Emit explanatory note for functions in trait and impl items as well

Author: FabianWolff

compiler/rustc_typeck/src/check/expr.rs

@@ -683,11 +683,23 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
             let encl_item_id = self.tcx.hir().get_parent_item(expr.hir_id);
 
-            // Somewhat confusingly, get_parent_item() does not necessarily return an
-            // item -- it can also return a Foreign-/Impl-/TraitItem or a Crate (see
-            // issue #86721). If it does, we still report the same error.
-            if let Some(hir::Node::Item(encl_item)) = self.tcx.hir().find(encl_item_id) {
-                if let hir::ItemKind::Fn(..) = encl_item.kind {
+            if self.tcx.hir().maybe_body_owned_by(encl_item_id).is_some() {
+                if let Some(hir::Node::Item(hir::Item {
+                    kind: hir::ItemKind::Fn(..),
+                    span: encl_fn_span,
+                    ..
+                }))
+                | Some(hir::Node::TraitItem(hir::TraitItem {
+                    kind: hir::TraitItemKind::Fn(..),
+                    span: encl_fn_span,
+                    ..
+                }))
+                | Some(hir::Node::ImplItem(hir::ImplItem {
+                    kind: hir::ImplItemKind::Fn(..),
+                    span: encl_fn_span,
+                    ..
+                })) = self.tcx.hir().find(encl_item_id)
+                {
                     // We are inside a function body, so reporting "return statement
                     // outside of function body" needs an explanation.
 
@@ -701,7 +713,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     let encl_body = self.tcx.hir().body(encl_body_id);
 
                     err.encl_body_span = Some(encl_body.value.span);
-                    err.encl_fn_span = Some(encl_item.span);
+                    err.encl_fn_span = Some(*encl_fn_span);
                 }
             }
 

src/test/ui/return/issue-86188-return-not-in-fn-body.rs

@@ -12,6 +12,25 @@ const C: [(); 42] = {
     }]
 };
 
+struct S {}
+trait Tr {
+    fn foo();
+    fn bar() {
+    //~^ NOTE: ...not the enclosing function body
+        [(); return];
+        //~^ ERROR: return statement outside of function body [E0572]
+        //~| NOTE: the return is part of this body...
+    }
+}
+impl Tr for S {
+    fn foo() {
+    //~^ NOTE: ...not the enclosing function body
+        [(); return];
+        //~^ ERROR: return statement outside of function body [E0572]
+        //~| NOTE: the return is part of this body...
+    }
+}
+
 fn main() {
 //~^ NOTE: ...not the enclosing function body
     [(); return || {

src/test/ui/return/issue-86188-return-not-in-fn-body.stderr

@@ -9,7 +9,31 @@ LL | |     }]
    | |_____^
 
 error[E0572]: return statement outside of function body
-  --> $DIR/issue-86188-return-not-in-fn-body.rs:17:10
+  --> $DIR/issue-86188-return-not-in-fn-body.rs:20:14
+   |
+LL | /     fn bar() {
+LL | |
+LL | |         [(); return];
+   | |              ^^^^^^ the return is part of this body...
+LL | |
+LL | |
+LL | |     }
+   | |_____- ...not the enclosing function body
+
+error[E0572]: return statement outside of function body
+  --> $DIR/issue-86188-return-not-in-fn-body.rs:28:14
+   |
+LL | /     fn foo() {
+LL | |
+LL | |         [(); return];
+   | |              ^^^^^^ the return is part of this body...
+LL | |
+LL | |
+LL | |     }
+   | |_____- ...not the enclosing function body
+
+error[E0572]: return statement outside of function body
+  --> $DIR/issue-86188-return-not-in-fn-body.rs:36:10
    |
 LL |  / fn main() {
 LL |  |
@@ -23,6 +47,6 @@ LL | ||     }];
 LL |  | }
    |  |_- ...not the enclosing function body
 
-error: aborting due to 2 previous errors
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0572`.

src/test/ui/typeck/issue-86721-return-expr-ice.stderr renamed to src/test/ui/typeck/issue-86721-return-expr-ice.rev1.stderr

@@ -1,5 +1,5 @@
 error[E0572]: return statement outside of function body
-  --> $DIR/issue-86721-return-expr-ice.rs:6:22
+  --> $DIR/issue-86721-return-expr-ice.rs:9:22
    |
 LL |     const U: usize = return;
    |                      ^^^^^^

src/test/ui/typeck/issue-86721-return-expr-ice.rev2.stderr

@@ -0,0 +1,9 @@
+error[E0572]: return statement outside of function body
+  --> $DIR/issue-86721-return-expr-ice.rs:15:20
+   |
+LL |     fn foo(a: [(); return]);
+   |                    ^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0572`.

src/test/ui/typeck/issue-86721-return-expr-ice.rs

@@ -1,8 +1,17 @@
 // Regression test for the ICE described in #86721.
 
+// revisions: rev1 rev2
+#![cfg_attr(any(), rev1, rev2)]
 #![crate_type="lib"]
 
+#[cfg(any(rev1))]
 trait T {
     const U: usize = return;
-    //~^ ERROR: return statement outside of function body [E0572]
+    //[rev1]~^ ERROR: return statement outside of function body [E0572]
+}
+
+#[cfg(any(rev2))]
+trait T2 {
+    fn foo(a: [(); return]);
+    //[rev2]~^ ERROR: return statement outside of function body [E0572]
 }