suggest wrapping in struct tuples as well

compiler/rustc_typeck/src/check/demand.rs

@@ -268,10 +268,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expr_ty: Ty<'tcx>,
     ) {
         if let ty::Adt(expected_adt, substs) = expected.kind() {
-            if !expected_adt.is_enum() {
-                return;
-            }
-
             // If the expression is of type () and it's the return expression of a block,
             // we suggest adding a separate return expression instead.
             // (To avoid things like suggesting `Ok(while .. { .. })`.)

src/test/ui/did_you_mean/compatible-variants.rs

@@ -69,6 +69,8 @@ enum A {
     B { b: B},
 }
 
+struct A2(B);
+
 enum B {
     Fst,
     Snd,
@@ -78,4 +80,11 @@ fn foo() {
     // We don't want to suggest `A::B(B::Fst)` here.
     let a: A = B::Fst;
     //~^ ERROR mismatched types
-}
+}
+
+fn bar() {
+    // But we _do_ want to suggest `A2(B::Fst)` here!
+    let a: A2 = B::Fst;
+    //~^ ERROR mismatched types
+    //~| HELP try wrapping
+}

src/test/ui/did_you_mean/compatible-variants.stderr

@@ -191,13 +191,26 @@ LL |     let _ = Foo { bar: Some(bar) };
    |                   ++++++++++   +
 
 error[E0308]: mismatched types
-  --> $DIR/compatible-variants.rs:79:16
+  --> $DIR/compatible-variants.rs:81:16
    |
 LL |     let a: A = B::Fst;
    |            -   ^^^^^^ expected enum `A`, found enum `B`
    |            |
    |            expected due to this
 
-error: aborting due to 12 previous errors
+error[E0308]: mismatched types
+  --> $DIR/compatible-variants.rs:87:17
+   |
+LL |     let a: A2 = B::Fst;
+   |            --   ^^^^^^ expected struct `A2`, found enum `B`
+   |            |
+   |            expected due to this
+   |
+help: try wrapping the expression in `A2`
+   |
+LL |     let a: A2 = A2(B::Fst);
+   |                 +++      +
+
+error: aborting due to 13 previous errors
 
 For more information about this error, try `rustc --explain E0308`.