Rollup merge of #101493 - spastorino:borrow-mut-impl-trait-context, r=oli-obk

Pass ImplTraitContext as &mut to avoid the need of ImplTraitContext::reborrow

`@oli-obk` requested this and other changes as a way of simplifying #101345. This is just going to make the diff of #101345 smaller.

r? `@oli-obk` `@cjgillot`

Author: matthiaskrgr

compiler/rustc_ast_lowering/src/asm.rs

@@ -220,7 +220,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                                 &sym.qself,
                                 &sym.path,
                                 ParamMode::Optional,
-                                ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                                &mut ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                             );
                             hir::InlineAsmOperand::SymStatic { path, def_id }
                         } else {

compiler/rustc_ast_lowering/src/block.rs

@@ -84,10 +84,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     }
 
     fn lower_local(&mut self, l: &Local) -> &'hir hir::Local<'hir> {
-        let ty = l
-            .ty
-            .as_ref()
-            .map(|t| self.lower_ty(t, ImplTraitContext::Disallowed(ImplTraitPosition::Variable)));
+        let ty = l.ty.as_ref().map(|t| {
+            self.lower_ty(t, &mut ImplTraitContext::Disallowed(ImplTraitPosition::Variable))
+        });
         let init = l.kind.init().map(|init| self.lower_expr(init));
         let hir_id = self.lower_node_id(l.id);
         let pat = self.lower_pat(&l.pat);

compiler/rustc_ast_lowering/src/expr.rs

@@ -66,7 +66,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         seg,
                         ParamMode::Optional,
                         ParenthesizedGenericArgs::Err,
-                        ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                        &mut ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                     ));
                     let receiver = self.lower_expr(receiver);
                     let args =
@@ -89,14 +89,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 }
                 ExprKind::Cast(ref expr, ref ty) => {
                     let expr = self.lower_expr(expr);
-                    let ty =
-                        self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
+                    let ty = self
+                        .lower_ty(ty, &mut ImplTraitContext::Disallowed(ImplTraitPosition::Type));
                     hir::ExprKind::Cast(expr, ty)
                 }
                 ExprKind::Type(ref expr, ref ty) => {
                     let expr = self.lower_expr(expr);
-                    let ty =
-                        self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
+                    let ty = self
+                        .lower_ty(ty, &mut ImplTraitContext::Disallowed(ImplTraitPosition::Type));
                     hir::ExprKind::Type(expr, ty)
                 }
                 ExprKind::AddrOf(k, m, ref ohs) => {
@@ -219,7 +219,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         qself,
                         path,
                         ParamMode::Optional,
-                        ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                        &mut ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                     );
                     hir::ExprKind::Path(qpath)
                 }
@@ -253,7 +253,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                             &se.qself,
                             &se.path,
                             ParamMode::Optional,
-                            ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                            &mut ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                         )),
                         self.arena
                             .alloc_from_iter(se.fields.iter().map(|x| self.lower_expr_field(x))),
@@ -550,12 +550,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
         async_gen_kind: hir::AsyncGeneratorKind,
         body: impl FnOnce(&mut Self) -> hir::Expr<'hir>,
     ) -> hir::ExprKind<'hir> {
-        let output = match ret_ty {
-            Some(ty) => hir::FnRetTy::Return(
-                self.lower_ty(&ty, ImplTraitContext::Disallowed(ImplTraitPosition::AsyncBlock)),
-            ),
-            None => hir::FnRetTy::DefaultReturn(self.lower_span(span)),
-        };
+        let output =
+            match ret_ty {
+                Some(ty) => hir::FnRetTy::Return(self.lower_ty(
+                    &ty,
+                    &mut ImplTraitContext::Disallowed(ImplTraitPosition::AsyncBlock),
+                )),
+                None => hir::FnRetTy::DefaultReturn(self.lower_span(span)),
+            };
 
         // Resume argument type. We let the compiler infer this to simplify the lowering. It is
         // fully constrained by `future::from_generator`.
@@ -1123,7 +1125,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         qself,
                         path,
                         ParamMode::Optional,
-                        ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                        &mut ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                     );
                     // Destructure like a tuple struct.
                     let tuple_struct_pat =
@@ -1139,7 +1141,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         qself,
                         path,
                         ParamMode::Optional,
-                        ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                        &mut ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                     );
                     // Destructure like a unit struct.
                     let unit_struct_pat = hir::PatKind::Path(qpath);
@@ -1163,7 +1165,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     &se.qself,
                     &se.path,
                     ParamMode::Optional,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                    &mut ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                 );
                 let fields_omitted = match &se.rest {
                     StructRest::Base(e) => {