Auto merge of #74582 - Lezzz:rename-hair, r=nikomatsakis

Rename HAIR to THIR (Typed HIR).

r? @nikomatsakis

Originally suggested by @eddyb

36 files changed, 128 insertions, 121 deletions

diff --git a/src/librustc_middle/ty/context.rs b/src/librustc_middle/ty/context.rs
index d307131a990..775d755444d 100644
--- a/src/librustc_middle/ty/context.rs
+++ b/src/librustc_middle/ty/context.rs
@@ -352,7 +352,7 @@ pub struct TypeckResults<'tcx> {
     pat_binding_modes: ItemLocalMap<BindingMode>,
 
     /// Stores the types which were implicitly dereferenced in pattern binding modes
-    /// for later usage in HAIR lowering. For example,
+    /// for later usage in THIR lowering. For example,
     ///
     /// ```
     /// match &&Some(5i32) {
diff --git a/src/librustc_mir_build/build/block.rs b/src/librustc_mir_build/build/block.rs
index 2be4136ad42..d1cbf209b06 100644
--- a/src/librustc_mir_build/build/block.rs
+++ b/src/librustc_mir_build/build/block.rs
@@ -1,7 +1,7 @@
 use crate::build::matches::ArmHasGuard;
 use crate::build::ForGuard::OutsideGuard;
 use crate::build::{BlockAnd, BlockAndExtension, BlockFrame, Builder};
-use crate::hair::*;
+use crate::thir::*;
 use rustc_hir as hir;
 use rustc_middle::mir::*;
 use rustc_session::lint::builtin::UNSAFE_OP_IN_UNSAFE_FN;
@@ -176,7 +176,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             let tail_result_is_ignored =
                 destination_ty.is_unit() || this.block_context.currently_ignores_tail_results();
             let span = match expr {
-                ExprRef::Hair(expr) => expr.span,
+                ExprRef::Thir(expr) => expr.span,
                 ExprRef::Mirror(ref expr) => expr.span,
             };
             this.block_context.push(BlockFrame::TailExpr { tail_result_is_ignored, span });
@@ -235,11 +235,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     .push_unsafe_count
                     .checked_sub(1)
                     .unwrap_or_else(|| span_bug!(span, "unsafe count underflow"));
-                if self.push_unsafe_count == 0 {
-                    Some(self.unpushed_unsafe)
-                } else {
-                    None
-                }
+                if self.push_unsafe_count == 0 { Some(self.unpushed_unsafe) } else { None }
             }
         };
 
diff --git a/src/librustc_mir_build/build/expr/as_constant.rs b/src/librustc_mir_build/build/expr/as_constant.rs
index 03ec0b48f8b..982aefcf604 100644
--- a/src/librustc_mir_build/build/expr/as_constant.rs
+++ b/src/librustc_mir_build/build/expr/as_constant.rs
@@ -1,7 +1,7 @@
 //! See docs in build/expr/mod.rs
 
 use crate::build::Builder;
-use crate::hair::*;
+use crate::thir::*;
 use rustc_middle::mir::*;
 use rustc_middle::ty::CanonicalUserTypeAnnotation;
 
diff --git a/src/librustc_mir_build/build/expr/as_operand.rs b/src/librustc_mir_build/build/expr/as_operand.rs
index 5949fd1e22c..aac93f313f4 100644
--- a/src/librustc_mir_build/build/expr/as_operand.rs
+++ b/src/librustc_mir_build/build/expr/as_operand.rs
@@ -2,7 +2,7 @@
 
 use crate::build::expr::category::Category;
 use crate::build::{BlockAnd, BlockAndExtension, Builder};
-use crate::hair::*;
+use crate::thir::*;
 use rustc_middle::middle::region;
 use rustc_middle::mir::*;
 
diff --git a/src/librustc_mir_build/build/expr/as_place.rs b/src/librustc_mir_build/build/expr/as_place.rs
index e811d68d5a5..1e3e104c2ba 100644
--- a/src/librustc_mir_build/build/expr/as_place.rs
+++ b/src/librustc_mir_build/build/expr/as_place.rs
@@ -3,7 +3,7 @@
 use crate::build::expr::category::Category;
 use crate::build::ForGuard::{OutsideGuard, RefWithinGuard};
 use crate::build::{BlockAnd, BlockAndExtension, Builder};
-use crate::hair::*;
+use crate::thir::*;
 use rustc_middle::middle::region;
 use rustc_middle::mir::AssertKind::BoundsCheck;
 use rustc_middle::mir::*;
diff --git a/src/librustc_mir_build/build/expr/as_rvalue.rs b/src/librustc_mir_build/build/expr/as_rvalue.rs
index e2217fdfac0..9c5fddc6b77 100644
--- a/src/librustc_mir_build/build/expr/as_rvalue.rs
+++ b/src/librustc_mir_build/build/expr/as_rvalue.rs
@@ -4,7 +4,7 @@ use rustc_index::vec::Idx;
 
 use crate::build::expr::category::{Category, RvalueFunc};
 use crate::build::{BlockAnd, BlockAndExtension, Builder};
-use crate::hair::*;
+use crate::thir::*;
 use rustc_middle::middle::region;
 use rustc_middle::mir::AssertKind;
 use rustc_middle::mir::*;
diff --git a/src/librustc_mir_build/build/expr/as_temp.rs b/src/librustc_mir_build/build/expr/as_temp.rs
index 901dadd6612..a9cc0cc2f24 100644
--- a/src/librustc_mir_build/build/expr/as_temp.rs
+++ b/src/librustc_mir_build/build/expr/as_temp.rs
@@ -2,7 +2,7 @@
 
 use crate::build::scope::DropKind;
 use crate::build::{BlockAnd, BlockAndExtension, Builder};
-use crate::hair::*;
+use crate::thir::*;
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_hir as hir;
 use rustc_middle::middle::region;
@@ -67,12 +67,14 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 ExprKind::StaticRef { def_id, .. } => {
                     assert!(!this.hir.tcx().is_thread_local_static(def_id));
                     local_decl.internal = true;
-                    local_decl.local_info = Some(box LocalInfo::StaticRef { def_id, is_thread_local: false });
+                    local_decl.local_info =
+                        Some(box LocalInfo::StaticRef { def_id, is_thread_local: false });
                 }
                 ExprKind::ThreadLocalRef(def_id) => {
                     assert!(this.hir.tcx().is_thread_local_static(def_id));
                     local_decl.internal = true;
-                    local_decl.local_info = Some(box LocalInfo::StaticRef { def_id, is_thread_local: true });
+                    local_decl.local_info =
+                        Some(box LocalInfo::StaticRef { def_id, is_thread_local: true });
                 }
                 _ => {}
             }
diff --git a/src/librustc_mir_build/build/expr/category.rs b/src/librustc_mir_build/build/expr/category.rs
index fb4b7997b6a..9cabd186d84 100644
--- a/src/librustc_mir_build/build/expr/category.rs
+++ b/src/librustc_mir_build/build/expr/category.rs
@@ -1,4 +1,4 @@
-use crate::hair::*;
+use crate::thir::*;
 
 #[derive(Debug, PartialEq)]
 crate enum Category {
diff --git a/src/librustc_mir_build/build/expr/into.rs b/src/librustc_mir_build/build/expr/into.rs
index 36f8034336b..c3f54b39a3f 100644
--- a/src/librustc_mir_build/build/expr/into.rs
+++ b/src/librustc_mir_build/build/expr/into.rs
@@ -2,7 +2,7 @@
 
 use crate::build::expr::category::{Category, RvalueFunc};
 use crate::build::{BlockAnd, BlockAndExtension, BlockFrame, Builder};
-use crate::hair::*;
+use crate::thir::*;
 use rustc_ast::ast::InlineAsmOptions;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stack::ensure_sufficient_stack;
@@ -320,23 +320,23 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 block.unit()
             }
             ExprKind::InlineAsm { template, operands, options, line_spans } => {
-                use crate::hair;
+                use crate::thir;
                 use rustc_middle::mir;
                 let operands = operands
                     .into_iter()
                     .map(|op| match op {
-                        hair::InlineAsmOperand::In { reg, expr } => mir::InlineAsmOperand::In {
+                        thir::InlineAsmOperand::In { reg, expr } => mir::InlineAsmOperand::In {
                             reg,
                             value: unpack!(block = this.as_local_operand(block, expr)),
                         },
-                        hair::InlineAsmOperand::Out { reg, late, expr } => {
+                        thir::InlineAsmOperand::Out { reg, late, expr } => {
                             mir::InlineAsmOperand::Out {
                                 reg,
                                 late,
                                 place: expr.map(|expr| unpack!(block = this.as_place(block, expr))),
                             }
                         }
-                        hair::InlineAsmOperand::InOut { reg, late, expr } => {
+                        thir::InlineAsmOperand::InOut { reg, late, expr } => {
                             let place = unpack!(block = this.as_place(block, expr));
                             mir::InlineAsmOperand::InOut {
                                 reg,
@@ -346,7 +346,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                                 out_place: Some(place),
                             }
                         }
-                        hair::InlineAsmOperand::SplitInOut { reg, late, in_expr, out_expr } => {
+                        thir::InlineAsmOperand::SplitInOut { reg, late, in_expr, out_expr } => {
                             mir::InlineAsmOperand::InOut {
                                 reg,
                                 late,
@@ -356,13 +356,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                                 }),
                             }
                         }
-                        hair::InlineAsmOperand::Const { expr } => mir::InlineAsmOperand::Const {
+                        thir::InlineAsmOperand::Const { expr } => mir::InlineAsmOperand::Const {
                             value: unpack!(block = this.as_local_operand(block, expr)),
                         },
-                        hair::InlineAsmOperand::SymFn { expr } => {
+                        thir::InlineAsmOperand::SymFn { expr } => {
                             mir::InlineAsmOperand::SymFn { value: box this.as_constant(expr) }
                         }
-                        hair::InlineAsmOperand::SymStatic { def_id } => {
+                        thir::InlineAsmOperand::SymStatic { def_id } => {
                             mir::InlineAsmOperand::SymStatic { def_id }
                         }
                     })
diff --git a/src/librustc_mir_build/build/expr/stmt.rs b/src/librustc_mir_build/build/expr/stmt.rs
index 49d6ce39ddf..f117689d940 100644
--- a/src/librustc_mir_build/build/expr/stmt.rs
+++ b/src/librustc_mir_build/build/expr/stmt.rs
@@ -1,11 +1,11 @@
 use crate::build::scope::BreakableTarget;
 use crate::build::{BlockAnd, BlockAndExtension, BlockFrame, Builder};
-use crate::hair::*;
+use crate::thir::*;
 use rustc_middle::middle::region;
 use rustc_middle::mir::*;
 
 impl<'a, 'tcx> Builder<'a, 'tcx> {
-    /// Builds a block of MIR statements to evaluate the HAIR `expr`.
+    /// Builds a block of MIR statements to evaluate the THIR `expr`.
     /// If the original expression was an AST statement,
     /// (e.g., `some().code(&here());`) then `opt_stmt_span` is the
     /// span of that statement (including its semicolon, if any).
@@ -150,8 +150,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                                     break;
                                 }
                             }
-                            this.block_context
-                                .push(BlockFrame::TailExpr { tail_result_is_ignored: true, span: expr.span });
+                            this.block_context.push(BlockFrame::TailExpr {
+                                tail_result_is_ignored: true,
+                                span: expr.span,
+                            });
                             return Some(expr.span);
                         }
                     }
diff --git a/src/librustc_mir_build/build/into.rs b/src/librustc_mir_build/build/into.rs
index 0baa0c833a5..7264e495b84 100644
--- a/src/librustc_mir_build/build/into.rs
+++ b/src/librustc_mir_build/build/into.rs
@@ -5,7 +5,7 @@
 //! latter `EvalInto` trait.
 
 use crate::build::{BlockAnd, Builder};
-use crate::hair::*;
+use crate::thir::*;
 use rustc_middle::mir::*;
 
 pub(in crate::build) trait EvalInto<'tcx> {
diff --git a/src/librustc_mir_build/build/matches/mod.rs b/src/librustc_mir_build/build/matches/mod.rs
index 19948196f25..77c0fe8dda5 100644
--- a/src/librustc_mir_build/build/matches/mod.rs
+++ b/src/librustc_mir_build/build/matches/mod.rs
@@ -9,15 +9,18 @@ use crate::build::scope::DropKind;
 use crate::build::ForGuard::{self, OutsideGuard, RefWithinGuard};
 use crate::build::{BlockAnd, BlockAndExtension, Builder};
 use crate::build::{GuardFrame, GuardFrameLocal, LocalsForNode};
-use crate::hair::{self, *};
-use rustc_data_structures::{fx::{FxHashMap, FxHashSet}, stack::ensure_sufficient_stack};
+use crate::thir::{self, *};
+use rustc_data_structures::{
+    fx::{FxHashMap, FxHashSet},
+    stack::ensure_sufficient_stack,
+};
 use rustc_hir::HirId;
 use rustc_index::bit_set::BitSet;
 use rustc_middle::middle::region;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, CanonicalUserTypeAnnotation, Ty};
-use rustc_span::Span;
 use rustc_span::symbol::Symbol;
+use rustc_span::Span;
 use rustc_target::abi::VariantIdx;
 use smallvec::{smallvec, SmallVec};
 
@@ -395,7 +398,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         ..
                     },
                 ascription:
-                    hair::pattern::Ascription { user_ty: pat_ascription_ty, variance: _, user_ty_span },
+                    thir::pattern::Ascription { user_ty: pat_ascription_ty, variance: _, user_ty_span },
             } => {
                 let place =
                     self.storage_live_binding(block, var, irrefutable_pat.span, OutsideGuard, true);
@@ -631,7 +634,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
             PatKind::AscribeUserType {
                 ref subpattern,
-                ascription: hair::pattern::Ascription { ref user_ty, user_ty_span, variance: _ },
+                ascription: thir::pattern::Ascription { ref user_ty, user_ty_span, variance: _ },
             } => {
                 // This corresponds to something like
                 //
@@ -1982,16 +1985,18 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             source_info,
             internal: false,
             is_block_tail: None,
-            local_info: Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
-                binding_mode,
-                // hypothetically, `visit_primary_bindings` could try to unzip
-                // an outermost hir::Ty as we descend, matching up
-                // idents in pat; but complex w/ unclear UI payoff.
-                // Instead, just abandon providing diagnostic info.
-                opt_ty_info: None,
-                opt_match_place,
-                pat_span,
-            })))),
+            local_info: Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
+                VarBindingForm {
+                    binding_mode,
+                    // hypothetically, `visit_primary_bindings` could try to unzip
+                    // an outermost hir::Ty as we descend, matching up
+                    // idents in pat; but complex w/ unclear UI payoff.
+                    // Instead, just abandon providing diagnostic info.
+                    opt_ty_info: None,
+                    opt_match_place,
+                    pat_span,
+                },
+            )))),
         };
         let for_arm_body = self.local_decls.push(local);
         self.var_debug_info.push(VarDebugInfo {
@@ -2009,7 +2014,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 source_info,
                 internal: false,
                 is_block_tail: None,
-                local_info: Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::RefForGuard))),
+                local_info: Some(box LocalInfo::User(ClearCrossCrate::Set(
+                    BindingForm::RefForGuard,
+                ))),
             });
             self.var_debug_info.push(VarDebugInfo {
                 name,
diff --git a/src/librustc_mir_build/build/matches/simplify.rs b/src/librustc_mir_build/build/matches/simplify.rs
index 2917a771a2c..e584aeb9226 100644
--- a/src/librustc_mir_build/build/matches/simplify.rs
+++ b/src/librustc_mir_build/build/matches/simplify.rs
@@ -14,7 +14,7 @@
 
 use crate::build::matches::{Ascription, Binding, Candidate, MatchPair};
 use crate::build::Builder;
-use crate::hair::{self, *};
+use crate::thir::{self, *};
 use rustc_attr::{SignedInt, UnsignedInt};
 use rustc_hir::RangeEnd;
 use rustc_middle::mir::interpret::truncate;
@@ -108,7 +108,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         match *match_pair.pattern.kind {
             PatKind::AscribeUserType {
                 ref subpattern,
-                ascription: hair::pattern::Ascription { variance, user_ty, user_ty_span },
+                ascription: thir::pattern::Ascription { variance, user_ty, user_ty_span },
             } => {
                 // Apply the type ascription to the value at `match_pair.place`, which is the
                 // value being matched, taking the variance field into account.
diff --git a/src/librustc_mir_build/build/matches/test.rs b/src/librustc_mir_build/build/matches/test.rs
index 3e7bfc7d59b..158ad78a1bf 100644
--- a/src/librustc_mir_build/build/matches/test.rs
+++ b/src/librustc_mir_build/build/matches/test.rs
@@ -7,8 +7,8 @@
 
 use crate::build::matches::{Candidate, MatchPair, Test, TestKind};
 use crate::build::Builder;
-use crate::hair::pattern::compare_const_vals;
-use crate::hair::*;
+use crate::thir::pattern::compare_const_vals;
+use crate::thir::*;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::RangeEnd;
 use rustc_index::bit_set::BitSet;
@@ -443,7 +443,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 destination: Some((eq_result, eq_block)),
                 cleanup: Some(cleanup),
                 from_hir_call: false,
-                fn_span: source_info.span
+                fn_span: source_info.span,
             },
         );
 
diff --git a/src/librustc_mir_build/build/matches/util.rs b/src/librustc_mir_build/build/matches/util.rs
index 7d89a93129b..605396c5eb6 100644
--- a/src/librustc_mir_build/build/matches/util.rs
+++ b/src/librustc_mir_build/build/matches/util.rs
@@ -1,6 +1,6 @@
 use crate::build::matches::MatchPair;
 use crate::build::Builder;
-use crate::hair::*;
+use crate::thir::*;
 use rustc_middle::mir::*;
 use rustc_middle::ty;
 use smallvec::SmallVec;
diff --git a/src/librustc_mir_build/build/mod.rs b/src/librustc_mir_build/build/mod.rs
index 2549b90ddfa..3c4587119cd 100644
--- a/src/librustc_mir_build/build/mod.rs
+++ b/src/librustc_mir_build/build/mod.rs
@@ -1,7 +1,7 @@
 use crate::build;
 use crate::build::scope::DropKind;
-use crate::hair::cx::Cx;
-use crate::hair::{BindingMode, LintLevel, PatKind};
+use crate::thir::cx::Cx;
+use crate::thir::{BindingMode, LintLevel, PatKind};
 use rustc_attr::{self as attr, UnwindAttr};
 use rustc_errors::ErrorReported;
 use rustc_hir as hir;
@@ -294,7 +294,7 @@ struct Builder<'a, 'tcx> {
     /// see the `scope` module for more details.
     scopes: scope::Scopes<'tcx>,
 
-    /// The block-context: each time we build the code within an hair::Block,
+    /// The block-context: each time we build the code within an thir::Block,
     /// we push a frame here tracking whether we are building a statement or
     /// if we are pushing the tail expression of the block. This is used to
     /// embed information in generated temps about whether they were created
diff --git a/src/librustc_mir_build/build/scope.rs b/src/librustc_mir_build/build/scope.rs
index b8df2709447..2a03bb78c6b 100644
--- a/src/librustc_mir_build/build/scope.rs
+++ b/src/librustc_mir_build/build/scope.rs
@@ -1,6 +1,6 @@
 /*!
 Managing the scope stack. The scopes are tied to lexical scopes, so as
-we descend the HAIR, we push a scope on the stack, build its
+we descend the THIR, we push a scope on the stack, build its
 contents, and then pop it off. Every scope is named by a
 `region::Scope`.
 
@@ -83,12 +83,12 @@ should go to.
 */
 
 use crate::build::{BlockAnd, BlockAndExtension, BlockFrame, Builder, CFG};
-use crate::hair::{Expr, ExprRef, LintLevel};
-use rustc_middle::middle::region;
-use rustc_middle::mir::*;
+use crate::thir::{Expr, ExprRef, LintLevel};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir as hir;
 use rustc_hir::GeneratorKind;
+use rustc_middle::middle::region;
+use rustc_middle::mir::*;
 use rustc_span::{Span, DUMMY_SP};
 use std::collections::hash_map::Entry;
 use std::mem;
diff --git a/src/librustc_mir_build/lib.rs b/src/librustc_mir_build/lib.rs
index ed154b9dc6f..30545558933 100644
--- a/src/librustc_mir_build/lib.rs
+++ b/src/librustc_mir_build/lib.rs
@@ -17,13 +17,13 @@ extern crate log;
 extern crate rustc_middle;
 
 mod build;
-mod hair;
 mod lints;
+mod thir;
 
 use rustc_middle::ty::query::Providers;
 
 pub fn provide(providers: &mut Providers) {
-    providers.check_match = hair::pattern::check_match;
-    providers.lit_to_const = hair::constant::lit_to_const;
+    providers.check_match = thir::pattern::check_match;
+    providers.lit_to_const = thir::constant::lit_to_const;
     providers.mir_built = build::mir_built;
 }
diff --git a/src/librustc_mir_build/hair/constant.rs b/src/librustc_mir_build/thir/constant.rs
index e5af0b5bd6b..e5af0b5bd6b 100644
--- a/src/librustc_mir_build/hair/constant.rs
+++ b/src/librustc_mir_build/thir/constant.rs
diff --git a/src/librustc_mir_build/hair/cx/block.rs b/src/librustc_mir_build/thir/cx/block.rs
index a5381781d1d..980888df7fe 100644
--- a/src/librustc_mir_build/hair/cx/block.rs
+++ b/src/librustc_mir_build/thir/cx/block.rs
@@ -1,6 +1,6 @@
-use crate::hair::cx::to_ref::ToRef;
-use crate::hair::cx::Cx;
-use crate::hair::{self, *};
+use crate::thir::cx::to_ref::ToRef;
+use crate::thir::cx::Cx;
+use crate::thir::{self, *};
 
 use rustc_hir as hir;
 use rustc_middle::middle::region;
@@ -71,7 +71,7 @@ fn mirror_stmts<'a, 'tcx>(
                             ty: pattern.ty,
                             span: pattern.span,
                             kind: Box::new(PatKind::AscribeUserType {
-                                ascription: hair::pattern::Ascription {
+                                ascription: thir::pattern::Ascription {
                                     user_ty: PatTyProj::from_user_type(user_ty),
                                     user_ty_span: ty.span,
                                     variance: ty::Variance::Covariant,
diff --git a/src/librustc_mir_build/hair/cx/expr.rs b/src/librustc_mir_build/thir/cx/expr.rs
index 6e1d8a8fc40..ea41a66b3e4 100644
--- a/src/librustc_mir_build/hair/cx/expr.rs
+++ b/src/librustc_mir_build/thir/cx/expr.rs
@@ -1,8 +1,8 @@
-use crate::hair::cx::block;
-use crate::hair::cx::to_ref::ToRef;
-use crate::hair::cx::Cx;
-use crate::hair::util::UserAnnotatedTyHelpers;
-use crate::hair::*;
+use crate::thir::cx::block;
+use crate::thir::cx::to_ref::ToRef;
+use crate::thir::cx::Cx;
+use crate::thir::util::UserAnnotatedTyHelpers;
+use crate::thir::*;
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
 use rustc_index::vec::Idx;
@@ -1020,7 +1020,7 @@ fn overloaded_place<'a, 'tcx>(
     // line up (this is because `*x` and `x[y]` represent places):
 
     let recv_ty = match args[0] {
-        ExprRef::Hair(e) => cx.typeck_results().expr_ty_adjusted(e),
+        ExprRef::Thir(e) => cx.typeck_results().expr_ty_adjusted(e),
         ExprRef::Mirror(ref e) => e.ty,
     };
 
diff --git a/src/librustc_mir_build/hair/cx/mod.rs b/src/librustc_mir_build/thir/cx/mod.rs
index 2694cde14fd..21736df7b07 100644
--- a/src/librustc_mir_build/hair/cx/mod.rs
+++ b/src/librustc_mir_build/thir/cx/mod.rs
@@ -1,9 +1,9 @@
 //! This module contains the functionality to convert from the wacky tcx data
-//! structures into the HAIR. The `builder` is generally ignorant of the tcx,
+//! structures into the THIR. The `builder` is generally ignorant of the tcx,
 //! etc., and instead goes through the `Cx` for most of its work.
 
-use crate::hair::util::UserAnnotatedTyHelpers;
-use crate::hair::*;
+use crate::thir::util::UserAnnotatedTyHelpers;
+use crate::thir::*;
 
 use rustc_ast::ast;
 use rustc_ast::attr;
diff --git a/src/librustc_mir_build/hair/cx/to_ref.rs b/src/librustc_mir_build/thir/cx/to_ref.rs
index 6cf8122e200..53a988ebb79 100644
--- a/src/librustc_mir_build/hair/cx/to_ref.rs
+++ b/src/librustc_mir_build/thir/cx/to_ref.rs
@@ -1,4 +1,4 @@
-use crate::hair::*;
+use crate::thir::*;
 
 use rustc_hir as hir;
 
@@ -11,7 +11,7 @@ impl<'tcx> ToRef for &'tcx hir::Expr<'tcx> {
     type Output = ExprRef<'tcx>;
 
     fn to_ref(self) -> ExprRef<'tcx> {
-        ExprRef::Hair(self)
+        ExprRef::Thir(self)
     }
 }
 
@@ -19,7 +19,7 @@ impl<'tcx> ToRef for &'tcx &'tcx hir::Expr<'tcx> {
     type Output = ExprRef<'tcx>;
 
     fn to_ref(self) -> ExprRef<'tcx> {
-        ExprRef::Hair(&**self)
+        ExprRef::Thir(&**self)
     }
 }
 
diff --git a/src/librustc_mir_build/hair/mod.rs b/src/librustc_mir_build/thir/mod.rs
index ccff510f2d4..b6ce7e0b41e 100644
--- a/src/librustc_mir_build/hair/mod.rs
+++ b/src/librustc_mir_build/thir/mod.rs
@@ -1,5 +1,5 @@
-//! The MIR is built from some high-level abstract IR
-//! (HAIR). This section defines the HAIR along with a trait for
+//! The MIR is built from some typed high-level IR
+//! (THIR). This section defines the THIR along with a trait for
 //! accessing it. The intention is to allow MIR construction to be
 //! unit-tested and separated from the Rust source and compiler data
 //! structures.
@@ -99,18 +99,18 @@ crate enum StmtKind<'tcx> {
 #[cfg(target_arch = "x86_64")]
 rustc_data_structures::static_assert_size!(Expr<'_>, 168);
 
-/// The Hair trait implementor lowers their expressions (`&'tcx H::Expr`)
+/// The Thir trait implementor lowers their expressions (`&'tcx H::Expr`)
 /// into instances of this `Expr` enum. This lowering can be done
 /// basically as lazily or as eagerly as desired: every recursive
 /// reference to an expression in this enum is an `ExprRef<'tcx>`, which
 /// may in turn be another instance of this enum (boxed), or else an
 /// unlowered `&'tcx H::Expr`. Note that instances of `Expr` are very
-/// short-lived. They are created by `Hair::to_expr`, analyzed and
+/// short-lived. They are created by `Thir::to_expr`, analyzed and
 /// converted into MIR, and then discarded.
 ///
 /// If you compare `Expr` to the full compiler AST, you will see it is
 /// a good bit simpler. In fact, a number of the more straight-forward
-/// MIR simplifications are already done in the impl of `Hair`. For
+/// MIR simplifications are already done in the impl of `Thir`. For
 /// example, method calls and overloaded operators are absent: they are
 /// expected to be converted into `Expr::Call` instances.
 #[derive(Clone, Debug)]
@@ -302,7 +302,7 @@ crate enum ExprKind<'tcx> {
 
 #[derive(Clone, Debug)]
 crate enum ExprRef<'tcx> {
-    Hair(&'tcx hir::Expr<'tcx>),
+    Thir(&'tcx hir::Expr<'tcx>),
     Mirror(Box<Expr<'tcx>>),
 }
 
@@ -342,7 +342,7 @@ crate enum LogicalOp {
 impl<'tcx> ExprRef<'tcx> {
     crate fn span(&self) -> Span {
         match self {
-            ExprRef::Hair(expr) => expr.span,
+            ExprRef::Thir(expr) => expr.span,
             ExprRef::Mirror(expr) => expr.span,
         }
     }
@@ -385,7 +385,7 @@ crate enum InlineAsmOperand<'tcx> {
 // The Mirror trait
 
 /// "Mirroring" is the process of converting from a HIR type into one
-/// of the HAIR types defined in this file. This is basically a "on
+/// of the THIR types defined in this file. This is basically a "on
 /// the fly" desugaring step that hides a lot of the messiness in the
 /// tcx. For example, the mirror of a `&'tcx hir::Expr` is an
 /// `Expr<'tcx>`.
@@ -394,7 +394,7 @@ crate enum InlineAsmOperand<'tcx> {
 /// + e2`, the references to the inner expressions `e1` and `e2` are
 /// `ExprRef<'tcx>` instances, and they may or may not be eagerly
 /// mirrored. This allows a single AST node from the compiler to
-/// expand into one or more Hair nodes, which lets the Hair nodes be
+/// expand into one or more Thir nodes, which lets the Thir nodes be
 /// simpler.
 crate trait Mirror<'tcx> {
     type Output;
@@ -415,7 +415,7 @@ impl<'tcx> Mirror<'tcx> for ExprRef<'tcx> {
 
     fn make_mirror(self, hir: &mut Cx<'_, 'tcx>) -> Expr<'tcx> {
         match self {
-            ExprRef::Hair(h) => h.make_mirror(hir),
+            ExprRef::Thir(h) => h.make_mirror(hir),
             ExprRef::Mirror(m) => *m,
         }
     }
diff --git a/src/librustc_mir_build/hair/pattern/_match.rs b/src/librustc_mir_build/thir/pattern/_match.rs
index 3202f7d1b1b..3202f7d1b1b 100644
--- a/src/librustc_mir_build/hair/pattern/_match.rs
+++ b/src/librustc_mir_build/thir/pattern/_match.rs
diff --git a/src/librustc_mir_build/hair/pattern/check_match.rs b/src/librustc_mir_build/thir/pattern/check_match.rs
index 744f319205f..744f319205f 100644
--- a/src/librustc_mir_build/hair/pattern/check_match.rs
+++ b/src/librustc_mir_build/thir/pattern/check_match.rs
diff --git a/src/librustc_mir_build/hair/pattern/const_to_pat.rs b/src/librustc_mir_build/thir/pattern/const_to_pat.rs
index 6dd7e0871b4..6dd7e0871b4 100644
--- a/src/librustc_mir_build/hair/pattern/const_to_pat.rs
+++ b/src/librustc_mir_build/thir/pattern/const_to_pat.rs
diff --git a/src/librustc_mir_build/hair/pattern/mod.rs b/src/librustc_mir_build/thir/pattern/mod.rs
index 19c86655bd5..bdefaadfdfe 100644
--- a/src/librustc_mir_build/hair/pattern/mod.rs
+++ b/src/librustc_mir_build/thir/pattern/mod.rs
@@ -6,7 +6,7 @@ mod const_to_pat;
 
 pub(crate) use self::check_match::check_match;
 
-use crate::hair::util::UserAnnotatedTyHelpers;
+use crate::thir::util::UserAnnotatedTyHelpers;
 
 use rustc_ast::ast;
 use rustc_errors::struct_span_err;
@@ -402,7 +402,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         //
         // `vec![&&Option<i32>, &Option<i32>]`.
         //
-        // Applying the adjustments, we want to instead output `&&Some(n)` (as a HAIR pattern). So
+        // Applying the adjustments, we want to instead output `&&Some(n)` (as a THIR pattern). So
         // we wrap the unadjusted pattern in `PatKind::Deref` repeatedly, consuming the
         // adjustments in *reverse order* (last-in-first-out, so that the last `Deref` inserted
         // gets the least-dereferenced type).
diff --git a/src/librustc_mir_build/hair/util.rs b/src/librustc_mir_build/thir/util.rs
index 7de60ddda41..7de60ddda41 100644
--- a/src/librustc_mir_build/hair/util.rs
+++ b/src/librustc_mir_build/thir/util.rs
diff --git a/src/librustc_typeck/check/pat.rs b/src/librustc_typeck/check/pat.rs
index 42170bc199c..9c7ea34bf51 100644
--- a/src/librustc_typeck/check/pat.rs
+++ b/src/librustc_typeck/check/pat.rs
@@ -345,7 +345,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             debug!("inspecting {:?}", expected);
 
             debug!("current discriminant is Ref, inserting implicit deref");
-            // Preserve the reference type. We'll need it later during HAIR lowering.
+            // Preserve the reference type. We'll need it later during THIR lowering.
             pat_adjustments.push(expected);
 
             expected = inner_ty;
diff --git a/src/test/ui/consts/const_constructor/const-construct-call.rs b/src/test/ui/consts/const_constructor/const-construct-call.rs
index d883d3fa6e4..d3e6cf78bc9 100644
--- a/src/test/ui/consts/const_constructor/const-construct-call.rs
+++ b/src/test/ui/consts/const_constructor/const-construct-call.rs
@@ -6,7 +6,7 @@
 
 #![cfg_attr(const_fn, feature(const_fn))]
 
-// Ctor(..) is transformed to Ctor { 0: ... } in HAIR lowering, so directly
+// Ctor(..) is transformed to Ctor { 0: ... } in THIR lowering, so directly
 // calling constructors doesn't require them to be const.
 
 type ExternalType = std::panic::AssertUnwindSafe<(Option<i32>, Result<i32, bool>)>;
diff --git a/src/test/ui/half-open-range-patterns/half-open-range-pats-hair-lower-empty.rs b/src/test/ui/half-open-range-patterns/half-open-range-pats-thir-lower-empty.rs
index 904efda903c..904efda903c 100644
--- a/src/test/ui/half-open-range-patterns/half-open-range-pats-hair-lower-empty.rs
+++ b/src/test/ui/half-open-range-patterns/half-open-range-pats-thir-lower-empty.rs
diff --git a/src/test/ui/half-open-range-patterns/half-open-range-pats-hair-lower-empty.stderr b/src/test/ui/half-open-range-patterns/half-open-range-pats-thir-lower-empty.stderr
index b536e1b5548..12ad8642961 100644
--- a/src/test/ui/half-open-range-patterns/half-open-range-pats-hair-lower-empty.stderr
+++ b/src/test/ui/half-open-range-patterns/half-open-range-pats-thir-lower-empty.stderr
@@ -1,155 +1,155 @@
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:12:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:12:11
    |
 LL |     m!(0, ..core::u8::MIN);
    |           ^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:15:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:15:11
    |
 LL |     m!(0, ..core::u16::MIN);
    |           ^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:18:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:18:11
    |
 LL |     m!(0, ..core::u32::MIN);
    |           ^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:21:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:21:11
    |
 LL |     m!(0, ..core::u64::MIN);
    |           ^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:24:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:24:11
    |
 LL |     m!(0, ..core::u128::MIN);
    |           ^^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:28:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:28:11
    |
 LL |     m!(0, ..core::i8::MIN);
    |           ^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:31:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:31:11
    |
 LL |     m!(0, ..core::i16::MIN);
    |           ^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:34:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:34:11
    |
 LL |     m!(0, ..core::i32::MIN);
    |           ^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:37:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:37:11
    |
 LL |     m!(0, ..core::i64::MIN);
    |           ^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:40:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:40:11
    |
 LL |     m!(0, ..core::i128::MIN);
    |           ^^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:44:14
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:44:14
    |
 LL |     m!(0f32, ..core::f32::NEG_INFINITY);
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:47:14
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:47:14
    |
 LL |     m!(0f64, ..core::f64::NEG_INFINITY);
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:51:13
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:51:13
    |
 LL |     m!('a', ..'\u{0}');
    |             ^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:12:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:12:11
    |
 LL |     m!(0, ..core::u8::MIN);
    |           ^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:15:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:15:11
    |
 LL |     m!(0, ..core::u16::MIN);
    |           ^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:18:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:18:11
    |
 LL |     m!(0, ..core::u32::MIN);
    |           ^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:21:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:21:11
    |
 LL |     m!(0, ..core::u64::MIN);
    |           ^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:24:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:24:11
    |
 LL |     m!(0, ..core::u128::MIN);
    |           ^^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:28:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:28:11
    |
 LL |     m!(0, ..core::i8::MIN);
    |           ^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:31:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:31:11
    |
 LL |     m!(0, ..core::i16::MIN);
    |           ^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:34:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:34:11
    |
 LL |     m!(0, ..core::i32::MIN);
    |           ^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:37:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:37:11
    |
 LL |     m!(0, ..core::i64::MIN);
    |           ^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:40:11
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:40:11
    |
 LL |     m!(0, ..core::i128::MIN);
    |           ^^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:44:14
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:44:14
    |
 LL |     m!(0f32, ..core::f32::NEG_INFINITY);
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:47:14
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:47:14
    |
 LL |     m!(0f64, ..core::f64::NEG_INFINITY);
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0579]: lower range bound must be less than upper
-  --> $DIR/half-open-range-pats-hair-lower-empty.rs:51:13
+  --> $DIR/half-open-range-pats-thir-lower-empty.rs:51:13
    |
 LL |     m!('a', ..'\u{0}');
    |             ^^^^^^^^^
diff --git a/src/test/ui/pattern/bindings-after-at/borrowck-pat-by-move-and-ref-inverse-promotion.rs b/src/test/ui/pattern/bindings-after-at/borrowck-pat-by-move-and-ref-inverse-promotion.rs
index 14797917193..993954b450e 100644
--- a/src/test/ui/pattern/bindings-after-at/borrowck-pat-by-move-and-ref-inverse-promotion.rs
+++ b/src/test/ui/pattern/bindings-after-at/borrowck-pat-by-move-and-ref-inverse-promotion.rs
@@ -1,5 +1,5 @@
 // Test that `by_move_binding @ pat_with_by_ref_bindings` is prevented even with promotion.
-// Currently this logic exists in HAIR match checking as opposed to borrowck.
+// Currently this logic exists in THIR match checking as opposed to borrowck.
 
 #![feature(bindings_after_at)]
 #![feature(move_ref_pattern)]
diff --git a/src/test/ui/pattern/const-pat-ice.stderr b/src/test/ui/pattern/const-pat-ice.stderr
index 6e87e5c6912..2aa0824f301 100644
--- a/src/test/ui/pattern/const-pat-ice.stderr
+++ b/src/test/ui/pattern/const-pat-ice.stderr
@@ -1,4 +1,4 @@
-thread 'rustc' panicked at 'assertion failed: rows.iter().all(|r| r.len() == v.len())', src/librustc_mir_build/hair/pattern/_match.rs:LL:CC
+thread 'rustc' panicked at 'assertion failed: rows.iter().all(|r| r.len() == v.len())', src/librustc_mir_build/thir/pattern/_match.rs:LL:CC
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 
 error: internal compiler error: unexpected panic
diff --git a/src/tools/clippy/clippy_lints/src/utils/mod.rs b/src/tools/clippy/clippy_lints/src/utils/mod.rs
index 655b1133cf7..3f8e15d9029 100644
--- a/src/tools/clippy/clippy_lints/src/utils/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/mod.rs
@@ -883,7 +883,7 @@ pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_
 }
 
 /// Returns `true` if a pattern is refutable.
-// TODO: should be implemented using rustc/mir_build/hair machinery
+// TODO: should be implemented using rustc/mir_build/thir machinery
 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
     fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
         matches!(