Suggest using :: instead of . in more cases.

When `Foo.field` or `Foo.method()` exprs are encountered, suggest `Foo::field` or `Foo::method()` when Foo is a type alias, not just
a struct, trait, or module.

Also rename test for this suggestion from issue-22692.rs to something more meaningful.

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -1566,7 +1566,7 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
             }
         };
 
-        let mut bad_struct_syntax_suggestion = |this: &mut Self, def_id: DefId| {
+        let bad_struct_syntax_suggestion = |this: &mut Self, err: &mut Diag<'_>, def_id: DefId| {
             let (followed_by_brace, closing_brace) = this.followed_by_brace(span);
 
             match source {
@@ -1740,12 +1740,10 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                 }
             }
             (
-                Res::Def(kind @ (DefKind::Mod | DefKind::Trait), _),
+                Res::Def(kind @ (DefKind::Mod | DefKind::Trait | DefKind::TyAlias), _),
                 PathSource::Expr(Some(parent)),
-            ) => {
+            ) if path_sep(self, err, parent, kind) => {
-                if !path_sep(self, err, parent, kind) {
+                return true;
-                    return false;
-                }
             }
             (
                 Res::Def(DefKind::Enum, def_id),
@@ -1777,13 +1775,13 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                 let (ctor_def, ctor_vis, fields) = if let Some(struct_ctor) = struct_ctor {
                     if let PathSource::Expr(Some(parent)) = source {
                         if let ExprKind::Field(..) | ExprKind::MethodCall(..) = parent.kind {
-                            bad_struct_syntax_suggestion(self, def_id);
+                            bad_struct_syntax_suggestion(self, err, def_id);
                             return true;
                         }
                     }
                     struct_ctor
                 } else {
-                    bad_struct_syntax_suggestion(self, def_id);
+                    bad_struct_syntax_suggestion(self, err, def_id);
                     return true;
                 };
 
@@ -1861,7 +1859,7 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                 err.span_label(span, "constructor is not visible here due to private fields");
             }
             (Res::Def(DefKind::Union | DefKind::Variant, def_id), _) if ns == ValueNS => {
-                bad_struct_syntax_suggestion(self, def_id);
+                bad_struct_syntax_suggestion(self, err, def_id);
             }
             (Res::Def(DefKind::Ctor(_, CtorKind::Const), def_id), _) if ns == ValueNS => {
                 match source {

src/tools/tidy/src/issues.txt

@@ -3619,7 +3619,6 @@ ui/resolve/issue-21221-1.rs
 ui/resolve/issue-21221-2.rs
 ui/resolve/issue-21221-3.rs
 ui/resolve/issue-21221-4.rs
-ui/resolve/issue-22692.rs
 ui/resolve/issue-2330.rs
 ui/resolve/issue-23305.rs
 ui/resolve/issue-2356.rs

tests/ui/resolve/dot-notation-type-namespace-suggest-path-sep.rs

@@ -1,3 +1,11 @@
+// see also https://github.com/rust-lang/rust/issues/22692
+
+type Alias = Vec<u32>;
+
+mod foo {
+    fn bar() {}
+}
+
 fn main() {
     let _ = String.new();
     //~^ ERROR expected value, found struct `String`
@@ -10,6 +18,18 @@ fn main() {
     let _ = Vec::<()>.with_capacity(1);
     //~^ ERROR expected value, found struct `Vec`
     //~| HELP use the path separator
+
+    let _ = Alias.new();
+    //~^ ERROR expected value, found type alias `Alias`
+    //~| HELP use the path separator
+
+    let _ = Alias.default;
+    //~^ ERROR expected value, found type alias `Alias`
+    //~| HELP use the path separator
+
+    let _ = foo.bar;
+    //~^ ERROR expected value, found module `foo`
+    //~| HELP use the path separator
 }
 
 macro_rules! Type {

tests/ui/resolve/dot-notation-type-namespace-suggest-path-sep.stderr

@@ -1,5 +1,5 @@
 error[E0423]: expected value, found struct `String`
-  --> $DIR/issue-22692.rs:2:13
+  --> $DIR/dot-notation-type-namespace-suggest-path-sep.rs:10:13
    |
 LL |     let _ = String.new();
    |             ^^^^^^
@@ -11,7 +11,7 @@ LL +     let _ = String::new();
    |
 
 error[E0423]: expected value, found struct `String`
-  --> $DIR/issue-22692.rs:6:13
+  --> $DIR/dot-notation-type-namespace-suggest-path-sep.rs:14:13
    |
 LL |     let _ = String.default;
    |             ^^^^^^
@@ -23,7 +23,7 @@ LL +     let _ = String::default;
    |
 
 error[E0423]: expected value, found struct `Vec`
-  --> $DIR/issue-22692.rs:10:13
+  --> $DIR/dot-notation-type-namespace-suggest-path-sep.rs:18:13
    |
 LL |     let _ = Vec::<()>.with_capacity(1);
    |             ^^^^^^^^^
@@ -34,8 +34,41 @@ LL -     let _ = Vec::<()>.with_capacity(1);
 LL +     let _ = Vec::<()>::with_capacity(1);
    |
 
+error[E0423]: expected value, found type alias `Alias`
+  --> $DIR/dot-notation-type-namespace-suggest-path-sep.rs:22:13
+   |
+LL |     let _ = Alias.new();
+   |             ^^^^^
+   |
+help: use the path separator to refer to an item
+   |
+LL |     let _ = Alias::new();
+   |                  ~~
+
+error[E0423]: expected value, found type alias `Alias`
+  --> $DIR/dot-notation-type-namespace-suggest-path-sep.rs:26:13
+   |
+LL |     let _ = Alias.default;
+   |             ^^^^^
+   |
+help: use the path separator to refer to an item
+   |
+LL |     let _ = Alias::default;
+   |                  ~~
+
+error[E0423]: expected value, found module `foo`
+  --> $DIR/dot-notation-type-namespace-suggest-path-sep.rs:30:13
+   |
+LL |     let _ = foo.bar;
+   |             ^^^
+   |
+help: use the path separator to refer to an item
+   |
+LL |     let _ = foo::bar;
+   |                ~~
+
 error[E0423]: expected value, found struct `std::cell::Cell`
-  --> $DIR/issue-22692.rs:17:9
+  --> $DIR/dot-notation-type-namespace-suggest-path-sep.rs:37:9
    |
 LL |         ::std::cell::Cell
    |         ^^^^^^^^^^^^^^^^^
@@ -51,7 +84,7 @@ LL +     <Type!()>::get();
    |
 
 error[E0423]: expected value, found struct `std::cell::Cell`
-  --> $DIR/issue-22692.rs:17:9
+  --> $DIR/dot-notation-type-namespace-suggest-path-sep.rs:37:9
    |
 LL |         ::std::cell::Cell
    |         ^^^^^^^^^^^^^^^^^
@@ -67,7 +100,7 @@ LL +     <Type! {}>::get;
    |
 
 error[E0423]: expected value, found struct `Vec`
-  --> $DIR/issue-22692.rs:26:9
+  --> $DIR/dot-notation-type-namespace-suggest-path-sep.rs:46:9
    |
 LL |         Vec.new()
    |         ^^^
@@ -83,7 +116,7 @@ LL +         Vec::new()
    |
 
 error[E0423]: expected value, found struct `Vec`
-  --> $DIR/issue-22692.rs:31:9
+  --> $DIR/dot-notation-type-namespace-suggest-path-sep.rs:51:9
    |
 LL |         Vec.new
    |         ^^^
@@ -99,7 +132,7 @@ LL +         Vec::new
    |
 
 error[E0423]: expected value, found struct `std::cell::Cell`
-  --> $DIR/issue-22692.rs:17:9
+  --> $DIR/dot-notation-type-namespace-suggest-path-sep.rs:37:9
    |
 LL |         ::std::cell::Cell
    |         ^^^^^^^^^^^^^^^^^
@@ -114,6 +147,6 @@ LL -         Type!().new(0)
 LL +         <Type!()>::new(0)
    |
 
-error: aborting due to 8 previous errors
+error: aborting due to 11 previous errors
 
 For more information about this error, try `rustc --explain E0423`.