Auto merge of #63575 - Centril:rollup-anlv9g5, r=Centril

Rollup of 11 pull requests

Successful merges:

 - #62984 (Add lint for excess trailing semicolons)
 - #63075 (Miri: Check that a ptr is aligned and inbounds already when evaluating `*`)
 - #63490 (libsyntax: cleanup and refactor `pat.rs`)
 - #63507 (When needing type annotations in local bindings, account for impl Trait and closures)
 - #63509 (Point at the right enclosing scope when using `await` in non-async fn)
 - #63528 (syntax: Remove `DummyResult::expr_only`)
 - #63537 (expand: Unimplement `MutVisitor` on `MacroExpander`)
 - #63542 (Add NodeId for Arm, Field and FieldPat)
 - #63543 (Merge Variant and Variant_)
 - #63560 (move test that shouldn't be in test/run-pass/)
 - #63570 (Adjust tracking issues for `MaybeUninit<T>` gates)

Failed merges:

r? @ghost

16 files changed, 321 insertions, 278 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 052eb55b408..f0f090c8e89 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -608,6 +608,7 @@ pub struct FieldPat {
     pub pat: P<Pat>,
     pub is_shorthand: bool,
     pub attrs: ThinVec<Attribute>,
+    pub id: NodeId,
 }
 
 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
@@ -925,6 +926,7 @@ pub struct Arm {
     pub guard: Option<P<Expr>>,
     pub body: P<Expr>,
     pub span: Span,
+    pub id: NodeId,
 }
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
@@ -934,6 +936,7 @@ pub struct Field {
     pub span: Span,
     pub is_shorthand: bool,
     pub attrs: ThinVec<Attribute>,
+    pub id: NodeId,
 }
 
 pub type SpannedIdent = Spanned<Ident>;
@@ -2038,7 +2041,7 @@ pub struct EnumDef {
 }
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
-pub struct Variant_ {
+pub struct Variant {
     /// Name of the variant.
     pub ident: Ident,
     /// Attributes of the variant.
@@ -2049,10 +2052,10 @@ pub struct Variant_ {
     pub data: VariantData,
     /// Explicit discriminant, e.g., `Foo = 1`.
     pub disr_expr: Option<AnonConst>,
+    /// Span
+    pub span: Span,
 }
 
-pub type Variant = Spanned<Variant_>;
-
 /// Part of `use` item to the right of its prefix.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum UseTreeKind {
diff --git a/src/libsyntax/attr/mod.rs b/src/libsyntax/attr/mod.rs
index a9d3227b3a8..70b1d3fc73b 100644
--- a/src/libsyntax/attr/mod.rs
+++ b/src/libsyntax/attr/mod.rs
@@ -712,7 +712,7 @@ macro_rules! derive_has_attrs {
 
 derive_has_attrs! {
     Item, Expr, Local, ast::ForeignItem, ast::StructField, ast::ImplItem, ast::TraitItem, ast::Arm,
-    ast::Field, ast::FieldPat, ast::Variant_, ast::Arg
+    ast::Field, ast::FieldPat, ast::Variant, ast::Arg
 }
 
 pub fn inject(mut krate: ast::Crate, parse_sess: &ParseSess, attrs: &[String]) -> ast::Crate {
diff --git a/src/libsyntax/config.rs b/src/libsyntax/config.rs
index 1ab367f73c1..7eeea4e7bdf 100644
--- a/src/libsyntax/config.rs
+++ b/src/libsyntax/config.rs
@@ -260,7 +260,7 @@ impl<'a> StripUnconfigured<'a> {
             ast::ItemKind::Enum(ast::EnumDef { variants }, _generics) => {
                 variants.flat_map_in_place(|variant| self.configure(variant));
                 for variant in variants {
-                    self.configure_variant_data(&mut variant.node.data);
+                    self.configure_variant_data(&mut variant.data);
                 }
             }
             _ => {}
diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 7f4feff6be6..6886b4bf421 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -405,7 +405,6 @@ impl MacResult for MacEager {
 /// after hitting errors.
 #[derive(Copy, Clone)]
 pub struct DummyResult {
-    expr_only: bool,
     is_error: bool,
     span: Span,
 }
@@ -416,21 +415,12 @@ impl DummyResult {
     /// Use this as a return value after hitting any errors and
     /// calling `span_err`.
     pub fn any(span: Span) -> Box<dyn MacResult+'static> {
-        Box::new(DummyResult { expr_only: false, is_error: true, span })
+        Box::new(DummyResult { is_error: true, span })
     }
 
     /// Same as `any`, but must be a valid fragment, not error.
     pub fn any_valid(span: Span) -> Box<dyn MacResult+'static> {
-        Box::new(DummyResult { expr_only: false, is_error: false, span })
-    }
-
-    /// Creates a default MacResult that can only be an expression.
-    ///
-    /// Use this for macros that must expand to an expression, so even
-    /// if an error is encountered internally, the user will receive
-    /// an error that they also used it in the wrong place.
-    pub fn expr(span: Span) -> Box<dyn MacResult+'static> {
-        Box::new(DummyResult { expr_only: true, is_error: true, span })
+        Box::new(DummyResult { is_error: false, span })
     }
 
     /// A plain dummy expression.
@@ -472,36 +462,19 @@ impl MacResult for DummyResult {
     }
 
     fn make_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
-        // this code needs a comment... why not always just return the Some() ?
-        if self.expr_only {
-            None
-        } else {
-            Some(SmallVec::new())
-        }
+        Some(SmallVec::new())
     }
 
     fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVec<[ast::ImplItem; 1]>> {
-        if self.expr_only {
-            None
-        } else {
-            Some(SmallVec::new())
-        }
+        Some(SmallVec::new())
     }
 
     fn make_trait_items(self: Box<DummyResult>) -> Option<SmallVec<[ast::TraitItem; 1]>> {
-        if self.expr_only {
-            None
-        } else {
-            Some(SmallVec::new())
-        }
+        Some(SmallVec::new())
     }
 
     fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> {
-        if self.expr_only {
-            None
-        } else {
-            Some(SmallVec::new())
-        }
+        Some(SmallVec::new())
     }
 
     fn make_stmts(self: Box<DummyResult>) -> Option<SmallVec<[ast::Stmt; 1]>> {
@@ -947,8 +920,10 @@ pub fn expr_to_spanned_string<'a>(
     // Update `expr.span`'s ctxt now in case expr is an `include!` macro invocation.
     expr.span = expr.span.apply_mark(cx.current_expansion.id);
 
-    // we want to be able to handle e.g., `concat!("foo", "bar")`
-    cx.expander().visit_expr(&mut expr);
+    // Perform eager expansion on the expression.
+    // We want to be able to handle e.g., `concat!("foo", "bar")`.
+    let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
+
     Err(match expr.node {
         ast::ExprKind::Lit(ref l) => match l.node {
             ast::LitKind::Str(s, style) => return Ok(respan(expr.span, (s, style))),
@@ -1013,8 +988,12 @@ pub fn get_exprs_from_tts(cx: &mut ExtCtxt<'_>,
     let mut p = cx.new_parser_from_tts(tts);
     let mut es = Vec::new();
     while p.token != token::Eof {
-        let mut expr = panictry!(p.parse_expr());
-        cx.expander().visit_expr(&mut expr);
+        let expr = panictry!(p.parse_expr());
+
+        // Perform eager expansion on the expression.
+        // We want to be able to handle e.g., `concat!("foo", "bar")`.
+        let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
+
         es.push(expr);
         if p.eat(&token::Comma) {
             continue;
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index 22962499a2b..f18cf86243e 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -403,6 +403,7 @@ impl<'a> ExtCtxt<'a> {
             span,
             is_shorthand: false,
             attrs: ThinVec::new(),
+            id: ast::DUMMY_NODE_ID,
         }
     }
     pub fn expr_struct(
@@ -612,6 +613,7 @@ impl<'a> ExtCtxt<'a> {
             guard: None,
             body: expr,
             span,
+            id: ast::DUMMY_NODE_ID,
         }
     }
 
@@ -781,14 +783,14 @@ impl<'a> ExtCtxt<'a> {
             ast::VariantData::Tuple(fields, ast::DUMMY_NODE_ID)
         };
 
-        respan(span,
-               ast::Variant_ {
-                   ident,
-                   id: ast::DUMMY_NODE_ID,
-                   attrs: Vec::new(),
-                   data: vdata,
-                   disr_expr: None,
-               })
+        ast::Variant {
+            attrs: Vec::new(),
+            data: vdata,
+            disr_expr: None,
+            id: ast::DUMMY_NODE_ID,
+            ident,
+            span,
+        }
     }
 
     pub fn item_enum_poly(&self, span: Span, name: Ident,
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 9a3195b1165..402b42dfbc8 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -116,18 +116,6 @@ macro_rules! ast_fragments {
             }
         }
 
-        impl<'a, 'b> MutVisitor for MacroExpander<'a, 'b> {
-            fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
-                self.expand_fragment(AstFragment::OptExpr(Some(expr))).make_opt_expr()
-            }
-            $($(fn $mut_visit_ast(&mut self, ast: &mut $AstTy) {
-                visit_clobber(ast, |ast| self.expand_fragment(AstFragment::$Kind(ast)).$make_ast());
-            })?)*
-            $($(fn $flat_map_ast_elt(&mut self, ast_elt: <$AstTy as IntoIterator>::Item) -> $AstTy {
-                self.expand_fragment(AstFragment::$Kind(smallvec![ast_elt])).$make_ast()
-            })?)*
-        }
-
         impl<'a> MacResult for crate::ext::tt::macro_rules::ParserAnyMacro<'a> {
             $(fn $make_ast(self: Box<crate::ext::tt::macro_rules::ParserAnyMacro<'a>>)
                            -> Option<$AstTy> {
@@ -265,7 +253,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
             tokens: None,
         })]);
 
-        match self.expand_fragment(krate_item).make_items().pop().map(P::into_inner) {
+        match self.fully_expand_fragment(krate_item).make_items().pop().map(P::into_inner) {
             Some(ast::Item { attrs, node: ast::ItemKind::Mod(module), .. }) => {
                 krate.attrs = attrs;
                 krate.module = module;
@@ -285,8 +273,8 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
         krate
     }
 
-    // Fully expand all macro invocations in this AST fragment.
-    fn expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
+    // Recursively expand all macro invocations in this AST fragment.
+    pub fn fully_expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
         let orig_expansion_data = self.cx.current_expansion.clone();
         self.cx.current_expansion.depth = 0;
 
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 08a113b53d0..8a56ae13b6f 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -1956,7 +1956,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
 
             ast::ItemKind::Enum(ast::EnumDef{ref variants, ..}, ..) => {
                 for variant in variants {
-                    match (&variant.node.data, &variant.node.disr_expr) {
+                    match (&variant.data, &variant.disr_expr) {
                         (ast::VariantData::Unit(..), _) => {},
                         (_, Some(disr_expr)) =>
                             gate_feature_post!(
diff --git a/src/libsyntax/mut_visit.rs b/src/libsyntax/mut_visit.rs
index be04c6a76b0..82446989997 100644
--- a/src/libsyntax/mut_visit.rs
+++ b/src/libsyntax/mut_visit.rs
@@ -383,10 +383,11 @@ pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
 }
 
 pub fn noop_visit_arm<T: MutVisitor>(
-    Arm { attrs, pats, guard, body, span }: &mut Arm,
+    Arm { attrs, pats, guard, body, span, id }: &mut Arm,
     vis: &mut T,
 ) {
     visit_attrs(attrs, vis);
+    vis.visit_id(id);
     visit_vec(pats, |pat| vis.visit_pat(pat));
     visit_opt(guard, |guard| vis.visit_expr(guard));
     vis.visit_expr(body);
@@ -455,7 +456,7 @@ pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis:
 }
 
 pub fn noop_visit_variant<T: MutVisitor>(variant: &mut Variant, vis: &mut T) {
-    let Spanned { node: Variant_ { ident, attrs, id, data, disr_expr }, span } = variant;
+    let Variant { ident, attrs, id, data, disr_expr, span } = variant;
     vis.visit_ident(ident);
     visit_attrs(attrs, vis);
     vis.visit_id(id);
@@ -808,9 +809,10 @@ pub fn noop_visit_struct_field<T: MutVisitor>(f: &mut StructField, visitor: &mut
 }
 
 pub fn noop_visit_field<T: MutVisitor>(f: &mut Field, vis: &mut T) {
-    let Field { ident, expr, span, is_shorthand: _, attrs } = f;
+    let Field { ident, expr, span, is_shorthand: _, attrs, id } = f;
     vis.visit_ident(ident);
     vis.visit_expr(expr);
+    vis.visit_id(id);
     vis.visit_span(span);
     visit_thin_attrs(attrs, vis);
 }
@@ -1040,8 +1042,12 @@ pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
         }
         PatKind::Struct(path, fields, _etc) => {
             vis.visit_path(path);
-            for Spanned { node: FieldPat { ident, pat, is_shorthand: _, attrs }, span } in fields {
+            for Spanned {
+                node: FieldPat { ident, pat, is_shorthand: _, attrs, id },
+                span
+            } in fields {
                 vis.visit_ident(ident);
+                vis.visit_id(id);
                 vis.visit_pat(pat);
                 visit_thin_attrs(attrs, vis);
                 vis.visit_span(span);
diff --git a/src/libsyntax/parse/diagnostics.rs b/src/libsyntax/parse/diagnostics.rs
index 730efb5ef01..1fbf28fb830 100644
--- a/src/libsyntax/parse/diagnostics.rs
+++ b/src/libsyntax/parse/diagnostics.rs
@@ -8,7 +8,6 @@ use crate::parse::parser::{BlockMode, PathStyle, SemiColonMode, TokenType, Token
 use crate::parse::token::{self, TokenKind};
 use crate::print::pprust;
 use crate::ptr::P;
-use crate::source_map::Spanned;
 use crate::symbol::{kw, sym};
 use crate::ThinVec;
 use crate::util::parser::AssocOp;
@@ -592,18 +591,18 @@ impl<'a> Parser<'a> {
 
     crate fn maybe_report_invalid_custom_discriminants(
         sess: &ParseSess,
-        variants: &[Spanned<ast::Variant_>],
+        variants: &[ast::Variant],
     ) {
-        let has_fields = variants.iter().any(|variant| match variant.node.data {
+        let has_fields = variants.iter().any(|variant| match variant.data {
             VariantData::Tuple(..) | VariantData::Struct(..) => true,
             VariantData::Unit(..) => false,
         });
 
-        let discriminant_spans = variants.iter().filter(|variant| match variant.node.data {
+        let discriminant_spans = variants.iter().filter(|variant| match variant.data {
             VariantData::Tuple(..) | VariantData::Struct(..) => false,
             VariantData::Unit(..) => true,
         })
-        .filter_map(|variant| variant.node.disr_expr.as_ref().map(|c| c.value.span))
+        .filter_map(|variant| variant.disr_expr.as_ref().map(|c| c.value.span))
         .collect::<Vec<_>>();
 
         if !discriminant_spans.is_empty() && has_fields {
@@ -618,7 +617,7 @@ impl<'a> Parser<'a> {
                 err.span_label(sp, "disallowed custom discriminant");
             }
             for variant in variants.iter() {
-                match &variant.node.data {
+                match &variant.data {
                     VariantData::Struct(..) => {
                         err.span_label(
                             variant.span,
diff --git a/src/libsyntax/parse/parser/expr.rs b/src/libsyntax/parse/parser/expr.rs
index 5376ac2eeee..7b98d7a1801 100644
--- a/src/libsyntax/parse/parser/expr.rs
+++ b/src/libsyntax/parse/parser/expr.rs
@@ -1448,6 +1448,7 @@ impl<'a> Parser<'a> {
             guard,
             body: expr,
             span: lo.to(hi),
+            id: ast::DUMMY_NODE_ID,
         })
     }
 
@@ -1603,6 +1604,7 @@ impl<'a> Parser<'a> {
                         expr: self.mk_expr(self.token.span, ExprKind::Err, ThinVec::new()),
                         is_shorthand: false,
                         attrs: ThinVec::new(),
+                        id: ast::DUMMY_NODE_ID,
                     });
                 }
             }
@@ -1688,6 +1690,7 @@ impl<'a> Parser<'a> {
             expr,
             is_shorthand,
             attrs: attrs.into(),
+            id: ast::DUMMY_NODE_ID,
         })
     }
 
diff --git a/src/libsyntax/parse/parser/item.rs b/src/libsyntax/parse/parser/item.rs
index e85ef9cc974..60873ecb134 100644
--- a/src/libsyntax/parse/parser/item.rs
+++ b/src/libsyntax/parse/parser/item.rs
@@ -1564,14 +1564,15 @@ impl<'a> Parser<'a> {
                 None
             };
 
-            let vr = ast::Variant_ {
+            let vr = ast::Variant {
                 ident,
                 id: ast::DUMMY_NODE_ID,
                 attrs: variant_attrs,
                 data: struct_def,
                 disr_expr,
+                span: vlo.to(self.prev_span),
             };
-            variants.push(respan(vlo.to(self.prev_span), vr));
+            variants.push(vr);
 
             if !self.eat(&token::Comma) {
                 if self.token.is_ident() && !self.token.is_reserved_ident() {
diff --git a/src/libsyntax/parse/parser/pat.rs b/src/libsyntax/parse/parser/pat.rs
index 5cc428a4df1..40aa8d7b46f 100644
--- a/src/libsyntax/parse/parser/pat.rs
+++ b/src/libsyntax/parse/parser/pat.rs
@@ -3,7 +3,7 @@ use super::{Parser, PResult, PathStyle};
 use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole};
 use crate::ptr::P;
 use crate::ast::{self, Attribute, Pat, PatKind, FieldPat, RangeEnd, RangeSyntax, Mac_};
-use crate::ast::{BindingMode, Ident, Mutability, Expr, ExprKind};
+use crate::ast::{BindingMode, Ident, Mutability, Path, QSelf, Expr, ExprKind};
 use crate::parse::token::{self};
 use crate::print::pprust;
 use crate::source_map::{respan, Span, Spanned};
@@ -108,93 +108,52 @@ impl<'a> Parser<'a> {
         maybe_whole!(self, NtPat, |x| x);
 
         let lo = self.token.span;
-        let pat;
-        match self.token.kind {
-            token::BinOp(token::And) | token::AndAnd => {
-                // Parse &pat / &mut pat
-                self.expect_and()?;
-                let mutbl = self.parse_mutability();
-                if let token::Lifetime(name) = self.token.kind {
-                    let mut err = self.fatal(&format!("unexpected lifetime `{}` in pattern", name));
-                    err.span_label(self.token.span, "unexpected lifetime");
-                    return Err(err);
-                }
-                let subpat = self.parse_pat_with_range_pat(false, expected)?;
-                pat = PatKind::Ref(subpat, mutbl);
-            }
-            token::OpenDelim(token::Paren) => {
-                // Parse a tuple or parenthesis pattern.
-                let (fields, trailing_comma) = self.parse_paren_comma_seq(|p| p.parse_pat(None))?;
-
-                // Here, `(pat,)` is a tuple pattern.
-                // For backward compatibility, `(..)` is a tuple pattern as well.
-                pat = if fields.len() == 1 && !(trailing_comma || fields[0].is_rest()) {
-                    PatKind::Paren(fields.into_iter().nth(0).unwrap())
-                } else {
-                    PatKind::Tuple(fields)
-                };
-            }
+        let pat = match self.token.kind {
+            token::BinOp(token::And) | token::AndAnd => self.parse_pat_deref(expected)?,
+            token::OpenDelim(token::Paren) => self.parse_pat_tuple_or_parens()?,
             token::OpenDelim(token::Bracket) => {
                 // Parse `[pat, pat,...]` as a slice pattern.
-                let (slice, _) = self.parse_delim_comma_seq(token::Bracket, |p| p.parse_pat(None))?;
-                pat = PatKind::Slice(slice);
+                PatKind::Slice(self.parse_delim_comma_seq(token::Bracket, |p| p.parse_pat(None))?.0)
             }
             token::DotDot => {
                 self.bump();
-                pat = if self.is_pat_range_end_start() {
+                if self.is_pat_range_end_start() {
                     // Parse `..42` for recovery.
                     self.parse_pat_range_to(RangeEnd::Excluded, "..")?
                 } else {
                     // A rest pattern `..`.
                     PatKind::Rest
-                };
+                }
             }
             token::DotDotEq => {
                 // Parse `..=42` for recovery.
                 self.bump();
-                pat = self.parse_pat_range_to(RangeEnd::Included(RangeSyntax::DotDotEq), "..=")?;
+                self.parse_pat_range_to(RangeEnd::Included(RangeSyntax::DotDotEq), "..=")?
             }
             token::DotDotDot => {
                 // Parse `...42` for recovery.
                 self.bump();
-                pat = self.parse_pat_range_to(RangeEnd::Included(RangeSyntax::DotDotDot), "...")?;
+                self.parse_pat_range_to(RangeEnd::Included(RangeSyntax::DotDotDot), "...")?
             }
             // At this point, token != &, &&, (, [
             _ => if self.eat_keyword(kw::Underscore) {
                 // Parse _
-                pat = PatKind::Wild;
+                PatKind::Wild
             } else if self.eat_keyword(kw::Mut) {
-                // Parse mut ident @ pat / mut ref ident @ pat
-                let mutref_span = self.prev_span.to(self.token.span);
-                let binding_mode = if self.eat_keyword(kw::Ref) {
-                    self.diagnostic()
-                        .struct_span_err(mutref_span, "the order of `mut` and `ref` is incorrect")
-                        .span_suggestion(
-                            mutref_span,
-                            "try switching the order",
-                            "ref mut".into(),
-                            Applicability::MachineApplicable
-                        ).emit();
-                    BindingMode::ByRef(Mutability::Mutable)
-                } else {
-                    BindingMode::ByValue(Mutability::Mutable)
-                };
-                pat = self.parse_pat_ident(binding_mode)?;
+                self.recover_pat_ident_mut_first()?
             } else if self.eat_keyword(kw::Ref) {
                 // Parse ref ident @ pat / ref mut ident @ pat
                 let mutbl = self.parse_mutability();
-                pat = self.parse_pat_ident(BindingMode::ByRef(mutbl))?;
+                self.parse_pat_ident(BindingMode::ByRef(mutbl))?
             } else if self.eat_keyword(kw::Box) {
-                // Parse box pat
-                let subpat = self.parse_pat_with_range_pat(false, None)?;
-                pat = PatKind::Box(subpat);
+                // Parse `box pat`
+                PatKind::Box(self.parse_pat_with_range_pat(false, None)?)
             } else if self.token.is_ident() && !self.token.is_reserved_ident() &&
                       self.parse_as_ident() {
-                // Parse ident @ pat
+                // Parse `ident @ pat`
                 // This can give false positives and parse nullary enums,
-                // they are dealt with later in resolve
-                let binding_mode = BindingMode::ByValue(Mutability::Immutable);
-                pat = self.parse_pat_ident(binding_mode)?;
+                // they are dealt with later in resolve.
+                self.parse_pat_ident(BindingMode::ByValue(Mutability::Immutable))?
             } else if self.token.is_path_start() {
                 // Parse pattern starting with a path
                 let (qself, path) = if self.eat_lt() {
@@ -206,136 +165,186 @@ impl<'a> Parser<'a> {
                     (None, self.parse_path(PathStyle::Expr)?)
                 };
                 match self.token.kind {
-                    token::Not if qself.is_none() => {
-                        // Parse macro invocation
-                        self.bump();
-                        let (delim, tts) = self.expect_delimited_token_tree()?;
-                        let mac = respan(lo.to(self.prev_span), Mac_ {
-                            path,
-                            tts,
-                            delim,
-                            prior_type_ascription: self.last_type_ascription,
-                        });
-                        pat = PatKind::Mac(mac);
-                    }
+                    token::Not if qself.is_none() => self.parse_pat_mac_invoc(lo, path)?,
                     token::DotDotDot | token::DotDotEq | token::DotDot => {
-                        let (end_kind, form) = match self.token.kind {
-                            token::DotDot => (RangeEnd::Excluded, ".."),
-                            token::DotDotDot => (RangeEnd::Included(RangeSyntax::DotDotDot), "..."),
-                            token::DotDotEq => (RangeEnd::Included(RangeSyntax::DotDotEq), "..="),
-                            _ => panic!("can only parse `..`/`...`/`..=` for ranges \
-                                         (checked above)"),
-                        };
-                        let op_span = self.token.span;
-                        // Parse range
-                        let span = lo.to(self.prev_span);
-                        let begin = self.mk_expr(span, ExprKind::Path(qself, path), ThinVec::new());
-                        self.bump();
-                        let end = self.parse_pat_range_end_opt(&begin, form)?;
-                        pat = PatKind::Range(begin, end, respan(op_span, end_kind));
-                    }
-                    token::OpenDelim(token::Brace) => {
-                        if qself.is_some() {
-                            let msg = "unexpected `{` after qualified path";
-                            let mut err = self.fatal(msg);
-                            err.span_label(self.token.span, msg);
-                            return Err(err);
-                        }
-                        // Parse struct pattern
-                        self.bump();
-                        let (fields, etc) = self.parse_pat_fields().unwrap_or_else(|mut e| {
-                            e.emit();
-                            self.recover_stmt();
-                            (vec![], true)
-                        });
-                        self.bump();
-                        pat = PatKind::Struct(path, fields, etc);
-                    }
-                    token::OpenDelim(token::Paren) => {
-                        if qself.is_some() {
-                            let msg = "unexpected `(` after qualified path";
-                            let mut err = self.fatal(msg);
-                            err.span_label(self.token.span, msg);
-                            return Err(err);
-                        }
-                        // Parse tuple struct or enum pattern
-                        let (fields, _) = self.parse_paren_comma_seq(|p| p.parse_pat(None))?;
-                        pat = PatKind::TupleStruct(path, fields)
+                        self.parse_pat_range_starting_with_path(lo, qself, path)?
                     }
-                    _ => pat = PatKind::Path(qself, path),
+                    token::OpenDelim(token::Brace) => self.parse_pat_struct(qself, path)?,
+                    token::OpenDelim(token::Paren) => self.parse_pat_tuple_struct(qself, path)?,
+                    _ => PatKind::Path(qself, path),
                 }
             } else {
                 // Try to parse everything else as literal with optional minus
                 match self.parse_literal_maybe_minus() {
-                    Ok(begin) => {
-                        let op_span = self.token.span;
-                        if self.check(&token::DotDot) || self.check(&token::DotDotEq) ||
-                                self.check(&token::DotDotDot) {
-                            let (end_kind, form) = if self.eat(&token::DotDotDot) {
-                                (RangeEnd::Included(RangeSyntax::DotDotDot), "...")
-                            } else if self.eat(&token::DotDotEq) {
-                                (RangeEnd::Included(RangeSyntax::DotDotEq), "..=")
-                            } else if self.eat(&token::DotDot) {
-                                (RangeEnd::Excluded, "..")
-                            } else {
-                                panic!("impossible case: we already matched \
-                                        on a range-operator token")
-                            };
-                            let end = self.parse_pat_range_end_opt(&begin, form)?;
-                            pat = PatKind::Range(begin, end, respan(op_span, end_kind))
-                        } else {
-                            pat = PatKind::Lit(begin);
-                        }
-                    }
-                    Err(mut err) => {
-                        self.cancel(&mut err);
-                        let expected = expected.unwrap_or("pattern");
-                        let msg = format!(
-                            "expected {}, found {}",
-                            expected,
-                            self.this_token_descr(),
-                        );
-                        let mut err = self.fatal(&msg);
-                        err.span_label(self.token.span, format!("expected {}", expected));
-                        let sp = self.sess.source_map().start_point(self.token.span);
-                        if let Some(sp) = self.sess.ambiguous_block_expr_parse.borrow().get(&sp) {
-                            self.sess.expr_parentheses_needed(&mut err, *sp, None);
-                        }
-                        return Err(err);
+                    Ok(begin)
+                        if self.check(&token::DotDot)
+                            || self.check(&token::DotDotEq)
+                            || self.check(&token::DotDotDot) =>
+                    {
+                        self.parse_pat_range_starting_with_lit(begin)?
                     }
+                    Ok(begin) => PatKind::Lit(begin),
+                    Err(err) => return self.fatal_unexpected_non_pat(err, expected),
                 }
             }
-        }
+        };
 
         let pat = self.mk_pat(lo.to(self.prev_span), pat);
         let pat = self.maybe_recover_from_bad_qpath(pat, true)?;
 
         if !allow_range_pat {
-            match pat.node {
-                PatKind::Range(
-                    _, _, Spanned { node: RangeEnd::Included(RangeSyntax::DotDotDot), .. }
-                ) => {},
-                PatKind::Range(..) => {
-                    let mut err = self.struct_span_err(
-                        pat.span,
-                        "the range pattern here has ambiguous interpretation",
-                    );
-                    err.span_suggestion(
-                        pat.span,
-                        "add parentheses to clarify the precedence",
-                        format!("({})", pprust::pat_to_string(&pat)),
-                        // "ambiguous interpretation" implies that we have to be guessing
-                        Applicability::MaybeIncorrect
-                    );
-                    return Err(err);
-                }
-                _ => {}
-            }
+            self.ban_pat_range_if_ambiguous(&pat)?
         }
 
         Ok(pat)
     }
 
+    /// Ban a range pattern if it has an ambiguous interpretation.
+    fn ban_pat_range_if_ambiguous(&self, pat: &Pat) -> PResult<'a, ()> {
+        match pat.node {
+            PatKind::Range(
+                .., Spanned { node: RangeEnd::Included(RangeSyntax::DotDotDot), .. }
+            ) => return Ok(()),
+            PatKind::Range(..) => {}
+            _ => return Ok(()),
+        }
+
+        let mut err = self.struct_span_err(
+            pat.span,
+            "the range pattern here has ambiguous interpretation",
+        );
+        err.span_suggestion(
+            pat.span,
+            "add parentheses to clarify the precedence",
+            format!("({})", pprust::pat_to_string(&pat)),
+            // "ambiguous interpretation" implies that we have to be guessing
+            Applicability::MaybeIncorrect
+        );
+        Err(err)
+    }
+
+    /// Parse `&pat` / `&mut pat`.
+    fn parse_pat_deref(&mut self, expected: Option<&'static str>) -> PResult<'a, PatKind> {
+        self.expect_and()?;
+        let mutbl = self.parse_mutability();
+
+        if let token::Lifetime(name) = self.token.kind {
+            let mut err = self.fatal(&format!("unexpected lifetime `{}` in pattern", name));
+            err.span_label(self.token.span, "unexpected lifetime");
+            return Err(err);
+        }
+
+        let subpat = self.parse_pat_with_range_pat(false, expected)?;
+        Ok(PatKind::Ref(subpat, mutbl))
+    }
+
+    /// Parse a tuple or parenthesis pattern.
+    fn parse_pat_tuple_or_parens(&mut self) -> PResult<'a, PatKind> {
+        let (fields, trailing_comma) = self.parse_paren_comma_seq(|p| p.parse_pat(None))?;
+
+        // Here, `(pat,)` is a tuple pattern.
+        // For backward compatibility, `(..)` is a tuple pattern as well.
+        Ok(if fields.len() == 1 && !(trailing_comma || fields[0].is_rest()) {
+            PatKind::Paren(fields.into_iter().nth(0).unwrap())
+        } else {
+            PatKind::Tuple(fields)
+        })
+    }
+
+    /// Recover on `mut ref? ident @ pat` and suggest
+    /// that the order of `mut` and `ref` is incorrect.
+    fn recover_pat_ident_mut_first(&mut self) -> PResult<'a, PatKind> {
+        let mutref_span = self.prev_span.to(self.token.span);
+        let binding_mode = if self.eat_keyword(kw::Ref) {
+            self.struct_span_err(mutref_span, "the order of `mut` and `ref` is incorrect")
+                .span_suggestion(
+                    mutref_span,
+                    "try switching the order",
+                    "ref mut".into(),
+                    Applicability::MachineApplicable
+                )
+                .emit();
+            BindingMode::ByRef(Mutability::Mutable)
+        } else {
+            BindingMode::ByValue(Mutability::Mutable)
+        };
+        self.parse_pat_ident(binding_mode)
+    }
+
+    /// Parse macro invocation
+    fn parse_pat_mac_invoc(&mut self, lo: Span, path: Path) -> PResult<'a, PatKind> {
+        self.bump();
+        let (delim, tts) = self.expect_delimited_token_tree()?;
+        let mac = respan(lo.to(self.prev_span), Mac_ {
+            path,
+            tts,
+            delim,
+            prior_type_ascription: self.last_type_ascription,
+        });
+        Ok(PatKind::Mac(mac))
+    }
+
+    /// Parse a range pattern `$path $form $end?` where `$form = ".." | "..." | "..=" ;`.
+    /// The `$path` has already been parsed and the next token is the `$form`.
+    fn parse_pat_range_starting_with_path(
+        &mut self,
+        lo: Span,
+        qself: Option<QSelf>,
+        path: Path
+    ) -> PResult<'a, PatKind> {
+        let (end_kind, form) = match self.token.kind {
+            token::DotDot => (RangeEnd::Excluded, ".."),
+            token::DotDotDot => (RangeEnd::Included(RangeSyntax::DotDotDot), "..."),
+            token::DotDotEq => (RangeEnd::Included(RangeSyntax::DotDotEq), "..="),
+            _ => panic!("can only parse `..`/`...`/`..=` for ranges (checked above)"),
+        };
+        let op_span = self.token.span;
+        // Parse range
+        let span = lo.to(self.prev_span);
+        let begin = self.mk_expr(span, ExprKind::Path(qself, path), ThinVec::new());
+        self.bump();
+        let end = self.parse_pat_range_end_opt(&begin, form)?;
+        Ok(PatKind::Range(begin, end, respan(op_span, end_kind)))
+    }
+
+    /// Parse a range pattern `$literal $form $end?` where `$form = ".." | "..." | "..=" ;`.
+    /// The `$path` has already been parsed and the next token is the `$form`.
+    fn parse_pat_range_starting_with_lit(&mut self, begin: P<Expr>) -> PResult<'a, PatKind> {
+        let op_span = self.token.span;
+        let (end_kind, form) = if self.eat(&token::DotDotDot) {
+            (RangeEnd::Included(RangeSyntax::DotDotDot), "...")
+        } else if self.eat(&token::DotDotEq) {
+            (RangeEnd::Included(RangeSyntax::DotDotEq), "..=")
+        } else if self.eat(&token::DotDot) {
+            (RangeEnd::Excluded, "..")
+        } else {
+            panic!("impossible case: we already matched on a range-operator token")
+        };
+        let end = self.parse_pat_range_end_opt(&begin, form)?;
+        Ok(PatKind::Range(begin, end, respan(op_span, end_kind)))
+    }
+
+    fn fatal_unexpected_non_pat(
+        &mut self,
+        mut err: DiagnosticBuilder<'a>,
+        expected: Option<&'static str>,
+    ) -> PResult<'a, P<Pat>> {
+        self.cancel(&mut err);
+
+        let expected = expected.unwrap_or("pattern");
+        let msg = format!("expected {}, found {}", expected, self.this_token_descr());
+
+        let mut err = self.fatal(&msg);
+        err.span_label(self.token.span, format!("expected {}", expected));
+
+        let sp = self.sess.source_map().start_point(self.token.span);
+        if let Some(sp) = self.sess.ambiguous_block_expr_parse.borrow().get(&sp) {
+            self.sess.expr_parentheses_needed(&mut err, *sp, None);
+        }
+
+        Err(err)
+    }
+
     // Helper function to decide whether to parse as ident binding
     // or to try to do something more complex like range patterns.
     fn parse_as_ident(&mut self) -> bool {
@@ -421,11 +430,9 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses `ident` or `ident @ pat`.
-    /// used by the copy foo and ref foo patterns to give a good
+    /// Used by the copy foo and ref foo patterns to give a good
     /// error message when parsing mistakes like `ref foo(a, b)`.
-    fn parse_pat_ident(&mut self,
-                       binding_mode: ast::BindingMode)
-                       -> PResult<'a, PatKind> {
+    fn parse_pat_ident(&mut self, binding_mode: BindingMode) -> PResult<'a, PatKind> {
         let ident = self.parse_ident()?;
         let sub = if self.eat(&token::At) {
             Some(self.parse_pat(Some("binding pattern"))?)
@@ -433,21 +440,52 @@ impl<'a> Parser<'a> {
             None
         };
 
-        // just to be friendly, if they write something like
-        //   ref Some(i)
-        // we end up here with ( as the current token.  This shortly
-        // leads to a parse error.  Note that if there is no explicit
+        // Just to be friendly, if they write something like `ref Some(i)`,
+        // we end up here with `(` as the current token.
+        // This shortly leads to a parse error. Note that if there is no explicit
         // binding mode then we do not end up here, because the lookahead
-        // will direct us over to parse_enum_variant()
+        // will direct us over to `parse_enum_variant()`.
         if self.token == token::OpenDelim(token::Paren) {
             return Err(self.span_fatal(
                 self.prev_span,
-                "expected identifier, found enum pattern"))
+                "expected identifier, found enum pattern",
+            ))
         }
 
         Ok(PatKind::Ident(binding_mode, ident, sub))
     }
 
+    /// Parse a struct ("record") pattern (e.g. `Foo { ... }` or `Foo::Bar { ... }`).
+    fn parse_pat_struct(&mut self, qself: Option<QSelf>, path: Path) -> PResult<'a, PatKind> {
+        if qself.is_some() {
+            let msg = "unexpected `{` after qualified path";
+            let mut err = self.fatal(msg);
+            err.span_label(self.token.span, msg);
+            return Err(err);
+        }
+
+        self.bump();
+        let (fields, etc) = self.parse_pat_fields().unwrap_or_else(|mut e| {
+            e.emit();
+            self.recover_stmt();
+            (vec![], true)
+        });
+        self.bump();
+        Ok(PatKind::Struct(path, fields, etc))
+    }
+
+    /// Parse tuple struct or tuple variant pattern (e.g. `Foo(...)` or `Foo::Bar(...)`).
+    fn parse_pat_tuple_struct(&mut self, qself: Option<QSelf>, path: Path) -> PResult<'a, PatKind> {
+        if qself.is_some() {
+            let msg = "unexpected `(` after qualified path";
+            let mut err = self.fatal(msg);
+            err.span_label(self.token.span, msg);
+            return Err(err);
+        }
+        let (fields, _) = self.parse_paren_comma_seq(|p| p.parse_pat(None))?;
+        Ok(PatKind::TupleStruct(path, fields))
+    }
+
     /// Parses the fields of a struct-like pattern.
     fn parse_pat_fields(&mut self) -> PResult<'a, (Vec<Spanned<FieldPat>>, bool)> {
         let mut fields = Vec::new();
@@ -482,17 +520,7 @@ impl<'a> Parser<'a> {
                 etc = true;
                 let mut etc_sp = self.token.span;
 
-                if self.token == token::DotDotDot { // Issue #46718
-                    // Accept `...` as if it were `..` to avoid further errors
-                    self.struct_span_err(self.token.span, "expected field pattern, found `...`")
-                        .span_suggestion(
-                            self.token.span,
-                            "to omit remaining fields, use one fewer `.`",
-                            "..".to_owned(),
-                            Applicability::MachineApplicable
-                        )
-                        .emit();
-                }
+                self.recover_one_fewer_dotdot();
                 self.bump();  // `..` || `...`
 
                 if self.token == token::CloseDelim(token::Brace) {
@@ -574,6 +602,23 @@ impl<'a> Parser<'a> {
         return Ok((fields, etc));
     }
 
+    /// Recover on `...` as if it were `..` to avoid further errors.
+    /// See issue #46718.
+    fn recover_one_fewer_dotdot(&self) {
+        if self.token != token::DotDotDot {
+            return;
+        }
+
+        self.struct_span_err(self.token.span, "expected field pattern, found `...`")
+            .span_suggestion(
+                self.token.span,
+                "to omit remaining fields, use one fewer `.`",
+                "..".to_owned(),
+                Applicability::MachineApplicable
+            )
+            .emit();
+    }
+
     fn parse_pat_field(
         &mut self,
         lo: Span,
@@ -620,6 +665,7 @@ impl<'a> Parser<'a> {
                 pat: subpat,
                 is_shorthand,
                 attrs: attrs.into(),
+                id: ast::DUMMY_NODE_ID,
            }
         })
     }
diff --git a/src/libsyntax/parse/parser/stmt.rs b/src/libsyntax/parse/parser/stmt.rs
index f182edcbff4..750d8fbbddc 100644
--- a/src/libsyntax/parse/parser/stmt.rs
+++ b/src/libsyntax/parse/parser/stmt.rs
@@ -167,7 +167,22 @@ impl<'a> Parser<'a> {
                     if self.token == token::Semi {
                         unused_attrs(&attrs, self);
                         self.bump();
-                        return Ok(None);
+                        let mut last_semi = lo;
+                        while self.token == token::Semi {
+                            last_semi = self.token.span;
+                            self.bump();
+                        }
+                        // We are encoding a string of semicolons as an
+                        // an empty tuple that spans the excess semicolons
+                        // to preserve this info until the lint stage
+                        return Ok(Some(Stmt {
+                            id: ast::DUMMY_NODE_ID,
+                            span: lo.to(last_semi),
+                            node: StmtKind::Semi(self.mk_expr(lo.to(last_semi),
+                                ExprKind::Tup(Vec::new()),
+                                ThinVec::new()
+                            )),
+                        }));
                     }
 
                     if self.token == token::CloseDelim(token::Brace) {
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index bda761244d5..8b97ec3da0b 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -1402,7 +1402,7 @@ impl<'a> State<'a> {
         for v in variants {
             self.space_if_not_bol();
             self.maybe_print_comment(v.span.lo());
-            self.print_outer_attributes(&v.node.attrs);
+            self.print_outer_attributes(&v.attrs);
             self.ibox(INDENT_UNIT);
             self.print_variant(v);
             self.s.word(",");
@@ -1492,8 +1492,8 @@ impl<'a> State<'a> {
     crate fn print_variant(&mut self, v: &ast::Variant) {
         self.head("");
         let generics = ast::Generics::default();
-        self.print_struct(&v.node.data, &generics, v.node.ident, v.span, false);
-        match v.node.disr_expr {
+        self.print_struct(&v.data, &generics, v.ident, v.span, false);
+        match v.disr_expr {
             Some(ref d) => {
                 self.s.space();
                 self.word_space("=");
diff --git a/src/libsyntax/print/pprust/tests.rs b/src/libsyntax/print/pprust/tests.rs
index 082a430e0ed..25214673e69 100644
--- a/src/libsyntax/print/pprust/tests.rs
+++ b/src/libsyntax/print/pprust/tests.rs
@@ -54,14 +54,15 @@ fn test_variant_to_string() {
     with_default_globals(|| {
         let ident = ast::Ident::from_str("principal_skinner");
 
-        let var = source_map::respan(syntax_pos::DUMMY_SP, ast::Variant_ {
+        let var = ast::Variant {
             ident,
             attrs: Vec::new(),
             id: ast::DUMMY_NODE_ID,
             // making this up as I go.... ?
             data: ast::VariantData::Unit(ast::DUMMY_NODE_ID),
             disr_expr: None,
-        });
+            span: syntax_pos::DUMMY_SP,
+        };
 
         let varstr = variant_to_string(&var);
         assert_eq!(varstr, "principal_skinner");
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index 596c5b46b98..41b8ef16665 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -311,11 +311,11 @@ pub fn walk_variant<'a, V>(visitor: &mut V,
                            item_id: NodeId)
     where V: Visitor<'a>,
 {
-    visitor.visit_ident(variant.node.ident);
-    visitor.visit_variant_data(&variant.node.data, variant.node.ident,
+    visitor.visit_ident(variant.ident);
+    visitor.visit_variant_data(&variant.data, variant.ident,
                              generics, item_id, variant.span);
-    walk_list!(visitor, visit_anon_const, &variant.node.disr_expr);
-    walk_list!(visitor, visit_attribute, &variant.node.attrs);
+    walk_list!(visitor, visit_anon_const, &variant.disr_expr);
+    walk_list!(visitor, visit_attribute, &variant.attrs);
 }
 
 pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {