Auto merge of #107451 - matthiaskrgr:rollup-m4ucfu8, r=matthiaskrgr

Rollup of 11 pull requests

Successful merges:

 - #96763 (Fix maintainer validation message)
 - #106540 (Insert whitespace to avoid ident concatenation in suggestion)
 - #106763 (print why a test was ignored if its the only test specified)
 - #106769 (libtest: Print why a test was ignored if it's the only test specified.)
 - #106798 (Implement `signum` with `Ord`)
 - #107006 (Output tree representation on thir-tree)
 - #107078 (Update wording of invalid_doc_attributes docs.)
 - #107169 (Pass `--locked` to the x test tidy call)
 - #107431 (docs: remove colon from time header)
 - #107432 (rustdoc: remove unused class `has-srclink`)
 - #107448 (When stamp doesn't exist, should say Error, and print path to stamp file)

Failed merges:

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

10 files changed, 937 insertions, 7 deletions

diff --git a/compiler/rustc_driver/src/pretty.rs b/compiler/rustc_driver/src/pretty.rs
index 022051e008e..446c6832cb7 100644
--- a/compiler/rustc_driver/src/pretty.rs
+++ b/compiler/rustc_driver/src/pretty.rs
@@ -498,6 +498,21 @@ fn print_with_analysis(tcx: TyCtxt<'_>, ppm: PpMode) -> Result<(), ErrorGuarante
             out
         }
 
+        ThirFlat => {
+            let mut out = String::new();
+            abort_on_err(rustc_hir_analysis::check_crate(tcx), tcx.sess);
+            debug!("pretty printing THIR flat");
+            for did in tcx.hir().body_owners() {
+                let _ = writeln!(
+                    out,
+                    "{:?}:\n{}\n",
+                    did,
+                    tcx.thir_flat(ty::WithOptConstParam::unknown(did))
+                );
+            }
+            out
+        }
+
         _ => unreachable!(),
     };
 
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index b6481d70bc8..4a38ab2159f 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -3531,9 +3531,15 @@ declare_lint! {
     ///
     /// ### Explanation
     ///
-    /// Previously, there were very like checks being performed on `#[doc(..)]`
-    /// unlike the other attributes. It'll now catch all the issues that it
-    /// silently ignored previously.
+    /// Previously, incorrect usage of the `#[doc(..)]` attribute was not
+    /// being validated. Usually these should be rejected as a hard error,
+    /// but this lint was introduced to avoid breaking any existing
+    /// crates which included them.
+    ///
+    /// This is a [future-incompatible] lint to transition this to a hard
+    /// error in the future. See [issue #82730] for more details.
+    ///
+    /// [issue #82730]: https://github.com/rust-lang/rust/issues/82730
     pub INVALID_DOC_ATTRIBUTES,
     Warn,
     "detects invalid `#[doc(...)]` attributes",
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 3917a97db4f..1f1f4fc95b5 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -361,6 +361,13 @@ rustc_queries! {
         desc { |tcx| "constructing THIR tree for `{}`", tcx.def_path_str(key.did.to_def_id()) }
     }
 
+    /// Create a list-like THIR representation for debugging.
+    query thir_flat(key: ty::WithOptConstParam<LocalDefId>) -> String {
+        no_hash
+        arena_cache
+        desc { |tcx| "constructing flat THIR representation for `{}`", tcx.def_path_str(key.did.to_def_id()) }
+    }
+
     /// Set of all the `DefId`s in this crate that have MIR associated with
     /// them. This includes all the body owners, but also things like struct
     /// constructors.
diff --git a/compiler/rustc_middle/src/thir.rs b/compiler/rustc_middle/src/thir.rs
index 5f320708c84..6f2dac46753 100644
--- a/compiler/rustc_middle/src/thir.rs
+++ b/compiler/rustc_middle/src/thir.rs
@@ -29,6 +29,7 @@ use rustc_target::asm::InlineAsmRegOrRegClass;
 use std::fmt;
 use std::ops::Index;
 
+pub mod print;
 pub mod visit;
 
 macro_rules! thir_with_elements {
diff --git a/compiler/rustc_middle/src/thir/print.rs b/compiler/rustc_middle/src/thir/print.rs
new file mode 100644
index 00000000000..60b903e9906
--- /dev/null
+++ b/compiler/rustc_middle/src/thir/print.rs
@@ -0,0 +1,881 @@
+use crate::thir::*;
+use crate::ty::{self, TyCtxt};
+
+use std::fmt::{self, Write};
+
+impl<'tcx> TyCtxt<'tcx> {
+    pub fn thir_tree_representation<'a>(self, thir: &'a Thir<'tcx>) -> String {
+        let mut printer = ThirPrinter::new(thir);
+        printer.print();
+        printer.into_buffer()
+    }
+}
+
+struct ThirPrinter<'a, 'tcx> {
+    thir: &'a Thir<'tcx>,
+    fmt: String,
+}
+
+const INDENT: &str = "    ";
+
+macro_rules! print_indented {
+    ($writer:ident, $s:expr, $indent_lvl:expr) => {
+        let indent = (0..$indent_lvl).map(|_| INDENT).collect::<Vec<_>>().concat();
+        writeln!($writer, "{}{}", indent, $s).expect("unable to write to ThirPrinter");
+    };
+}
+
+impl<'a, 'tcx> Write for ThirPrinter<'a, 'tcx> {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        self.fmt.push_str(s);
+        Ok(())
+    }
+}
+
+impl<'a, 'tcx> ThirPrinter<'a, 'tcx> {
+    fn new(thir: &'a Thir<'tcx>) -> Self {
+        Self { thir, fmt: String::new() }
+    }
+
+    fn print(&mut self) {
+        print_indented!(self, "params: [", 0);
+        for param in self.thir.params.iter() {
+            self.print_param(param, 1);
+        }
+        print_indented!(self, "]", 0);
+
+        print_indented!(self, "body:", 0);
+        let expr = ExprId::from_usize(self.thir.exprs.len() - 1);
+        self.print_expr(expr, 1);
+    }
+
+    fn into_buffer(self) -> String {
+        self.fmt
+    }
+
+    fn print_param(&mut self, param: &Param<'tcx>, depth_lvl: usize) {
+        let Param { pat, ty, ty_span, self_kind, hir_id } = param;
+
+        print_indented!(self, "Param {", depth_lvl);
+        print_indented!(self, format!("ty: {:?}", ty), depth_lvl + 1);
+        print_indented!(self, format!("ty_span: {:?}", ty_span), depth_lvl + 1);
+        print_indented!(self, format!("self_kind: {:?}", self_kind), depth_lvl + 1);
+        print_indented!(self, format!("hir_id: {:?}", hir_id), depth_lvl + 1);
+
+        if let Some(pat) = pat {
+            print_indented!(self, "param: Some( ", depth_lvl + 1);
+            self.print_pat(pat, depth_lvl + 2);
+            print_indented!(self, ")", depth_lvl + 1);
+        } else {
+            print_indented!(self, "param: None", depth_lvl + 1);
+        }
+
+        print_indented!(self, "}", depth_lvl);
+    }
+
+    fn print_block(&mut self, block_id: BlockId, depth_lvl: usize) {
+        let Block {
+            targeted_by_break,
+            opt_destruction_scope,
+            span,
+            region_scope,
+            stmts,
+            expr,
+            safety_mode,
+        } = &self.thir.blocks[block_id];
+
+        print_indented!(self, "Block {", depth_lvl);
+        print_indented!(self, format!("targeted_by_break: {}", targeted_by_break), depth_lvl + 1);
+        print_indented!(
+            self,
+            format!("opt_destruction_scope: {:?}", opt_destruction_scope),
+            depth_lvl + 1
+        );
+        print_indented!(self, format!("span: {:?}", span), depth_lvl + 1);
+        print_indented!(self, format!("region_scope: {:?}", region_scope), depth_lvl + 1);
+        print_indented!(self, format!("safety_mode: {:?}", safety_mode), depth_lvl + 1);
+
+        if stmts.len() > 0 {
+            print_indented!(self, "stmts: [", depth_lvl + 1);
+            for stmt in stmts.iter() {
+                self.print_stmt(*stmt, depth_lvl + 2);
+            }
+            print_indented!(self, "]", depth_lvl + 1);
+        } else {
+            print_indented!(self, "stmts: []", depth_lvl + 1);
+        }
+
+        if let Some(expr_id) = expr {
+            print_indented!(self, "expr:", depth_lvl + 1);
+            self.print_expr(*expr_id, depth_lvl + 2);
+        } else {
+            print_indented!(self, "expr: []", depth_lvl + 1);
+        }
+
+        print_indented!(self, "}", depth_lvl);
+    }
+
+    fn print_stmt(&mut self, stmt_id: StmtId, depth_lvl: usize) {
+        let Stmt { kind, opt_destruction_scope } = &self.thir.stmts[stmt_id];
+
+        print_indented!(self, "Stmt {", depth_lvl);
+        print_indented!(
+            self,
+            format!("opt_destruction_scope: {:?}", opt_destruction_scope),
+            depth_lvl + 1
+        );
+
+        match kind {
+            StmtKind::Expr { scope, expr } => {
+                print_indented!(self, "kind: Expr {", depth_lvl + 1);
+                print_indented!(self, format!("scope: {:?}", scope), depth_lvl + 2);
+                print_indented!(self, "expr:", depth_lvl + 2);
+                self.print_expr(*expr, depth_lvl + 3);
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            StmtKind::Let {
+                remainder_scope,
+                init_scope,
+                pattern,
+                initializer,
+                else_block,
+                lint_level,
+            } => {
+                print_indented!(self, "kind: Let {", depth_lvl + 1);
+                print_indented!(
+                    self,
+                    format!("remainder_scope: {:?}", remainder_scope),
+                    depth_lvl + 2
+                );
+                print_indented!(self, format!("init_scope: {:?}", init_scope), depth_lvl + 2);
+
+                print_indented!(self, "pattern: ", depth_lvl + 2);
+                self.print_pat(pattern, depth_lvl + 3);
+                print_indented!(self, ",", depth_lvl + 2);
+
+                if let Some(init) = initializer {
+                    print_indented!(self, "initializer: Some(", depth_lvl + 2);
+                    self.print_expr(*init, depth_lvl + 3);
+                    print_indented!(self, ")", depth_lvl + 2);
+                } else {
+                    print_indented!(self, "initializer: None", depth_lvl + 2);
+                }
+
+                if let Some(else_block) = else_block {
+                    print_indented!(self, "else_block: Some(", depth_lvl + 2);
+                    self.print_block(*else_block, depth_lvl + 3);
+                    print_indented!(self, ")", depth_lvl + 2);
+                } else {
+                    print_indented!(self, "else_block: None", depth_lvl + 2);
+                }
+
+                print_indented!(self, format!("lint_level: {:?}", lint_level), depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+        }
+
+        print_indented!(self, "}", depth_lvl);
+    }
+
+    fn print_expr(&mut self, expr: ExprId, depth_lvl: usize) {
+        let Expr { ty, temp_lifetime, span, kind } = &self.thir[expr];
+        print_indented!(self, "Expr {", depth_lvl);
+        print_indented!(self, format!("ty: {:?}", ty), depth_lvl + 1);
+        print_indented!(self, format!("temp_lifetime: {:?}", temp_lifetime), depth_lvl + 1);
+        print_indented!(self, format!("span: {:?}", span), depth_lvl + 1);
+        print_indented!(self, "kind: ", depth_lvl + 1);
+        self.print_expr_kind(kind, depth_lvl + 2);
+        print_indented!(self, "}", depth_lvl);
+    }
+
+    fn print_expr_kind(&mut self, expr_kind: &ExprKind<'tcx>, depth_lvl: usize) {
+        use rustc_middle::thir::ExprKind::*;
+
+        match expr_kind {
+            Scope { region_scope, value, lint_level } => {
+                print_indented!(self, "Scope {", depth_lvl);
+                print_indented!(self, format!("region_scope: {:?}", region_scope), depth_lvl + 1);
+                print_indented!(self, format!("lint_level: {:?}", lint_level), depth_lvl + 1);
+                print_indented!(self, "value:", depth_lvl + 1);
+                self.print_expr(*value, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Box { value } => {
+                print_indented!(self, "Box {", depth_lvl);
+                self.print_expr(*value, depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            If { if_then_scope, cond, then, else_opt } => {
+                print_indented!(self, "If {", depth_lvl);
+                print_indented!(self, format!("if_then_scope: {:?}", if_then_scope), depth_lvl + 1);
+                print_indented!(self, "cond:", depth_lvl + 1);
+                self.print_expr(*cond, depth_lvl + 2);
+                print_indented!(self, "then:", depth_lvl + 1);
+                self.print_expr(*then, depth_lvl + 2);
+
+                if let Some(else_expr) = else_opt {
+                    print_indented!(self, "else:", depth_lvl + 1);
+                    self.print_expr(*else_expr, depth_lvl + 2);
+                }
+
+                print_indented!(self, "}", depth_lvl);
+            }
+            Call { fun, args, ty, from_hir_call, fn_span } => {
+                print_indented!(self, "Call {", depth_lvl);
+                print_indented!(self, format!("ty: {:?}", ty), depth_lvl + 1);
+                print_indented!(self, format!("from_hir_call: {}", from_hir_call), depth_lvl + 1);
+                print_indented!(self, format!("fn_span: {:?}", fn_span), depth_lvl + 1);
+                print_indented!(self, "fun:", depth_lvl + 1);
+                self.print_expr(*fun, depth_lvl + 2);
+
+                if args.len() > 0 {
+                    print_indented!(self, "args: [", depth_lvl + 1);
+                    for arg in args.iter() {
+                        self.print_expr(*arg, depth_lvl + 2);
+                    }
+                    print_indented!(self, "]", depth_lvl + 1);
+                } else {
+                    print_indented!(self, "args: []", depth_lvl + 1);
+                }
+
+                print_indented!(self, "}", depth_lvl);
+            }
+            Deref { arg } => {
+                print_indented!(self, "Deref {", depth_lvl);
+                self.print_expr(*arg, depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Binary { op, lhs, rhs } => {
+                print_indented!(self, "Binary {", depth_lvl);
+                print_indented!(self, format!("op: {:?}", op), depth_lvl + 1);
+                print_indented!(self, "lhs:", depth_lvl + 1);
+                self.print_expr(*lhs, depth_lvl + 2);
+                print_indented!(self, "rhs:", depth_lvl + 1);
+                self.print_expr(*rhs, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            LogicalOp { op, lhs, rhs } => {
+                print_indented!(self, "LogicalOp {", depth_lvl);
+                print_indented!(self, format!("op: {:?}", op), depth_lvl + 1);
+                print_indented!(self, "lhs:", depth_lvl + 1);
+                self.print_expr(*lhs, depth_lvl + 2);
+                print_indented!(self, "rhs:", depth_lvl + 1);
+                self.print_expr(*rhs, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Unary { op, arg } => {
+                print_indented!(self, "Unary {", depth_lvl);
+                print_indented!(self, format!("op: {:?}", op), depth_lvl + 1);
+                print_indented!(self, "arg:", depth_lvl + 1);
+                self.print_expr(*arg, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Cast { source } => {
+                print_indented!(self, "Cast {", depth_lvl);
+                print_indented!(self, "source:", depth_lvl + 1);
+                self.print_expr(*source, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Use { source } => {
+                print_indented!(self, "Use {", depth_lvl);
+                print_indented!(self, "source:", depth_lvl + 1);
+                self.print_expr(*source, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            NeverToAny { source } => {
+                print_indented!(self, "NeverToAny {", depth_lvl);
+                print_indented!(self, "source:", depth_lvl + 1);
+                self.print_expr(*source, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Pointer { cast, source } => {
+                print_indented!(self, "Pointer {", depth_lvl);
+                print_indented!(self, format!("cast: {:?}", cast), depth_lvl + 1);
+                print_indented!(self, "source:", depth_lvl + 1);
+                self.print_expr(*source, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Loop { body } => {
+                print_indented!(self, "Loop (", depth_lvl);
+                print_indented!(self, "body:", depth_lvl + 1);
+                self.print_expr(*body, depth_lvl + 2);
+                print_indented!(self, ")", depth_lvl);
+            }
+            Let { expr, pat } => {
+                print_indented!(self, "Let {", depth_lvl);
+                print_indented!(self, "expr:", depth_lvl + 1);
+                self.print_expr(*expr, depth_lvl + 2);
+                print_indented!(self, format!("pat: {:?}", pat), depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Match { scrutinee, arms } => {
+                print_indented!(self, "Match {", depth_lvl);
+                print_indented!(self, "scrutinee:", depth_lvl + 1);
+                self.print_expr(*scrutinee, depth_lvl + 2);
+
+                print_indented!(self, "arms: [", depth_lvl + 1);
+                for arm_id in arms.iter() {
+                    self.print_arm(*arm_id, depth_lvl + 2);
+                }
+                print_indented!(self, "]", depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Block { block } => self.print_block(*block, depth_lvl),
+            Assign { lhs, rhs } => {
+                print_indented!(self, "Assign {", depth_lvl);
+                print_indented!(self, "lhs:", depth_lvl + 1);
+                self.print_expr(*lhs, depth_lvl + 2);
+                print_indented!(self, "rhs:", depth_lvl + 1);
+                self.print_expr(*rhs, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            AssignOp { op, lhs, rhs } => {
+                print_indented!(self, "AssignOp {", depth_lvl);
+                print_indented!(self, format!("op: {:?}", op), depth_lvl + 1);
+                print_indented!(self, "lhs:", depth_lvl + 1);
+                self.print_expr(*lhs, depth_lvl + 2);
+                print_indented!(self, "rhs:", depth_lvl + 1);
+                self.print_expr(*rhs, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Field { lhs, variant_index, name } => {
+                print_indented!(self, "Field {", depth_lvl);
+                print_indented!(self, format!("variant_index: {:?}", variant_index), depth_lvl + 1);
+                print_indented!(self, format!("name: {:?}", name), depth_lvl + 1);
+                print_indented!(self, "lhs:", depth_lvl + 1);
+                self.print_expr(*lhs, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Index { lhs, index } => {
+                print_indented!(self, "Index {", depth_lvl);
+                print_indented!(self, format!("index: {:?}", index), depth_lvl + 1);
+                print_indented!(self, "lhs:", depth_lvl + 1);
+                self.print_expr(*lhs, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            VarRef { id } => {
+                print_indented!(self, "VarRef {", depth_lvl);
+                print_indented!(self, format!("id: {:?}", id), depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            UpvarRef { closure_def_id, var_hir_id } => {
+                print_indented!(self, "UpvarRef {", depth_lvl);
+                print_indented!(
+                    self,
+                    format!("closure_def_id: {:?}", closure_def_id),
+                    depth_lvl + 1
+                );
+                print_indented!(self, format!("var_hir_id: {:?}", var_hir_id), depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Borrow { borrow_kind, arg } => {
+                print_indented!(self, "Borrow (", depth_lvl);
+                print_indented!(self, format!("borrow_kind: {:?}", borrow_kind), depth_lvl + 1);
+                print_indented!(self, "arg:", depth_lvl + 1);
+                self.print_expr(*arg, depth_lvl + 2);
+                print_indented!(self, ")", depth_lvl);
+            }
+            AddressOf { mutability, arg } => {
+                print_indented!(self, "AddressOf {", depth_lvl);
+                print_indented!(self, format!("mutability: {:?}", mutability), depth_lvl + 1);
+                print_indented!(self, "arg:", depth_lvl + 1);
+                self.print_expr(*arg, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Break { label, value } => {
+                print_indented!(self, "Break (", depth_lvl);
+                print_indented!(self, format!("label: {:?}", label), depth_lvl + 1);
+
+                if let Some(value) = value {
+                    print_indented!(self, "value:", depth_lvl + 1);
+                    self.print_expr(*value, depth_lvl + 2);
+                }
+
+                print_indented!(self, ")", depth_lvl);
+            }
+            Continue { label } => {
+                print_indented!(self, "Continue {", depth_lvl);
+                print_indented!(self, format!("label: {:?}", label), depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Return { value } => {
+                print_indented!(self, "Return {", depth_lvl);
+                print_indented!(self, "value:", depth_lvl + 1);
+
+                if let Some(value) = value {
+                    self.print_expr(*value, depth_lvl + 2);
+                }
+
+                print_indented!(self, "}", depth_lvl);
+            }
+            ConstBlock { did, substs } => {
+                print_indented!(self, "ConstBlock {", depth_lvl);
+                print_indented!(self, format!("did: {:?}", did), depth_lvl + 1);
+                print_indented!(self, format!("substs: {:?}", substs), depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Repeat { value, count } => {
+                print_indented!(self, "Repeat {", depth_lvl);
+                print_indented!(self, format!("count: {:?}", count), depth_lvl + 1);
+                print_indented!(self, "value:", depth_lvl + 1);
+                self.print_expr(*value, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Array { fields } => {
+                print_indented!(self, "Array {", depth_lvl);
+                print_indented!(self, "fields: [", depth_lvl + 1);
+                for field_id in fields.iter() {
+                    self.print_expr(*field_id, depth_lvl + 2);
+                }
+                print_indented!(self, "]", depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Tuple { fields } => {
+                print_indented!(self, "Tuple {", depth_lvl);
+                print_indented!(self, "fields: [", depth_lvl + 1);
+                for field_id in fields.iter() {
+                    self.print_expr(*field_id, depth_lvl + 2);
+                }
+                print_indented!(self, "]", depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Adt(adt_expr) => {
+                print_indented!(self, "Adt {", depth_lvl);
+                self.print_adt_expr(&**adt_expr, depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            PlaceTypeAscription { source, user_ty } => {
+                print_indented!(self, "PlaceTypeAscription {", depth_lvl);
+                print_indented!(self, format!("user_ty: {:?}", user_ty), depth_lvl + 1);
+                print_indented!(self, "source:", depth_lvl + 1);
+                self.print_expr(*source, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            ValueTypeAscription { source, user_ty } => {
+                print_indented!(self, "ValueTypeAscription {", depth_lvl);
+                print_indented!(self, format!("user_ty: {:?}", user_ty), depth_lvl + 1);
+                print_indented!(self, "source:", depth_lvl + 1);
+                self.print_expr(*source, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Closure(closure_expr) => {
+                print_indented!(self, "Closure {", depth_lvl);
+                print_indented!(self, "closure_expr:", depth_lvl + 1);
+                self.print_closure_expr(&**closure_expr, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Literal { lit, neg } => {
+                print_indented!(
+                    self,
+                    format!("Literal( lit: {:?}, neg: {:?})\n", lit, neg),
+                    depth_lvl
+                );
+            }
+            NonHirLiteral { lit, user_ty } => {
+                print_indented!(self, "NonHirLiteral {", depth_lvl);
+                print_indented!(self, format!("lit: {:?}", lit), depth_lvl + 1);
+                print_indented!(self, format!("user_ty: {:?}", user_ty), depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            ZstLiteral { user_ty } => {
+                print_indented!(self, format!("ZstLiteral(user_ty: {:?})", user_ty), depth_lvl);
+            }
+            NamedConst { def_id, substs, user_ty } => {
+                print_indented!(self, "NamedConst {", depth_lvl);
+                print_indented!(self, format!("def_id: {:?}", def_id), depth_lvl + 1);
+                print_indented!(self, format!("user_ty: {:?}", user_ty), depth_lvl + 1);
+                print_indented!(self, format!("substs: {:?}", substs), depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            ConstParam { param, def_id } => {
+                print_indented!(self, "ConstParam {", depth_lvl);
+                print_indented!(self, format!("def_id: {:?}", def_id), depth_lvl + 1);
+                print_indented!(self, format!("param: {:?}", param), depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            StaticRef { alloc_id, ty, def_id } => {
+                print_indented!(self, "StaticRef {", depth_lvl);
+                print_indented!(self, format!("def_id: {:?}", def_id), depth_lvl + 1);
+                print_indented!(self, format!("ty: {:?}", ty), depth_lvl + 1);
+                print_indented!(self, format!("alloc_id: {:?}", alloc_id), depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            InlineAsm(expr) => {
+                print_indented!(self, "InlineAsm {", depth_lvl);
+                print_indented!(self, "expr:", depth_lvl + 1);
+                self.print_inline_asm_expr(&**expr, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+            ThreadLocalRef(def_id) => {
+                print_indented!(self, "ThreadLocalRef {", depth_lvl);
+                print_indented!(self, format!("def_id: {:?}", def_id), depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl);
+            }
+            Yield { value } => {
+                print_indented!(self, "Yield {", depth_lvl);
+                print_indented!(self, "value:", depth_lvl + 1);
+                self.print_expr(*value, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl);
+            }
+        }
+    }
+
+    fn print_adt_expr(&mut self, adt_expr: &AdtExpr<'tcx>, depth_lvl: usize) {
+        print_indented!(self, "adt_def:", depth_lvl);
+        self.print_adt_def(adt_expr.adt_def, depth_lvl + 1);
+        print_indented!(
+            self,
+            format!("variant_index: {:?}", adt_expr.variant_index),
+            depth_lvl + 1
+        );
+        print_indented!(self, format!("substs: {:?}", adt_expr.substs), depth_lvl + 1);
+        print_indented!(self, format!("user_ty: {:?}", adt_expr.user_ty), depth_lvl + 1);
+
+        for (i, field_expr) in adt_expr.fields.iter().enumerate() {
+            print_indented!(self, format!("field {}:", i), depth_lvl + 1);
+            self.print_expr(field_expr.expr, depth_lvl + 2);
+        }
+
+        if let Some(ref base) = adt_expr.base {
+            print_indented!(self, "base:", depth_lvl + 1);
+            self.print_fru_info(base, depth_lvl + 2);
+        } else {
+            print_indented!(self, "base: None", depth_lvl + 1);
+        }
+    }
+
+    fn print_adt_def(&mut self, adt_def: ty::AdtDef<'tcx>, depth_lvl: usize) {
+        print_indented!(self, "AdtDef {", depth_lvl);
+        print_indented!(self, format!("did: {:?}", adt_def.did()), depth_lvl + 1);
+        print_indented!(self, format!("variants: {:?}", adt_def.variants()), depth_lvl + 1);
+        print_indented!(self, format!("flags: {:?}", adt_def.flags()), depth_lvl + 1);
+        print_indented!(self, format!("repr: {:?}", adt_def.repr()), depth_lvl + 1);
+    }
+
+    fn print_fru_info(&mut self, fru_info: &FruInfo<'tcx>, depth_lvl: usize) {
+        print_indented!(self, "FruInfo {", depth_lvl);
+        print_indented!(self, "base: ", depth_lvl + 1);
+        self.print_expr(fru_info.base, depth_lvl + 2);
+        print_indented!(self, "field_types: [", depth_lvl + 1);
+        for ty in fru_info.field_types.iter() {
+            print_indented!(self, format!("ty: {:?}", ty), depth_lvl + 2);
+        }
+        print_indented!(self, "}", depth_lvl);
+    }
+
+    fn print_arm(&mut self, arm_id: ArmId, depth_lvl: usize) {
+        print_indented!(self, "Arm {", depth_lvl);
+
+        let arm = &self.thir.arms[arm_id];
+        let Arm { pattern, guard, body, lint_level, scope, span } = arm;
+
+        print_indented!(self, "pattern: ", depth_lvl + 1);
+        self.print_pat(pattern, depth_lvl + 2);
+
+        if let Some(guard) = guard {
+            print_indented!(self, "guard: ", depth_lvl + 1);
+            self.print_guard(guard, depth_lvl + 2);
+        } else {
+            print_indented!(self, "guard: None", depth_lvl + 1);
+        }
+
+        print_indented!(self, "body: ", depth_lvl + 1);
+        self.print_expr(*body, depth_lvl + 2);
+        print_indented!(self, format!("lint_level: {:?}", lint_level), depth_lvl + 1);
+        print_indented!(self, format!("scope: {:?}", scope), depth_lvl + 1);
+        print_indented!(self, format!("span: {:?}", span), depth_lvl + 1);
+        print_indented!(self, "}", depth_lvl);
+    }
+
+    fn print_pat(&mut self, pat: &Box<Pat<'tcx>>, depth_lvl: usize) {
+        let Pat { ty, span, kind } = &**pat;
+
+        print_indented!(self, "Pat: {", depth_lvl);
+        print_indented!(self, format!("ty: {:?}", ty), depth_lvl + 1);
+        print_indented!(self, format!("span: {:?}", span), depth_lvl + 1);
+        self.print_pat_kind(kind, depth_lvl + 1);
+        print_indented!(self, "}", depth_lvl);
+    }
+
+    fn print_pat_kind(&mut self, pat_kind: &PatKind<'tcx>, depth_lvl: usize) {
+        print_indented!(self, "kind: PatKind {", depth_lvl);
+
+        match pat_kind {
+            PatKind::Wild => {
+                print_indented!(self, "Wild", depth_lvl + 1);
+            }
+            PatKind::AscribeUserType { ascription, subpattern } => {
+                print_indented!(self, "AscribeUserType: {", depth_lvl + 1);
+                print_indented!(self, format!("ascription: {:?}", ascription), depth_lvl + 2);
+                print_indented!(self, "subpattern: ", depth_lvl + 2);
+                self.print_pat(subpattern, depth_lvl + 3);
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            PatKind::Binding { mutability, name, mode, var, ty, subpattern, is_primary } => {
+                print_indented!(self, "Binding {", depth_lvl + 1);
+                print_indented!(self, format!("mutability: {:?}", mutability), depth_lvl + 2);
+                print_indented!(self, format!("name: {:?}", name), depth_lvl + 2);
+                print_indented!(self, format!("mode: {:?}", mode), depth_lvl + 2);
+                print_indented!(self, format!("var: {:?}", var), depth_lvl + 2);
+                print_indented!(self, format!("ty: {:?}", ty), depth_lvl + 2);
+                print_indented!(self, format!("is_primary: {:?}", is_primary), depth_lvl + 2);
+
+                if let Some(subpattern) = subpattern {
+                    print_indented!(self, "subpattern: Some( ", depth_lvl + 2);
+                    self.print_pat(subpattern, depth_lvl + 3);
+                    print_indented!(self, ")", depth_lvl + 2);
+                } else {
+                    print_indented!(self, "subpattern: None", depth_lvl + 2);
+                }
+
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            PatKind::Variant { adt_def, substs, variant_index, subpatterns } => {
+                print_indented!(self, "Variant {", depth_lvl + 1);
+                print_indented!(self, "adt_def: ", depth_lvl + 2);
+                self.print_adt_def(*adt_def, depth_lvl + 3);
+                print_indented!(self, format!("substs: {:?}", substs), depth_lvl + 2);
+                print_indented!(self, format!("variant_index: {:?}", variant_index), depth_lvl + 2);
+
+                if subpatterns.len() > 0 {
+                    print_indented!(self, "subpatterns: [", depth_lvl + 2);
+                    for field_pat in subpatterns.iter() {
+                        self.print_pat(&field_pat.pattern, depth_lvl + 3);
+                    }
+                    print_indented!(self, "]", depth_lvl + 2);
+                } else {
+                    print_indented!(self, "subpatterns: []", depth_lvl + 2);
+                }
+
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            PatKind::Leaf { subpatterns } => {
+                print_indented!(self, "Leaf { ", depth_lvl + 1);
+                print_indented!(self, "subpatterns: [", depth_lvl + 2);
+                for field_pat in subpatterns.iter() {
+                    self.print_pat(&field_pat.pattern, depth_lvl + 3);
+                }
+                print_indented!(self, "]", depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            PatKind::Deref { subpattern } => {
+                print_indented!(self, "Deref { ", depth_lvl + 1);
+                print_indented!(self, "subpattern: ", depth_lvl + 2);
+                self.print_pat(subpattern, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            PatKind::Constant { value } => {
+                print_indented!(self, "Constant {", depth_lvl + 1);
+                print_indented!(self, format!("value: {:?}", value), depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            PatKind::Range(pat_range) => {
+                print_indented!(self, format!("Range ( {:?} )", pat_range), depth_lvl + 1);
+            }
+            PatKind::Slice { prefix, slice, suffix } => {
+                print_indented!(self, "Slice {", depth_lvl + 1);
+
+                print_indented!(self, "prefix: [", depth_lvl + 2);
+                for prefix_pat in prefix.iter() {
+                    self.print_pat(prefix_pat, depth_lvl + 3);
+                }
+                print_indented!(self, "]", depth_lvl + 2);
+
+                if let Some(slice) = slice {
+                    print_indented!(self, "slice: ", depth_lvl + 2);
+                    self.print_pat(slice, depth_lvl + 3);
+                }
+
+                print_indented!(self, "suffix: [", depth_lvl + 2);
+                for suffix_pat in suffix.iter() {
+                    self.print_pat(suffix_pat, depth_lvl + 3);
+                }
+                print_indented!(self, "]", depth_lvl + 2);
+
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            PatKind::Array { prefix, slice, suffix } => {
+                print_indented!(self, "Array {", depth_lvl + 1);
+
+                print_indented!(self, "prefix: [", depth_lvl + 2);
+                for prefix_pat in prefix.iter() {
+                    self.print_pat(prefix_pat, depth_lvl + 3);
+                }
+                print_indented!(self, "]", depth_lvl + 2);
+
+                if let Some(slice) = slice {
+                    print_indented!(self, "slice: ", depth_lvl + 2);
+                    self.print_pat(slice, depth_lvl + 3);
+                }
+
+                print_indented!(self, "suffix: [", depth_lvl + 2);
+                for suffix_pat in suffix.iter() {
+                    self.print_pat(suffix_pat, depth_lvl + 3);
+                }
+                print_indented!(self, "]", depth_lvl + 2);
+
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            PatKind::Or { pats } => {
+                print_indented!(self, "Or {", depth_lvl + 1);
+                print_indented!(self, "pats: [", depth_lvl + 2);
+                for pat in pats.iter() {
+                    self.print_pat(pat, depth_lvl + 3);
+                }
+                print_indented!(self, "]", depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+        }
+
+        print_indented!(self, "}", depth_lvl);
+    }
+
+    fn print_guard(&mut self, guard: &Guard<'tcx>, depth_lvl: usize) {
+        print_indented!(self, "Guard {", depth_lvl);
+
+        match guard {
+            Guard::If(expr_id) => {
+                print_indented!(self, "If (", depth_lvl + 1);
+                self.print_expr(*expr_id, depth_lvl + 2);
+                print_indented!(self, ")", depth_lvl + 1);
+            }
+            Guard::IfLet(pat, expr_id) => {
+                print_indented!(self, "IfLet (", depth_lvl + 1);
+                self.print_pat(pat, depth_lvl + 2);
+                print_indented!(self, ",", depth_lvl + 1);
+                self.print_expr(*expr_id, depth_lvl + 2);
+                print_indented!(self, ")", depth_lvl + 1);
+            }
+        }
+
+        print_indented!(self, "}", depth_lvl);
+    }
+
+    fn print_closure_expr(&mut self, expr: &ClosureExpr<'tcx>, depth_lvl: usize) {
+        let ClosureExpr { closure_id, substs, upvars, movability, fake_reads } = expr;
+
+        print_indented!(self, "ClosureExpr {", depth_lvl);
+        print_indented!(self, format!("closure_id: {:?}", closure_id), depth_lvl + 1);
+        print_indented!(self, format!("substs: {:?}", substs), depth_lvl + 1);
+
+        if upvars.len() > 0 {
+            print_indented!(self, "upvars: [", depth_lvl + 1);
+            for upvar in upvars.iter() {
+                self.print_expr(*upvar, depth_lvl + 2);
+                print_indented!(self, ",", depth_lvl + 1);
+            }
+            print_indented!(self, "]", depth_lvl + 1);
+        } else {
+            print_indented!(self, "upvars: []", depth_lvl + 1);
+        }
+
+        print_indented!(self, format!("movability: {:?}", movability), depth_lvl + 1);
+
+        if fake_reads.len() > 0 {
+            print_indented!(self, "fake_reads: [", depth_lvl + 1);
+            for (fake_read_expr, cause, hir_id) in fake_reads.iter() {
+                print_indented!(self, "(", depth_lvl + 2);
+                self.print_expr(*fake_read_expr, depth_lvl + 3);
+                print_indented!(self, ",", depth_lvl + 2);
+                print_indented!(self, format!("cause: {:?}", cause), depth_lvl + 3);
+                print_indented!(self, ",", depth_lvl + 2);
+                print_indented!(self, format!("hir_id: {:?}", hir_id), depth_lvl + 3);
+                print_indented!(self, "),", depth_lvl + 2);
+            }
+            print_indented!(self, "]", depth_lvl + 1);
+        } else {
+            print_indented!(self, "fake_reads: []", depth_lvl + 1);
+        }
+
+        print_indented!(self, "}", depth_lvl);
+    }
+
+    fn print_inline_asm_expr(&mut self, expr: &InlineAsmExpr<'tcx>, depth_lvl: usize) {
+        let InlineAsmExpr { template, operands, options, line_spans } = expr;
+
+        print_indented!(self, "InlineAsmExpr {", depth_lvl);
+
+        print_indented!(self, "template: [", depth_lvl + 1);
+        for template_piece in template.iter() {
+            print_indented!(self, format!("{:?}", template_piece), depth_lvl + 2);
+        }
+        print_indented!(self, "]", depth_lvl + 1);
+
+        print_indented!(self, "operands: [", depth_lvl + 1);
+        for operand in operands.iter() {
+            self.print_inline_operand(operand, depth_lvl + 2);
+        }
+        print_indented!(self, "]", depth_lvl + 1);
+
+        print_indented!(self, format!("options: {:?}", options), depth_lvl + 1);
+        print_indented!(self, format!("line_spans: {:?}", line_spans), depth_lvl + 1);
+    }
+
+    fn print_inline_operand(&mut self, operand: &InlineAsmOperand<'tcx>, depth_lvl: usize) {
+        match operand {
+            InlineAsmOperand::In { reg, expr } => {
+                print_indented!(self, "InlineAsmOperand::In {", depth_lvl);
+                print_indented!(self, format!("reg: {:?}", reg), depth_lvl + 1);
+                print_indented!(self, "expr: ", depth_lvl + 1);
+                self.print_expr(*expr, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            InlineAsmOperand::Out { reg, late, expr } => {
+                print_indented!(self, "InlineAsmOperand::Out {", depth_lvl);
+                print_indented!(self, format!("reg: {:?}", reg), depth_lvl + 1);
+                print_indented!(self, format!("late: {:?}", late), depth_lvl + 1);
+
+                if let Some(out) = expr {
+                    print_indented!(self, "place: Some( ", depth_lvl + 1);
+                    self.print_expr(*out, depth_lvl + 2);
+                    print_indented!(self, ")", depth_lvl + 1);
+                } else {
+                    print_indented!(self, "place: None", depth_lvl + 1);
+                }
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            InlineAsmOperand::InOut { reg, late, expr } => {
+                print_indented!(self, "InlineAsmOperand::InOut {", depth_lvl);
+                print_indented!(self, format!("reg: {:?}", reg), depth_lvl + 1);
+                print_indented!(self, format!("late: {:?}", late), depth_lvl + 1);
+                print_indented!(self, "expr: ", depth_lvl + 1);
+                self.print_expr(*expr, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            InlineAsmOperand::SplitInOut { reg, late, in_expr, out_expr } => {
+                print_indented!(self, "InlineAsmOperand::SplitInOut {", depth_lvl);
+                print_indented!(self, format!("reg: {:?}", reg), depth_lvl + 1);
+                print_indented!(self, format!("late: {:?}", late), depth_lvl + 1);
+                print_indented!(self, "in_expr: ", depth_lvl + 1);
+                self.print_expr(*in_expr, depth_lvl + 2);
+
+                if let Some(out_expr) = out_expr {
+                    print_indented!(self, "out_expr: Some( ", depth_lvl + 1);
+                    self.print_expr(*out_expr, depth_lvl + 2);
+                    print_indented!(self, ")", depth_lvl + 1);
+                } else {
+                    print_indented!(self, "out_expr: None", depth_lvl + 1);
+                }
+
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            InlineAsmOperand::Const { value, span } => {
+                print_indented!(self, "InlineAsmOperand::Const {", depth_lvl);
+                print_indented!(self, format!("value: {:?}", value), depth_lvl + 1);
+                print_indented!(self, format!("span: {:?}", span), depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            InlineAsmOperand::SymFn { value, span } => {
+                print_indented!(self, "InlineAsmOperand::SymFn {", depth_lvl);
+                print_indented!(self, format!("value: {:?}", *value), depth_lvl + 1);
+                print_indented!(self, format!("span: {:?}", span), depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+            InlineAsmOperand::SymStatic { def_id } => {
+                print_indented!(self, "InlineAsmOperand::SymStatic {", depth_lvl);
+                print_indented!(self, format!("def_id: {:?}", def_id), depth_lvl + 1);
+                print_indented!(self, "}", depth_lvl + 1);
+            }
+        }
+    }
+}
diff --git a/compiler/rustc_mir_build/src/build/mod.rs b/compiler/rustc_mir_build/src/build/mod.rs
index f85831b4fc6..1655e224ddb 100644
--- a/compiler/rustc_mir_build/src/build/mod.rs
+++ b/compiler/rustc_mir_build/src/build/mod.rs
@@ -439,6 +439,10 @@ fn construct_fn<'tcx>(
     let fn_id = tcx.hir().local_def_id_to_hir_id(fn_def.did);
     let generator_kind = tcx.generator_kind(fn_def.did);
 
+    // The representation of thir for `-Zunpretty=thir-tree` relies on
+    // the entry expression being the last element of `thir.exprs`.
+    assert_eq!(expr.as_usize(), thir.exprs.len() - 1);
+
     // Figure out what primary body this item has.
     let body_id = tcx.hir().body_owned_by(fn_def.did);
     let span_with_body = tcx.hir().span_with_body(fn_id);
diff --git a/compiler/rustc_mir_build/src/lib.rs b/compiler/rustc_mir_build/src/lib.rs
index a428180a4fa..94dae36154c 100644
--- a/compiler/rustc_mir_build/src/lib.rs
+++ b/compiler/rustc_mir_build/src/lib.rs
@@ -34,4 +34,5 @@ pub fn provide(providers: &mut Providers) {
     providers.thir_check_unsafety_for_const_arg = check_unsafety::thir_check_unsafety_for_const_arg;
     providers.thir_body = thir::cx::thir_body;
     providers.thir_tree = thir::cx::thir_tree;
+    providers.thir_flat = thir::cx::thir_flat;
 }
diff --git a/compiler/rustc_mir_build/src/thir/cx/mod.rs b/compiler/rustc_mir_build/src/thir/cx/mod.rs
index a355e1bdab5..10df4b22952 100644
--- a/compiler/rustc_mir_build/src/thir/cx/mod.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/mod.rs
@@ -54,6 +54,16 @@ pub(crate) fn thir_body(
 
 pub(crate) fn thir_tree(tcx: TyCtxt<'_>, owner_def: ty::WithOptConstParam<LocalDefId>) -> String {
     match thir_body(tcx, owner_def) {
+        Ok((thir, _)) => {
+            let thir = thir.steal();
+            tcx.thir_tree_representation(&thir)
+        }
+        Err(_) => "error".into(),
+    }
+}
+
+pub(crate) fn thir_flat(tcx: TyCtxt<'_>, owner_def: ty::WithOptConstParam<LocalDefId>) -> String {
+    match thir_body(tcx, owner_def) {
         Ok((thir, _)) => format!("{:#?}", thir.steal()),
         Err(_) => "error".into(),
     }
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs
index 25de0a9e750..82d9138c7a3 100644
--- a/compiler/rustc_parse/src/parser/ty.rs
+++ b/compiler/rustc_parse/src/parser/ty.rs
@@ -1048,7 +1048,7 @@ impl<'a> Parser<'a> {
                 self.parse_remaining_bounds(bounds, true)?;
                 self.expect(&token::CloseDelim(Delimiter::Parenthesis))?;
                 let sp = vec![lo, self.prev_token.span];
-                let sugg: Vec<_> = sp.iter().map(|sp| (*sp, String::new())).collect();
+                let sugg = vec![(lo, String::from(" ")), (self.prev_token.span, String::new())];
                 self.struct_span_err(sp, "incorrect braces around trait bounds")
                     .multipart_suggestion(
                         "remove the parentheses",
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index db95b8bca2f..c49c5fa9904 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -2573,6 +2573,7 @@ fn parse_pretty(unstable_opts: &UnstableOptions, efmt: ErrorOutputType) -> Optio
         "hir,typed" => Hir(PpHirMode::Typed),
         "hir-tree" => HirTree,
         "thir-tree" => ThirTree,
+        "thir-flat" => ThirFlat,
         "mir" => Mir,
         "mir-cfg" => MirCFG,
         name => early_error(
@@ -2581,7 +2582,8 @@ fn parse_pretty(unstable_opts: &UnstableOptions, efmt: ErrorOutputType) -> Optio
                 "argument to `unpretty` must be one of `normal`, `identified`, \
                             `expanded`, `expanded,identified`, `expanded,hygiene`, \
                             `ast-tree`, `ast-tree,expanded`, `hir`, `hir,identified`, \
-                            `hir,typed`, `hir-tree`, `thir-tree`, `mir` or `mir-cfg`; got {name}"
+                            `hir,typed`, `hir-tree`, `thir-tree`, `thir-flat`, `mir` or \
+                            `mir-cfg`; got {name}"
             ),
         ),
     };
@@ -2736,6 +2738,8 @@ pub enum PpMode {
     HirTree,
     /// `-Zunpretty=thir-tree`
     ThirTree,
+    /// `-Zunpretty=`thir-flat`
+    ThirFlat,
     /// `-Zunpretty=mir`
     Mir,
     /// `-Zunpretty=mir-cfg`
@@ -2754,6 +2758,7 @@ impl PpMode {
             | Hir(_)
             | HirTree
             | ThirTree
+            | ThirFlat
             | Mir
             | MirCFG => true,
         }
@@ -2763,13 +2768,13 @@ impl PpMode {
         match *self {
             Source(_) | AstTree(_) => false,
 
-            Hir(_) | HirTree | ThirTree | Mir | MirCFG => true,
+            Hir(_) | HirTree | ThirTree | ThirFlat | Mir | MirCFG => true,
         }
     }
 
     pub fn needs_analysis(&self) -> bool {
         use PpMode::*;
-        matches!(*self, Mir | MirCFG | ThirTree)
+        matches!(*self, Mir | MirCFG | ThirTree | ThirFlat)
     }
 }