tests: add tests for #112630

Signed-off-by: David Wood <david@davidtw.co>

Author: davidtwco

tests/ui/cast/issue-112630-1.rs

@@ -0,0 +1,6 @@
+fn f(_: B) {}
+//~^ ERROR cannot find type `B` in this scope [E0412]
+
+fn main() {
+    let _ = [0; f as usize];
+}

tests/ui/cast/issue-112630-1.stderr

@@ -0,0 +1,14 @@
+error[E0412]: cannot find type `B` in this scope
+  --> $DIR/issue-112630-1.rs:1:9
+   |
+LL | fn f(_: B) {}
+   |         ^ not found in this scope
+   |
+help: you might be missing a type parameter
+   |
+LL | fn f<B>(_: B) {}
+   |     +++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0412`.

tests/ui/cast/issue-112630.rs

@@ -0,0 +1,8 @@
+enum Foo {
+    Bar(B),
+    //~^ ERROR cannot find type `B` in this scope [E0412]
+}
+
+fn main() {
+    let _ = [0; Foo::Bar as usize];
+}

tests/ui/cast/issue-112630.stderr

@@ -0,0 +1,14 @@
+error[E0412]: cannot find type `B` in this scope
+  --> $DIR/issue-112630.rs:2:9
+   |
+LL |     Bar(B),
+   |         ^ not found in this scope
+   |
+help: you might be missing a type parameter
+   |
+LL | enum Foo<B> {
+   |         +++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0412`.