Record for each MIR local where it has been introduced.

cjgillot · cjgillot · commit fcdf963f2bff · 2025-10-04T16:35:13.000Z
diff --git a/compiler/rustc_borrowck/src/diagnostics/move_errors.rs b/compiler/rustc_borrowck/src/diagnostics/move_errors.rs
@@ -139,9 +139,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             // whether or not the right-hand side is a place expression
             if let LocalInfo::User(BindingForm::Var(VarBindingForm {
                 opt_match_place: Some((opt_match_place, match_span)),
-                binding_mode: _,
-                opt_ty_info: _,
-                pat_span: _,
+                ..
             })) = *local_decl.local_info()
             {
                 let stmt_source_info = self.body.source_info(location);
diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -335,8 +335,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                         LocalInfo::User(BindingForm::Var(mir::VarBindingForm {
                             binding_mode: BindingMode(ByRef::No, Mutability::Not),
                             opt_ty_info: Some(sp),
-                            opt_match_place: _,
-                            pat_span: _,
+                            ..
                         })) => {
                             if suggest {
                                 err.span_note(sp, "the binding is already a mutable borrow");
@@ -750,6 +749,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 opt_ty_info: _,
                 opt_match_place: _,
                 pat_span,
+                introductions: _,
             })) => pat_span,
             _ => local_decl.source_info.span,
         };
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
@@ -882,6 +882,8 @@ pub struct VarBindingForm<'tcx> {
     pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
     /// The span of the pattern in which this variable was bound.
     pub pat_span: Span,
+    /// For each introduction place, record here the span and whether this was a shorthand pattern.
+    pub introductions: Vec<(Span, /* is_shorthand */ bool)>,
 }
 
 #[derive(Clone, Debug, TyEncodable, TyDecodable)]
@@ -1088,12 +1090,8 @@ impl<'tcx> LocalDecl<'tcx> {
         matches!(
             self.local_info(),
             LocalInfo::User(
-                BindingForm::Var(VarBindingForm {
-                    binding_mode: BindingMode(ByRef::No, _),
-                    opt_ty_info: _,
-                    opt_match_place: _,
-                    pat_span: _,
-                }) | BindingForm::ImplicitSelf(ImplicitSelfKind::Imm),
+                BindingForm::Var(VarBindingForm { binding_mode: BindingMode(ByRef::No, _), .. })
+                    | BindingForm::ImplicitSelf(ImplicitSelfKind::Imm),
             )
         )
     }
@@ -1105,12 +1103,8 @@ impl<'tcx> LocalDecl<'tcx> {
         matches!(
             self.local_info(),
             LocalInfo::User(
-                BindingForm::Var(VarBindingForm {
-                    binding_mode: BindingMode(ByRef::No, _),
-                    opt_ty_info: _,
-                    opt_match_place: _,
-                    pat_span: _,
-                }) | BindingForm::ImplicitSelf(_),
+                BindingForm::Var(VarBindingForm { binding_mode: BindingMode(ByRef::No, _), .. })
+                    | BindingForm::ImplicitSelf(_),
             )
         )
     }
diff --git a/compiler/rustc_middle/src/thir.rs b/compiler/rustc_middle/src/thir.rs
@@ -798,6 +798,7 @@ pub enum PatKind<'tcx> {
         /// (The same binding can occur multiple times in different branches of
         /// an or-pattern, but only one of them will be primary.)
         is_primary: bool,
+        is_shorthand: bool,
     },
 
     /// `Foo(...)` or `Foo{...}` or `Foo`, where `Foo` is a variant name from an ADT with
diff --git a/compiler/rustc_mir_build/src/builder/block.rs b/compiler/rustc_mir_build/src/builder/block.rs
@@ -286,6 +286,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                                 block,
                                 node,
                                 span,
+                                false,
                                 OutsideGuard,
                                 ScheduleDrops::Yes,
                             );
diff --git a/compiler/rustc_mir_build/src/builder/matches/match_pair.rs b/compiler/rustc_mir_build/src/builder/matches/match_pair.rs
@@ -170,7 +170,7 @@ impl<'tcx> MatchPairTree<'tcx> {
                 None
             }
 
-            PatKind::Binding { mode, var, ref subpattern, .. } => {
+            PatKind::Binding { mode, var, is_shorthand, ref subpattern, .. } => {
                 // In order to please the borrow checker, when lowering a pattern
                 // like `x @ subpat` we must establish any bindings in `subpat`
                 // before establishing the binding for `x`.
@@ -209,6 +209,7 @@ impl<'tcx> MatchPairTree<'tcx> {
                         source,
                         var_id: var,
                         binding_mode: mode,
+                        is_shorthand,
                     }));
                 }
 
diff --git a/compiler/rustc_mir_build/src/builder/matches/mod.rs b/compiler/rustc_mir_build/src/builder/matches/mod.rs
@@ -579,6 +579,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     block,
                     var,
                     irrefutable_pat.span,
+                    false,
                     OutsideGuard,
                     ScheduleDrops::Yes,
                 );
@@ -608,6 +609,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     block,
                     var,
                     irrefutable_pat.span,
+                    false,
                     OutsideGuard,
                     ScheduleDrops::Yes,
                 );
@@ -799,6 +801,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         block: BasicBlock,
         var: LocalVarId,
         span: Span,
+        is_shorthand: bool,
         for_guard: ForGuard,
         schedule_drop: ScheduleDrops,
     ) -> Place<'tcx> {
@@ -812,6 +815,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         {
             self.schedule_drop(span, region_scope, local_id, DropKind::Storage);
         }
+        let local_info = self.local_decls[local_id].local_info.as_mut().unwrap_crate_local();
+        if let LocalInfo::User(BindingForm::Var(var_info)) = &mut **local_info {
+            var_info.introductions.push((span, is_shorthand));
+        }
         Place::from(local_id)
     }
 
@@ -1217,6 +1224,7 @@ struct Binding<'tcx> {
     source: Place<'tcx>,
     var_id: LocalVarId,
     binding_mode: BindingMode,
+    is_shorthand: bool,
 }
 
 /// Indicates that the type of `source` must be a subtype of the
@@ -2725,6 +2733,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 block,
                 binding.var_id,
                 binding.span,
+                binding.is_shorthand,
                 RefWithinGuard,
                 ScheduleDrops::Yes,
             );
@@ -2742,6 +2751,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         block,
                         binding.var_id,
                         binding.span,
+                        binding.is_shorthand,
                         OutsideGuard,
                         ScheduleDrops::Yes,
                     );
@@ -2775,6 +2785,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 block,
                 binding.var_id,
                 binding.span,
+                binding.is_shorthand,
                 OutsideGuard,
                 schedule_drops,
             );
@@ -2827,6 +2838,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     opt_ty_info: None,
                     opt_match_place,
                     pat_span,
+                    introductions: Vec::new(),
                 },
             )))),
         };
diff --git a/compiler/rustc_mir_build/src/builder/mod.rs b/compiler/rustc_mir_build/src/builder/mod.rs
@@ -1054,6 +1054,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                                 opt_ty_info: param.ty_span,
                                 opt_match_place: Some((None, span)),
                                 pat_span: span,
+                                introductions: vec![(span, false)],
                             }))
                         };
                     self.var_indices.insert(var, LocalsForNode::One(local));
diff --git a/compiler/rustc_mir_build/src/thir/pattern/mod.rs b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
@@ -369,6 +369,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
                     ty: var_ty,
                     subpattern: self.lower_opt_pattern(sub),
                     is_primary: id == pat.hir_id,
+                    is_shorthand: false,
                 }
             }
 
@@ -386,9 +387,13 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
                 let res = self.typeck_results.qpath_res(qpath, pat.hir_id);
                 let subpatterns = fields
                     .iter()
-                    .map(|field| FieldPat {
-                        field: self.typeck_results.field_index(field.hir_id),
-                        pattern: *self.lower_pattern(field.pat),
+                    .map(|field| {
+                        let mut pattern = *self.lower_pattern(field.pat);
+                        if let PatKind::Binding { ref mut is_shorthand, .. } = pattern.kind {
+                            *is_shorthand = field.is_shorthand;
+                        }
+                        let field = self.typeck_results.field_index(field.hir_id);
+                        FieldPat { field, pattern }
                     })
                     .collect();
 
diff --git a/compiler/rustc_mir_build/src/thir/print.rs b/compiler/rustc_mir_build/src/thir/print.rs
@@ -703,13 +703,14 @@ impl<'a, 'tcx> ThirPrinter<'a, 'tcx> {
                 self.print_pat(subpattern, depth_lvl + 3);
                 print_indented!(self, "}", depth_lvl + 1);
             }
-            PatKind::Binding { name, mode, var, ty, subpattern, is_primary } => {
+            PatKind::Binding { name, mode, var, ty, subpattern, is_primary, is_shorthand } => {
                 print_indented!(self, "Binding {", depth_lvl + 1);
                 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);
+                print_indented!(self, format!("is_shorthand: {:?}", is_shorthand), depth_lvl + 2);
 
                 if let Some(subpattern) = subpattern {
                     print_indented!(self, "subpattern: Some( ", depth_lvl + 2);
diff --git a/tests/ui/thir-print/thir-tree-loop-match.stdout b/tests/ui/thir-print/thir-tree-loop-match.stdout
@@ -16,6 +16,7 @@ params: [
                         var: LocalVarId(HirId(DefId(0:3 ~ thir_tree_loop_match[3c53]::boolean).2))
                         ty: bool
                         is_primary: true
+                        is_shorthand: false
                         subpattern: None
                     }
                 }
diff --git a/tests/ui/thir-print/thir-tree-match.stdout b/tests/ui/thir-print/thir-tree-match.stdout
@@ -16,6 +16,7 @@ params: [
                         var: LocalVarId(HirId(DefId(0:16 ~ thir_tree_match[fcf8]::has_match).2))
                         ty: Foo
                         is_primary: true
+                        is_shorthand: false
                         subpattern: None
                     }
                 }

Original file line number	Diff line number	Diff line change
`@@ -882,6 +882,8 @@ pub struct VarBindingForm<'tcx> {`
`882`	`882`	`pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,`
`883`	`883`	`/// The span of the pattern in which this variable was bound.`
`884`	`884`	`pub pat_span: Span,`
	`885`	`+ /// For each introduction place, record here the span and whether this was a shorthand pattern.`
	`886`	`+ pub introductions: Vec<(Span, /* is_shorthand */ bool)>,`
`885`	`887`	`}`
`886`	`888`
`887`	`889`	`#[derive(Clone, Debug, TyEncodable, TyDecodable)]`
`@@ -1088,12 +1090,8 @@ impl<'tcx> LocalDecl<'tcx> {`
`1088`	`1090`	`matches!(`
`1089`	`1091`	`self.local_info(),`
`1090`	`1092`	`LocalInfo::User(`
`1091`		`- BindingForm::Var(VarBindingForm {`
`1092`		`- binding_mode: BindingMode(ByRef::No, _),`
`1093`		`- opt_ty_info: _,`
`1094`		`- opt_match_place: _,`
`1095`		`- pat_span: _,`
`1096`		`- }) \| BindingForm::ImplicitSelf(ImplicitSelfKind::Imm),`
	`1093`	`+ BindingForm::Var(VarBindingForm { binding_mode: BindingMode(ByRef::No, _), .. })`
	`1094`	`+ \| BindingForm::ImplicitSelf(ImplicitSelfKind::Imm),`
`1097`	`1095`	`)`
`1098`	`1096`	`)`
`1099`	`1097`	`}`
`@@ -1105,12 +1103,8 @@ impl<'tcx> LocalDecl<'tcx> {`
`1105`	`1103`	`matches!(`
`1106`	`1104`	`self.local_info(),`
`1107`	`1105`	`LocalInfo::User(`
`1108`		`- BindingForm::Var(VarBindingForm {`
`1109`		`- binding_mode: BindingMode(ByRef::No, _),`
`1110`		`- opt_ty_info: _,`
`1111`		`- opt_match_place: _,`
`1112`		`- pat_span: _,`
`1113`		`- }) \| BindingForm::ImplicitSelf(_),`
	`1106`	`+ BindingForm::Var(VarBindingForm { binding_mode: BindingMode(ByRef::No, _), .. })`
	`1107`	`+ \| BindingForm::ImplicitSelf(_),`
`1114`	`1108`	`)`
`1115`	`1109`	`)`
`1116`	`1110`	`}`
Original file line number	Diff line number	Diff line change
`@@ -170,7 +170,7 @@ impl<'tcx> MatchPairTree<'tcx> {`
`170`	`170`	`None`
`171`	`171`	`}`
`172`	`172`
`173`		`- PatKind::Binding { mode, var, ref subpattern, .. } => {`
	`173`	`+ PatKind::Binding { mode, var, is_shorthand, ref subpattern, .. } => {`
`174`	`174`	`// In order to please the borrow checker, when lowering a pattern`
`175`	`175`	// like `x @ subpat` we must establish any bindings in `subpat`
`176`	`176`	// before establishing the binding for `x`.
`@@ -209,6 +209,7 @@ impl<'tcx> MatchPairTree<'tcx> {`
`209`	`209`	`source,`
`210`	`210`	`var_id: var,`
`211`	`211`	`binding_mode: mode,`
	`212`	`+ is_shorthand,`
`212`	`213`	`}));`
`213`	`214`	`}`
`214`	`215`