enum-variant-generic-args: describe + account for unit variants.

src/test/ui/type-alias-enum-variants/enum-variant-generic-args.rs

@@ -1,4 +1,10 @@
-enum Enum<T> { TSVariant(T), SVariant { v: T } }
+// Checks that applied type arguments of enums, and aliases to them, are respected.
+// For example, `Self` is never a type constructor. Therefore, no types can be applied to it.
+//
+// We also check that the variant to an type-aliased enum cannot be type applied whether
+// that alias is generic or monomorphic.
+
+enum Enum<T> { TSVariant(T), SVariant { v: T }, UVariant }
 type Alias<T> = Enum<T>;
 type AliasFixed = Enum<()>;
 
@@ -30,6 +36,16 @@ impl<T> Enum<T> {
         //~^^ ERROR type arguments are not allowed for this type [E0109]
         //~^^^ ERROR mismatched types [E0308]
     }
+
+    fn u_variant() {
+        Self::UVariant::<()>;
+        //~^ ERROR type arguments are not allowed for this type [E0109]
+        Self::<()>::UVariant;
+        //~^ ERROR type arguments are not allowed for this type [E0109]
+        Self::<()>::UVariant::<()>;
+        //~^ ERROR type arguments are not allowed for this type [E0109]
+        //~^^ ERROR type arguments are not allowed for this type [E0109]
+    }
 }
 
 fn main() {
@@ -68,4 +84,22 @@ fn main() {
     AliasFixed::<()>::SVariant::<()> { v: () };
     //~^ ERROR type arguments are not allowed for this type [E0109]
     //~^^ ERROR wrong number of type arguments: expected 0, found 1 [E0107]
+
+    // Unit variant
+
+    Enum::<()>::UVariant::<()>;
+    //~^ ERROR type arguments are not allowed for this type [E0109]
+
+    Alias::UVariant::<()>;
+    //~^ ERROR type arguments are not allowed for this type [E0109]
+    Alias::<()>::UVariant::<()>;
+    //~^ ERROR type arguments are not allowed for this type [E0109]
+
+    AliasFixed::UVariant::<()>;
+    //~^ ERROR type arguments are not allowed for this type [E0109]
+    AliasFixed::<()>::UVariant;
+    //~^ ERROR wrong number of type arguments: expected 0, found 1 [E0107]
+    AliasFixed::<()>::UVariant::<()>;
+    //~^ ERROR type arguments are not allowed for this type [E0109]
+    //~^^ ERROR wrong number of type arguments: expected 0, found 1 [E0107]
 }

src/test/ui/type-alias-enum-variants/enum-variant-generic-args.stderr

@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/enum-variant-generic-args.rs:7:25
+  --> $DIR/enum-variant-generic-args.rs:13:25
    |
 LL |         Self::TSVariant(());
    |                         ^^ expected type parameter, found ()
@@ -8,19 +8,19 @@ LL |         Self::TSVariant(());
               found type `()`
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:9:27
+  --> $DIR/enum-variant-generic-args.rs:15:27
    |
 LL |         Self::TSVariant::<()>(());
    |                           ^^ type argument not allowed
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:11:16
+  --> $DIR/enum-variant-generic-args.rs:17:16
    |
 LL |         Self::<()>::TSVariant(());
    |                ^^ type argument not allowed
 
 error[E0308]: mismatched types
-  --> $DIR/enum-variant-generic-args.rs:11:31
+  --> $DIR/enum-variant-generic-args.rs:17:31
    |
 LL |         Self::<()>::TSVariant(());
    |                               ^^ expected type parameter, found ()
@@ -29,19 +29,19 @@ LL |         Self::<()>::TSVariant(());
               found type `()`
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:14:16
+  --> $DIR/enum-variant-generic-args.rs:20:16
    |
 LL |         Self::<()>::TSVariant::<()>(());
    |                ^^ type argument not allowed
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:14:33
+  --> $DIR/enum-variant-generic-args.rs:20:33
    |
 LL |         Self::<()>::TSVariant::<()>(());
    |                                 ^^ type argument not allowed
 
 error[E0308]: mismatched types
-  --> $DIR/enum-variant-generic-args.rs:20:29
+  --> $DIR/enum-variant-generic-args.rs:26:29
    |
 LL |         Self::SVariant { v: () };
    |                             ^^ expected type parameter, found ()
@@ -50,13 +50,13 @@ LL |         Self::SVariant { v: () };
               found type `()`
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:22:26
+  --> $DIR/enum-variant-generic-args.rs:28:26
    |
 LL |         Self::SVariant::<()> { v: () };
    |                          ^^ type argument not allowed
 
 error[E0308]: mismatched types
-  --> $DIR/enum-variant-generic-args.rs:22:35
+  --> $DIR/enum-variant-generic-args.rs:28:35
    |
 LL |         Self::SVariant::<()> { v: () };
    |                                   ^^ expected type parameter, found ()
@@ -65,13 +65,13 @@ LL |         Self::SVariant::<()> { v: () };
               found type `()`
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:25:16
+  --> $DIR/enum-variant-generic-args.rs:31:16
    |
 LL |         Self::<()>::SVariant { v: () };
    |                ^^ type argument not allowed
 
 error[E0308]: mismatched types
-  --> $DIR/enum-variant-generic-args.rs:25:35
+  --> $DIR/enum-variant-generic-args.rs:31:35
    |
 LL |         Self::<()>::SVariant { v: () };
    |                                   ^^ expected type parameter, found ()
@@ -80,19 +80,19 @@ LL |         Self::<()>::SVariant { v: () };
               found type `()`
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:28:16
+  --> $DIR/enum-variant-generic-args.rs:34:16
    |
 LL |         Self::<()>::SVariant::<()> { v: () };
    |                ^^ type argument not allowed
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:28:32
+  --> $DIR/enum-variant-generic-args.rs:34:32
    |
 LL |         Self::<()>::SVariant::<()> { v: () };
    |                                ^^ type argument not allowed
 
 error[E0308]: mismatched types
-  --> $DIR/enum-variant-generic-args.rs:28:41
+  --> $DIR/enum-variant-generic-args.rs:34:41
    |
 LL |         Self::<()>::SVariant::<()> { v: () };
    |                                         ^^ expected type parameter, found ()
@@ -101,90 +101,156 @@ LL |         Self::<()>::SVariant::<()> { v: () };
               found type `()`
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:38:29
+  --> $DIR/enum-variant-generic-args.rs:41:26
+   |
+LL |         Self::UVariant::<()>;
+   |                          ^^ type argument not allowed
+
+error[E0109]: type arguments are not allowed for this type
+  --> $DIR/enum-variant-generic-args.rs:43:16
+   |
+LL |         Self::<()>::UVariant;
+   |                ^^ type argument not allowed
+
+error[E0109]: type arguments are not allowed for this type
+  --> $DIR/enum-variant-generic-args.rs:45:16
+   |
+LL |         Self::<()>::UVariant::<()>;
+   |                ^^ type argument not allowed
+
+error[E0109]: type arguments are not allowed for this type
+  --> $DIR/enum-variant-generic-args.rs:45:32
+   |
+LL |         Self::<()>::UVariant::<()>;
+   |                                ^^ type argument not allowed
+
+error[E0109]: type arguments are not allowed for this type
+  --> $DIR/enum-variant-generic-args.rs:54:29
    |
 LL |     Enum::<()>::TSVariant::<()>(());
    |                             ^^ type argument not allowed
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:41:24
+  --> $DIR/enum-variant-generic-args.rs:57:24
    |
 LL |     Alias::TSVariant::<()>(());
    |                        ^^ type argument not allowed
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:43:30
+  --> $DIR/enum-variant-generic-args.rs:59:30
    |
 LL |     Alias::<()>::TSVariant::<()>(());
    |                              ^^ type argument not allowed
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:46:29
+  --> $DIR/enum-variant-generic-args.rs:62:29
    |
 LL |     AliasFixed::TSVariant::<()>(());
    |                             ^^ type argument not allowed
 
 error[E0107]: wrong number of type arguments: expected 0, found 1
-  --> $DIR/enum-variant-generic-args.rs:48:18
+  --> $DIR/enum-variant-generic-args.rs:64:18
    |
 LL |     AliasFixed::<()>::TSVariant(());
    |                  ^^ unexpected type argument
 
 error[E0107]: wrong number of type arguments: expected 0, found 1
-  --> $DIR/enum-variant-generic-args.rs:50:18
+  --> $DIR/enum-variant-generic-args.rs:66:18
    |
 LL |     AliasFixed::<()>::TSVariant::<()>(());
    |                  ^^ unexpected type argument
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:50:35
+  --> $DIR/enum-variant-generic-args.rs:66:35
    |
 LL |     AliasFixed::<()>::TSVariant::<()>(());
    |                                   ^^ type argument not allowed
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:56:28
+  --> $DIR/enum-variant-generic-args.rs:72:28
    |
 LL |     Enum::<()>::SVariant::<()> { v: () };
    |                            ^^ type argument not allowed
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:59:23
+  --> $DIR/enum-variant-generic-args.rs:75:23
    |
 LL |     Alias::SVariant::<()> { v: () };
    |                       ^^ type argument not allowed
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:61:29
+  --> $DIR/enum-variant-generic-args.rs:77:29
    |
 LL |     Alias::<()>::SVariant::<()> { v: () };
    |                             ^^ type argument not allowed
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:64:28
+  --> $DIR/enum-variant-generic-args.rs:80:28
    |
 LL |     AliasFixed::SVariant::<()> { v: () };
    |                            ^^ type argument not allowed
 
 error[E0107]: wrong number of type arguments: expected 0, found 1
-  --> $DIR/enum-variant-generic-args.rs:66:18
+  --> $DIR/enum-variant-generic-args.rs:82:18
    |
 LL |     AliasFixed::<()>::SVariant { v: () };
    |                  ^^ unexpected type argument
 
 error[E0107]: wrong number of type arguments: expected 0, found 1
-  --> $DIR/enum-variant-generic-args.rs:68:18
+  --> $DIR/enum-variant-generic-args.rs:84:18
    |
 LL |     AliasFixed::<()>::SVariant::<()> { v: () };
    |                  ^^ unexpected type argument
 
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/enum-variant-generic-args.rs:68:34
+  --> $DIR/enum-variant-generic-args.rs:84:34
    |
 LL |     AliasFixed::<()>::SVariant::<()> { v: () };
    |                                  ^^ type argument not allowed
 
-error: aborting due to 28 previous errors
+error[E0109]: type arguments are not allowed for this type
+  --> $DIR/enum-variant-generic-args.rs:90:28
+   |
+LL |     Enum::<()>::UVariant::<()>;
+   |                            ^^ type argument not allowed
+
+error[E0109]: type arguments are not allowed for this type
+  --> $DIR/enum-variant-generic-args.rs:93:23
+   |
+LL |     Alias::UVariant::<()>;
+   |                       ^^ type argument not allowed
+
+error[E0109]: type arguments are not allowed for this type
+  --> $DIR/enum-variant-generic-args.rs:95:29
+   |
+LL |     Alias::<()>::UVariant::<()>;
+   |                             ^^ type argument not allowed
+
+error[E0109]: type arguments are not allowed for this type
+  --> $DIR/enum-variant-generic-args.rs:98:28
+   |
+LL |     AliasFixed::UVariant::<()>;
+   |                            ^^ type argument not allowed
+
+error[E0107]: wrong number of type arguments: expected 0, found 1
+  --> $DIR/enum-variant-generic-args.rs:100:18
+   |
+LL |     AliasFixed::<()>::UVariant;
+   |                  ^^ unexpected type argument
+
+error[E0107]: wrong number of type arguments: expected 0, found 1
+  --> $DIR/enum-variant-generic-args.rs:102:18
+   |
+LL |     AliasFixed::<()>::UVariant::<()>;
+   |                  ^^ unexpected type argument
+
+error[E0109]: type arguments are not allowed for this type
+  --> $DIR/enum-variant-generic-args.rs:102:34
+   |
+LL |     AliasFixed::<()>::UVariant::<()>;
+   |                                  ^^ type argument not allowed
+
+error: aborting due to 39 previous errors
 
 Some errors have detailed explanations: E0107, E0109, E0308.
 For more information about an error, try `rustc --explain E0107`.