL |     while &let 0 = 0 {}
    |            ^^^^^^^^^
@@ -181,7 +181,7 @@ LL |     while &let 0 = 0 {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:97:12
+  --> $DIR/disallowed-positions.rs:96:12
    |
 LL |     while !let 0 = 0 {}
    |            ^^^^^^^^^
@@ -190,7 +190,7 @@ LL |     while !let 0 = 0 {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:98:12
+  --> $DIR/disallowed-positions.rs:97:12
    |
 LL |     while *let 0 = 0 {}
    |            ^^^^^^^^^
@@ -199,7 +199,7 @@ LL |     while *let 0 = 0 {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:100:12
+  --> $DIR/disallowed-positions.rs:99:12
    |
 LL |     while -let 0 = 0 {}
    |            ^^^^^^^^^
@@ -208,7 +208,7 @@ LL |     while -let 0 = 0 {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:108:12
+  --> $DIR/disallowed-positions.rs:107:12
    |
 LL |     while (let 0 = 0)? {}
    |            ^^^^^^^^^
@@ -217,7 +217,7 @@ LL |     while (let 0 = 0)? {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:112:19
+  --> $DIR/disallowed-positions.rs:111:19
    |
 LL |     while true || let 0 = 0 {}
    |                   ^^^^^^^^^
@@ -226,7 +226,7 @@ LL |     while true || let 0 = 0 {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:113:20
+  --> $DIR/disallowed-positions.rs:112:20
    |
 LL |     while (true || let 0 = 0) {}
    |                    ^^^^^^^^^
@@ -235,7 +235,7 @@ LL |     while (true || let 0 = 0) {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:114:28
+  --> $DIR/disallowed-positions.rs:113:28
    |
 LL |     while true && (true || let 0 = 0) {}
    |                            ^^^^^^^^^
@@ -244,7 +244,7 @@ LL |     while true && (true || let 0 = 0) {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:115:28
+  --> $DIR/disallowed-positions.rs:114:28
    |
 LL |     while true || (true && let 0 = 0) {}
    |                            ^^^^^^^^^
@@ -253,7 +253,7 @@ LL |     while true || (true && let 0 = 0) {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:118:15
+  --> $DIR/disallowed-positions.rs:117:15
    |
 LL |     while x = let 0 = 0 {}
    |               ^^^^^^^^^
@@ -262,7 +262,7 @@ LL |     while x = let 0 = 0 {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:121:18
+  --> $DIR/disallowed-positions.rs:120:18
    |
 LL |     while true..(let 0 = 0) {}
    |                  ^^^^^^^^^
@@ -271,7 +271,7 @@ LL |     while true..(let 0 = 0) {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:123:14
+  --> $DIR/disallowed-positions.rs:122:14
    |
 LL |     while ..(let 0 = 0) {}
    |              ^^^^^^^^^
@@ -280,7 +280,7 @@ LL |     while ..(let 0 = 0) {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:125:12
+  --> $DIR/disallowed-positions.rs:124:12
    |
 LL |     while (let 0 = 0).. {}
    |            ^^^^^^^^^
@@ -289,7 +289,7 @@ LL |     while (let 0 = 0).. {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:129:11
+  --> $DIR/disallowed-positions.rs:128:11
    |
 LL |     while let Range { start: _, end: _ } = true..true && false {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -298,7 +298,7 @@ LL |     while let Range { start: _, end: _ } = true..true && false {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:133:11
+  --> $DIR/disallowed-positions.rs:132:11
    |
 LL |     while let Range { start: _, end: _ } = true..true || false {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -307,7 +307,7 @@ LL |     while let Range { start: _, end: _ } = true..true || false {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:140:11
+  --> $DIR/disallowed-positions.rs:139:11
    |
 LL |     while let Range { start: F, end } = F..|| true {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -316,7 +316,7 @@ LL |     while let Range { start: F, end } = F..|| true {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:148:11
+  --> $DIR/disallowed-positions.rs:147:11
    |
 LL |     while let Range { start: true, end } = t..&&false {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -325,7 +325,7 @@ LL |     while let Range { start: true, end } = t..&&false {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:154:22
+  --> $DIR/disallowed-positions.rs:153:22
    |
 LL |     while let true = let true = true {}
    |                      ^^^^^^^^^^^^^^^
@@ -334,7 +334,7 @@ LL |     while let true = let true = true {}
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:168:6
+  --> $DIR/disallowed-positions.rs:167:6
    |
 LL |     &let 0 = 0;
    |      ^^^^^^^^^
@@ -343,7 +343,7 @@ LL |     &let 0 = 0;
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:170:6
+  --> $DIR/disallowed-positions.rs:169:6
    |
 LL |     !let 0 = 0;
    |      ^^^^^^^^^
@@ -352,7 +352,7 @@ LL |     !let 0 = 0;
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:171:6
+  --> $DIR/disallowed-positions.rs:170:6
    |
 LL |     *let 0 = 0;
    |      ^^^^^^^^^
@@ -361,7 +361,7 @@ LL |     *let 0 = 0;
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:173:6
+  --> $DIR/disallowed-positions.rs:172:6
    |
 LL |     -let 0 = 0;
    |      ^^^^^^^^^
@@ -370,7 +370,7 @@ LL |     -let 0 = 0;
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:181:6
+  --> $DIR/disallowed-positions.rs:180:6
    |
 LL |     (let 0 = 0)?;
    |      ^^^^^^^^^
@@ -379,7 +379,7 @@ LL |     (let 0 = 0)?;
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:185:13
+  --> $DIR/disallowed-positions.rs:184:13
    |
 LL |     true || let 0 = 0;
    |             ^^^^^^^^^
@@ -388,7 +388,7 @@ LL |     true || let 0 = 0;
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:186:14
+  --> $DIR/disallowed-positions.rs:185:14
    |
 LL |     (true || let 0 = 0);
    |              ^^^^^^^^^
@@ -397,7 +397,7 @@ LL |     (true || let 0 = 0);
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:187:22
+  --> $DIR/disallowed-positions.rs:186:22
    |
 LL |     true && (true || let 0 = 0);
    |                      ^^^^^^^^^
@@ -406,7 +406,7 @@ LL |     true && (true || let 0 = 0);
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:190:9
+  --> $DIR/disallowed-positions.rs:189:9
    |
 LL |     x = let 0 = 0;
    |         ^^^^^^^^^
@@ -415,7 +415,7 @@ LL |     x = let 0 = 0;
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:192:12
+  --> $DIR/disallowed-positions.rs:191:12
    |
 LL |     true..(let 0 = 0);
    |            ^^^^^^^^^
@@ -424,7 +424,7 @@ LL |     true..(let 0 = 0);
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:193:8
+  --> $DIR/disallowed-positions.rs:192:8
    |
 LL |     ..(let 0 = 0);
    |        ^^^^^^^^^
@@ -433,7 +433,7 @@ LL |     ..(let 0 = 0);
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:194:6
+  --> $DIR/disallowed-positions.rs:193:6
    |
 LL |     (let 0 = 0)..;
    |      ^^^^^^^^^
@@ -442,7 +442,7 @@ LL |     (let 0 = 0)..;
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:196:6
+  --> $DIR/disallowed-positions.rs:195:6
    |
 LL |     (let Range { start: _, end: _ } = true..true || false);
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -451,7 +451,7 @@ LL |     (let Range { start: _, end: _ } = true..true || false);
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:200:6
+  --> $DIR/disallowed-positions.rs:199:6
    |
 LL |     (let true = let true = true);
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -460,7 +460,7 @@ LL |     (let true = let true = true);
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:204:6
+  --> $DIR/disallowed-positions.rs:203:6
    |
 LL |     &let 0 = 0
    |      ^^^^^^^^^
@@ -469,7 +469,7 @@ LL |     &let 0 = 0
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:215:17
+  --> $DIR/disallowed-positions.rs:214:17
    |
 LL |         true && let 1 = 1
    |                 ^^^^^^^^^
@@ -478,7 +478,7 @@ LL |         true && let 1 = 1
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:219:17
+  --> $DIR/disallowed-positions.rs:218:17
    |
 LL |         true && let 1 = 1
    |                 ^^^^^^^^^
@@ -487,7 +487,7 @@ LL |         true && let 1 = 1
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:223:17
+  --> $DIR/disallowed-positions.rs:222:17
    |
 LL |         true && let 1 = 1
    |                 ^^^^^^^^^
@@ -496,7 +496,7 @@ LL |         true && let 1 = 1
    = note: as well as when nested within `&&` and parentheses in those conditions
 
 error: `let` expressions are not supported here
-  --> $DIR/disallowed-positions.rs:233:17
+  --> $DIR/disallowed-positions.rs:232:17
    |
 LL |         true && let 1 = 1
    |                 ^^^^^^^^^
@@ -504,17 +504,8 @@ LL |         true && let 1 = 1
    = note: only supported directly in conditions of `if`- and `while`-expressions
    = note: as well as when nested within `&&` and parentheses in those conditions
 
-warning: the feature `let_chains` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/disallowed-positions.rs:20:12
-   |
-LL | #![feature(let_chains)] // Avoid inflating `.stderr` with overzealous gates in this test.
-   |            ^^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
-
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:30:8
+  --> $DIR/disallowed-positions.rs:29:8
    |
 LL |     if &let 0 = 0 {}
    |        ^^^^^^^^^^ expected `bool`, found `&bool`
@@ -526,19 +517,19 @@ LL +     if let 0 = 0 {}
    | 
 
 error[E0614]: type `bool` cannot be dereferenced
-  --> $DIR/disallowed-positions.rs:34:8
+  --> $DIR/disallowed-positions.rs:33:8
    |
 LL |     if *let 0 = 0 {}
    |        ^^^^^^^^^^
 
 error[E0600]: cannot apply unary operator `-` to type `bool`
-  --> $DIR/disallowed-positions.rs:36:8
+  --> $DIR/disallowed-positions.rs:35:8
    |
 LL |     if -let 0 = 0 {}
    |        ^^^^^^^^^^ cannot apply unary operator `-`
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/disallowed-positions.rs:44:8
+  --> $DIR/disallowed-positions.rs:43:8
    |
 LL |     if (let 0 = 0)? {}
    |        ^^^^^^^^^^^^ the `?` operator cannot be applied to type `bool`
@@ -546,7 +537,7 @@ LL |     if (let 0 = 0)? {}
    = help: the trait `Try` is not implemented for `bool`
 
 error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
-  --> $DIR/disallowed-positions.rs:44:19
+  --> $DIR/disallowed-positions.rs:43:19
    |
 LL | / fn nested_within_if_expr() {
 LL | |     if &let 0 = 0 {}
@@ -563,7 +554,7 @@ LL | | }
    = help: the trait `FromResidual<_>` is not implemented for `()`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:54:8
+  --> $DIR/disallowed-positions.rs:53:8
    |
 LL |     if x = let 0 = 0 {}
    |        ^^^^^^^^^^^^^ expected `bool`, found `()`
@@ -574,7 +565,7 @@ LL |     if x == let 0 = 0 {}
    |          ~~
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:57:8
+  --> $DIR/disallowed-positions.rs:56:8
    |
 LL |     if true..(let 0 = 0) {}
    |        ^^^^^^^^^^^^^^^^^ expected `bool`, found struct `std::ops::Range`
@@ -583,7 +574,7 @@ LL |     if true..(let 0 = 0) {}
             found struct `std::ops::Range<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:59:8
+  --> $DIR/disallowed-positions.rs:58:8
    |
 LL |     if ..(let 0 = 0) {}
    |        ^^^^^^^^^^^^^ expected `bool`, found struct `RangeTo`
@@ -592,7 +583,7 @@ LL |     if ..(let 0 = 0) {}
             found struct `RangeTo<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:61:8
+  --> $DIR/disallowed-positions.rs:60:8
    |
 LL |     if (let 0 = 0).. {}
    |        ^^^^^^^^^^^^^ expected `bool`, found struct `RangeFrom`
@@ -601,7 +592,7 @@ LL |     if (let 0 = 0).. {}
             found struct `RangeFrom<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:65:12
+  --> $DIR/disallowed-positions.rs:64:12
    |
 LL |     if let Range { start: _, end: _ } = true..true && false {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -612,7 +603,7 @@ LL |     if let Range { start: _, end: _ } = true..true && false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:65:8
+  --> $DIR/disallowed-positions.rs:64:8
    |
 LL |     if let Range { start: _, end: _ } = true..true && false {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found struct `std::ops::Range`
@@ -621,7 +612,7 @@ LL |     if let Range { start: _, end: _ } = true..true && false {}
             found struct `std::ops::Range<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:69:12
+  --> $DIR/disallowed-positions.rs:68:12
    |
 LL |     if let Range { start: _, end: _ } = true..true || false {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -632,7 +623,7 @@ LL |     if let Range { start: _, end: _ } = true..true || false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:69:8
+  --> $DIR/disallowed-positions.rs:68:8
    |
 LL |     if let Range { start: _, end: _ } = true..true || false {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found struct `std::ops::Range`
@@ -641,7 +632,7 @@ LL |     if let Range { start: _, end: _ } = true..true || false {}
             found struct `std::ops::Range<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:76:12
+  --> $DIR/disallowed-positions.rs:75:12
    |
 LL |     if let Range { start: F, end } = F..|| true {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `fn() -> bool`
@@ -652,16 +643,16 @@ LL |     if let Range { start: F, end } = F..|| true {}
                   found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:76:41
+  --> $DIR/disallowed-positions.rs:75:41
    |
 LL |     if let Range { start: F, end } = F..|| true {}
    |                                         ^^^^^^^ expected `bool`, found closure
    |
    = note: expected type `bool`
-           found closure `[closure@$DIR/disallowed-positions.rs:76:41: 76:48]`
+           found closure `[closure@$DIR/disallowed-positions.rs:75:41: 75:48]`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:76:8
+  --> $DIR/disallowed-positions.rs:75:8
    |
 LL |     if let Range { start: F, end } = F..|| true {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found struct `std::ops::Range`
@@ -670,7 +661,7 @@ LL |     if let Range { start: F, end } = F..|| true {}
             found struct `std::ops::Range<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:84:12
+  --> $DIR/disallowed-positions.rs:83:12
    |
 LL |     if let Range { start: true, end } = t..&&false {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `&&bool`
@@ -681,13 +672,13 @@ LL |     if let Range { start: true, end } = t..&&false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:84:44
+  --> $DIR/disallowed-positions.rs:83:44
    |
 LL |     if let Range { start: true, end } = t..&&false {}
    |                                            ^^^^^^^ expected `bool`, found `&&bool`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:84:8
+  --> $DIR/disallowed-positions.rs:83:8
    |
 LL |     if let Range { start: true, end } = t..&&false {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found struct `std::ops::Range`
@@ -696,7 +687,7 @@ LL |     if let Range { start: true, end } = t..&&false {}
             found struct `std::ops::Range<bool>`
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/disallowed-positions.rs:40:20
+  --> $DIR/disallowed-positions.rs:39:20
    |
 LL |         if let 0 = 0? {}
    |                    ^^ the `?` operator cannot be applied to type `{integer}`
@@ -704,7 +695,7 @@ LL |         if let 0 = 0? {}
    = help: the trait `Try` is not implemented for `{integer}`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:94:11
+  --> $DIR/disallowed-positions.rs:93:11
    |
 LL |     while &let 0 = 0 {}
    |           ^^^^^^^^^^ expected `bool`, found `&bool`
@@ -716,19 +707,19 @@ LL +     while let 0 = 0 {}
    | 
 
 error[E0614]: type `bool` cannot be dereferenced
-  --> $DIR/disallowed-positions.rs:98:11
+  --> $DIR/disallowed-positions.rs:97:11
    |
 LL |     while *let 0 = 0 {}
    |           ^^^^^^^^^^
 
 error[E0600]: cannot apply unary operator `-` to type `bool`
-  --> $DIR/disallowed-positions.rs:100:11
+  --> $DIR/disallowed-positions.rs:99:11
    |
 LL |     while -let 0 = 0 {}
    |           ^^^^^^^^^^ cannot apply unary operator `-`
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/disallowed-positions.rs:108:11
+  --> $DIR/disallowed-positions.rs:107:11
    |
 LL |     while (let 0 = 0)? {}
    |           ^^^^^^^^^^^^ the `?` operator cannot be applied to type `bool`
@@ -736,7 +727,7 @@ LL |     while (let 0 = 0)? {}
    = help: the trait `Try` is not implemented for `bool`
 
 error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
-  --> $DIR/disallowed-positions.rs:108:22
+  --> $DIR/disallowed-positions.rs:107:22
    |
 LL | / fn nested_within_while_expr() {
 LL | |     while &let 0 = 0 {}
@@ -753,7 +744,7 @@ LL | | }
    = help: the trait `FromResidual<_>` is not implemented for `()`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:118:11
+  --> $DIR/disallowed-positions.rs:117:11
    |
 LL |     while x = let 0 = 0 {}
    |           ^^^^^^^^^^^^^ expected `bool`, found `()`
@@ -764,7 +755,7 @@ LL |     while x == let 0 = 0 {}
    |             ~~
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:121:11
+  --> $DIR/disallowed-positions.rs:120:11
    |
 LL |     while true..(let 0 = 0) {}
    |           ^^^^^^^^^^^^^^^^^ expected `bool`, found struct `std::ops::Range`
@@ -773,7 +764,7 @@ LL |     while true..(let 0 = 0) {}
             found struct `std::ops::Range<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:123:11
+  --> $DIR/disallowed-positions.rs:122:11
    |
 LL |     while ..(let 0 = 0) {}
    |           ^^^^^^^^^^^^^ expected `bool`, found struct `RangeTo`
@@ -782,7 +773,7 @@ LL |     while ..(let 0 = 0) {}
             found struct `RangeTo<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:125:11
+  --> $DIR/disallowed-positions.rs:124:11
    |
 LL |     while (let 0 = 0).. {}
    |           ^^^^^^^^^^^^^ expected `bool`, found struct `RangeFrom`
@@ -791,7 +782,7 @@ LL |     while (let 0 = 0).. {}
             found struct `RangeFrom<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:129:15
+  --> $DIR/disallowed-positions.rs:128:15
    |
 LL |     while let Range { start: _, end: _ } = true..true && false {}
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -802,7 +793,7 @@ LL |     while let Range { start: _, end: _ } = true..true && false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:129:11
+  --> $DIR/disallowed-positions.rs:128:11
    |
 LL |     while let Range { start: _, end: _ } = true..true && false {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found struct `std::ops::Range`
@@ -811,7 +802,7 @@ LL |     while let Range { start: _, end: _ } = true..true && false {}
             found struct `std::ops::Range<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:133:15
+  --> $DIR/disallowed-positions.rs:132:15
    |
 LL |     while let Range { start: _, end: _ } = true..true || false {}
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -822,7 +813,7 @@ LL |     while let Range { start: _, end: _ } = true..true || false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:133:11
+  --> $DIR/disallowed-positions.rs:132:11
    |
 LL |     while let Range { start: _, end: _ } = true..true || false {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found struct `std::ops::Range`
@@ -831,7 +822,7 @@ LL |     while let Range { start: _, end: _ } = true..true || false {}
             found struct `std::ops::Range<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:140:15
+  --> $DIR/disallowed-positions.rs:139:15
    |
 LL |     while let Range { start: F, end } = F..|| true {}
    |               ^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `fn() -> bool`
@@ -842,16 +833,16 @@ LL |     while let Range { start: F, end } = F..|| true {}
                   found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:140:44
+  --> $DIR/disallowed-positions.rs:139:44
    |
 LL |     while let Range { start: F, end } = F..|| true {}
    |                                            ^^^^^^^ expected `bool`, found closure
    |
    = note: expected type `bool`
-           found closure `[closure@$DIR/disallowed-positions.rs:140:44: 140:51]`
+           found closure `[closure@$DIR/disallowed-positions.rs:139:44: 139:51]`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:140:11
+  --> $DIR/disallowed-positions.rs:139:11
    |
 LL |     while let Range { start: F, end } = F..|| true {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found struct `std::ops::Range`
@@ -860,7 +851,7 @@ LL |     while let Range { start: F, end } = F..|| true {}
             found struct `std::ops::Range<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:148:15
+  --> $DIR/disallowed-positions.rs:147:15
    |
 LL |     while let Range { start: true, end } = t..&&false {}
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `&&bool`
@@ -871,13 +862,13 @@ LL |     while let Range { start: true, end } = t..&&false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:148:47
+  --> $DIR/disallowed-positions.rs:147:47
    |
 LL |     while let Range { start: true, end } = t..&&false {}
    |                                               ^^^^^^^ expected `bool`, found `&&bool`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:148:11
+  --> $DIR/disallowed-positions.rs:147:11
    |
 LL |     while let Range { start: true, end } = t..&&false {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found struct `std::ops::Range`
@@ -886,7 +877,7 @@ LL |     while let Range { start: true, end } = t..&&false {}
             found struct `std::ops::Range<bool>`
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/disallowed-positions.rs:104:23
+  --> $DIR/disallowed-positions.rs:103:23
    |
 LL |         while let 0 = 0? {}
    |                       ^^ the `?` operator cannot be applied to type `{integer}`
@@ -894,19 +885,19 @@ LL |         while let 0 = 0? {}
    = help: the trait `Try` is not implemented for `{integer}`
 
 error[E0614]: type `bool` cannot be dereferenced
-  --> $DIR/disallowed-positions.rs:171:5
+  --> $DIR/disallowed-positions.rs:170:5
    |
 LL |     *let 0 = 0;
    |     ^^^^^^^^^^
 
 error[E0600]: cannot apply unary operator `-` to type `bool`
-  --> $DIR/disallowed-positions.rs:173:5
+  --> $DIR/disallowed-positions.rs:172:5
    |
 LL |     -let 0 = 0;
    |     ^^^^^^^^^^ cannot apply unary operator `-`
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/disallowed-positions.rs:181:5
+  --> $DIR/disallowed-positions.rs:180:5
    |
 LL |     (let 0 = 0)?;
    |     ^^^^^^^^^^^^ the `?` operator cannot be applied to type `bool`
@@ -914,7 +905,7 @@ LL |     (let 0 = 0)?;
    = help: the trait `Try` is not implemented for `bool`
 
 error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
-  --> $DIR/disallowed-positions.rs:181:16
+  --> $DIR/disallowed-positions.rs:180:16
    |
 LL | / fn outside_if_and_while_expr() {
 LL | |     &let 0 = 0;
@@ -931,7 +922,7 @@ LL | | }
    = help: the trait `FromResidual<_>` is not implemented for `()`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:196:10
+  --> $DIR/disallowed-positions.rs:195:10
    |
 LL |     (let Range { start: _, end: _ } = true..true || false);
    |          ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -942,7 +933,7 @@ LL |     (let Range { start: _, end: _ } = true..true || false);
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:204:5
+  --> $DIR/disallowed-positions.rs:203:5
    |
 LL | fn outside_if_and_while_expr() {
    |                                - help: try adding a return type: `-> &bool`
@@ -951,14 +942,14 @@ LL |     &let 0 = 0
    |     ^^^^^^^^^^ expected `()`, found `&bool`
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/disallowed-positions.rs:177:17
+  --> $DIR/disallowed-positions.rs:176:17
    |
 LL |         let 0 = 0?;
    |                 ^^ the `?` operator cannot be applied to type `{integer}`
    |
    = help: the trait `Try` is not implemented for `{integer}`
 
-error: aborting due to 103 previous errors; 1 warning emitted
+error: aborting due to 103 previous errors
 
 Some errors have detailed explanations: E0277, E0308, E0600, E0614.
 For more information about an error, try `rustc --explain E0277`.
diff --git a/src/test/ui/rfc-2497-if-let-chains/feature-gate.rs b/src/test/ui/rfc-2497-if-let-chains/feature-gate.rs
index 2b4259e9dc1..53fec8316e7 100644
--- a/src/test/ui/rfc-2497-if-let-chains/feature-gate.rs
+++ b/src/test/ui/rfc-2497-if-let-chains/feature-gate.rs
@@ -12,79 +12,79 @@ fn _if() {
     if let 0 = 1 {} // Stable!
 
     if (let 0 = 1) {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 
     if (((let 0 = 1))) {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 
     if true && let 0 = 1 {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 
     if let 0 = 1 && true {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 
     if (let 0 = 1) && true {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 
     if true && (let 0 = 1) {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 
     if (let 0 = 1) && (let 0 = 1) {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
-    //~| ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
+    //~| ERROR `let` expressions in this position are unstable [E0658]
 
     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
-    //~| ERROR `let` expressions in this position are experimental [E0658]
-    //~| ERROR `let` expressions in this position are experimental [E0658]
-    //~| ERROR `let` expressions in this position are experimental [E0658]
-    //~| ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
+    //~| ERROR `let` expressions in this position are unstable [E0658]
+    //~| ERROR `let` expressions in this position are unstable [E0658]
+    //~| ERROR `let` expressions in this position are unstable [E0658]
+    //~| ERROR `let` expressions in this position are unstable [E0658]
 
     if let Range { start: _, end: _ } = (true..true) && false {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 }
 
 fn _while() {
     while let 0 = 1 {} // Stable!
 
     while (let 0 = 1) {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 
     while (((let 0 = 1))) {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 
     while true && let 0 = 1 {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 
     while let 0 = 1 && true {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 
     while (let 0 = 1) && true {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 
     while true && (let 0 = 1) {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 
     while (let 0 = 1) && (let 0 = 1) {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
-    //~| ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
+    //~| ERROR `let` expressions in this position are unstable [E0658]
 
     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
-    //~| ERROR `let` expressions in this position are experimental [E0658]
-    //~| ERROR `let` expressions in this position are experimental [E0658]
-    //~| ERROR `let` expressions in this position are experimental [E0658]
-    //~| ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
+    //~| ERROR `let` expressions in this position are unstable [E0658]
+    //~| ERROR `let` expressions in this position are unstable [E0658]
+    //~| ERROR `let` expressions in this position are unstable [E0658]
+    //~| ERROR `let` expressions in this position are unstable [E0658]
 
     while let Range { start: _, end: _ } = (true..true) && false {}
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 }
 
 fn _macros() {
     macro_rules! noop_expr { ($e:expr) => {}; }
 
     noop_expr!((let 0 = 1));
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
 
     macro_rules! use_expr {
         ($e:expr) => {
@@ -93,11 +93,11 @@ fn _macros() {
         }
     }
     use_expr!((let 0 = 1 && 0 == 0));
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
     use_expr!((let 0 = 1));
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
     #[cfg(FALSE)] (let 0 = 1);
-    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
     use_expr!(let 0 = 1);
     //~^ ERROR no rules expected the token `let`
     // ^--- FIXME(53667): Consider whether `Let` can be added to `ident_can_begin_expr`.
diff --git a/src/test/ui/rfc-2497-if-let-chains/feature-gate.stderr b/src/test/ui/rfc-2497-if-let-chains/feature-gate.stderr
index 180eee0cadf..458826498fe 100644
--- a/src/test/ui/rfc-2497-if-let-chains/feature-gate.stderr
+++ b/src/test/ui/rfc-2497-if-let-chains/feature-gate.stderr
@@ -7,7 +7,7 @@ LL |     macro_rules! use_expr {
 LL |     use_expr!(let 0 = 1);
    |               ^^^ no rules expected this token in macro call
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:14:9
    |
 LL |     if (let 0 = 1) {}
@@ -15,9 +15,8 @@ LL |     if (let 0 = 1) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:17:11
    |
 LL |     if (((let 0 = 1))) {}
@@ -25,9 +24,8 @@ LL |     if (((let 0 = 1))) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:20:16
    |
 LL |     if true && let 0 = 1 {}
@@ -35,9 +33,8 @@ LL |     if true && let 0 = 1 {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:23:8
    |
 LL |     if let 0 = 1 && true {}
@@ -45,9 +42,8 @@ LL |     if let 0 = 1 && true {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:26:9
    |
 LL |     if (let 0 = 1) && true {}
@@ -55,9 +51,8 @@ LL |     if (let 0 = 1) && true {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:29:17
    |
 LL |     if true && (let 0 = 1) {}
@@ -65,9 +60,8 @@ LL |     if true && (let 0 = 1) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:32:9
    |
 LL |     if (let 0 = 1) && (let 0 = 1) {}
@@ -75,9 +69,8 @@ LL |     if (let 0 = 1) && (let 0 = 1) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:32:24
    |
 LL |     if (let 0 = 1) && (let 0 = 1) {}
@@ -85,9 +78,8 @@ LL |     if (let 0 = 1) && (let 0 = 1) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:36:8
    |
 LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
@@ -95,9 +87,8 @@ LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:36:21
    |
 LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
@@ -105,9 +96,8 @@ LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:36:35
    |
 LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
@@ -115,9 +105,8 @@ LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:36:48
    |
 LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
@@ -125,9 +114,8 @@ LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:36:61
    |
 LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
@@ -135,9 +123,8 @@ LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:43:8
    |
 LL |     if let Range { start: _, end: _ } = (true..true) && false {}
@@ -145,9 +132,8 @@ LL |     if let Range { start: _, end: _ } = (true..true) && false {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:50:12
    |
 LL |     while (let 0 = 1) {}
@@ -155,9 +141,8 @@ LL |     while (let 0 = 1) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:53:14
    |
 LL |     while (((let 0 = 1))) {}
@@ -165,9 +150,8 @@ LL |     while (((let 0 = 1))) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:56:19
    |
 LL |     while true && let 0 = 1 {}
@@ -175,9 +159,8 @@ LL |     while true && let 0 = 1 {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:59:11
    |
 LL |     while let 0 = 1 && true {}
@@ -185,9 +168,8 @@ LL |     while let 0 = 1 && true {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:62:12
    |
 LL |     while (let 0 = 1) && true {}
@@ -195,9 +177,8 @@ LL |     while (let 0 = 1) && true {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:65:20
    |
 LL |     while true && (let 0 = 1) {}
@@ -205,9 +186,8 @@ LL |     while true && (let 0 = 1) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:68:12
    |
 LL |     while (let 0 = 1) && (let 0 = 1) {}
@@ -215,9 +195,8 @@ LL |     while (let 0 = 1) && (let 0 = 1) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:68:27
    |
 LL |     while (let 0 = 1) && (let 0 = 1) {}
@@ -225,9 +204,8 @@ LL |     while (let 0 = 1) && (let 0 = 1) {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:72:11
    |
 LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
@@ -235,9 +213,8 @@ LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:72:24
    |
 LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
@@ -245,9 +222,8 @@ LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:72:38
    |
 LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
@@ -255,9 +231,8 @@ LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:72:51
    |
 LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
@@ -265,9 +240,8 @@ LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:72:64
    |
 LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
@@ -275,9 +249,8 @@ LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:79:11
    |
 LL |     while let Range { start: _, end: _ } = (true..true) && false {}
@@ -285,9 +258,8 @@ LL |     while let Range { start: _, end: _ } = (true..true) && false {}
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:99:20
    |
 LL |     #[cfg(FALSE)] (let 0 = 1);
@@ -295,9 +267,8 @@ LL |     #[cfg(FALSE)] (let 0 = 1);
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:86:17
    |
 LL |     noop_expr!((let 0 = 1));
@@ -305,9 +276,8 @@ LL |     noop_expr!((let 0 = 1));
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:95:16
    |
 LL |     use_expr!((let 0 = 1 && 0 == 0));
@@ -315,9 +285,8 @@ LL |     use_expr!((let 0 = 1 && 0 == 0));
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
-error[E0658]: `let` expressions in this position are experimental
+error[E0658]: `let` expressions in this position are unstable
   --> $DIR/feature-gate.rs:97:16
    |
 LL |     use_expr!((let 0 = 1));
@@ -325,7 +294,6 @@ LL |     use_expr!((let 0 = 1));
    |
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
-   = help: you can write `matches!(<expr>, <pattern>)` instead of `let <pattern> = <expr>`
 
 error: aborting due to 33 previous errors
 
diff --git a/src/test/ui/rfc-2497-if-let-chains/irrefutable-lets.rs b/src/test/ui/rfc-2497-if-let-chains/irrefutable-lets.rs
new file mode 100644
index 00000000000..5915cb9df26
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/irrefutable-lets.rs
@@ -0,0 +1,27 @@
+// check-pass
+
+#![feature(let_chains)]
+
+use std::ops::Range;
+
+fn main() {
+    let opt = Some(None..Some(1));
+
+    if let first = &opt && let Some(ref second) = first && let None = second.start {
+    }
+    if let Some(ref first) = opt && let second = first && let _third = second {
+    }
+    if let Some(ref first) = opt
+        && let Range { start: local_start, end: _ } = first
+        && let None = local_start {
+    }
+
+    while let first = &opt && let Some(ref second) = first && let None = second.start {
+    }
+    while let Some(ref first) = opt && let second = first && let _third = second {
+    }
+    while let Some(ref first) = opt
+        && let Range { start: local_start, end: _ } = first
+        && let None = local_start {
+    }
+}
diff --git a/src/test/ui/rfc-2497-if-let-chains/issue-88498.rs b/src/test/ui/rfc-2497-if-let-chains/issue-88498.rs
new file mode 100644
index 00000000000..3eb8a9ad060
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/issue-88498.rs
@@ -0,0 +1,16 @@
+// check-pass
+
+pub enum UnOp {
+    Not(Vec<()>),
+}
+
+pub fn foo() {
+    if let Some(x) = None {
+        match x {
+            UnOp::Not(_) => {}
+        }
+    }
+}
+
+fn main() {
+}
diff --git a/src/test/ui/rfc-2497-if-let-chains/issue-90722.rs b/src/test/ui/rfc-2497-if-let-chains/issue-90722.rs
new file mode 100644
index 00000000000..6b7d8835650
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/issue-90722.rs
@@ -0,0 +1,11 @@
+// check-pass
+
+#![feature(let_chains)]
+
+fn main() {
+    let x = Some(vec!["test"]);
+
+    if let Some(v) = x && v.is_empty() {
+        println!("x == Some([])");
+    }
+}
diff --git a/src/test/ui/rfc-2497-if-let-chains/issue-92145.rs b/src/test/ui/rfc-2497-if-let-chains/issue-92145.rs
new file mode 100644
index 00000000000..7c7e31f4db4
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/issue-92145.rs
@@ -0,0 +1,11 @@
+// check-pass
+
+#![feature(let_chains)]
+
+fn main() {
+    let opt = Some("foo bar");
+
+    if true && let Some(x) = opt {
+        println!("{}", x);
+    }
+}
diff --git a/src/test/ui/rfc-2497-if-let-chains/no-double-assigments.rs b/src/test/ui/rfc-2497-if-let-chains/no-double-assigments.rs
new file mode 100644
index 00000000000..6b91c455e0e
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/no-double-assigments.rs
@@ -0,0 +1,9 @@
+// check-pass
+
+fn main() {
+    loop {
+        // [1][0] should leave top scope
+        if true && [1][0] == 1 && true {
+        }
+    }
+}
diff --git a/src/test/ui/rfc-2497-if-let-chains/then-else-blocks.rs b/src/test/ui/rfc-2497-if-let-chains/then-else-blocks.rs
new file mode 100644
index 00000000000..0856a105206
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/then-else-blocks.rs
@@ -0,0 +1,35 @@
+// run-pass
+
+#![feature(let_chains)]
+
+fn check_if_let(opt: Option<Option<Option<i32>>>, value: i32) -> bool {
+    if let Some(first) = opt
+        && let Some(second) = first
+        && let Some(third) = second
+        && third == value
+    {
+        true
+    }
+    else {
+        false
+    }
+}
+
+fn check_while_let(opt: Option<Option<Option<i32>>>, value: i32) -> bool {
+    while let Some(first) = opt
+        && let Some(second) = first
+        && let Some(third) = second
+        && third == value
+    {
+        return true;
+    }
+    false
+}
+
+fn main() {
+    assert_eq!(check_if_let(Some(Some(Some(1))), 1), true);
+    assert_eq!(check_if_let(Some(Some(Some(1))), 9), false);
+
+    assert_eq!(check_while_let(Some(Some(Some(1))), 1), true);
+    assert_eq!(check_while_let(Some(Some(Some(1))), 9), false);
+}