"Unreachable pattern" if matched variant is not imported

[vhbit]

enum Foo {
  Bar,
  Baz
}

impl Foo {
   fn foo(&self) {
      match self {
         &Bar => println!("bar"),
         &Baz => println!("baz"),
      }
   }
}

It reports unreachable pattern:

test.rs:12:9: 12:13 error: unreachable pattern [E0001]
test.rs:12         &Baz => println!("baz"), 
                   ^~~~
test.rs:12:9: 12:13 help: pass `--explain E0001` to see a detailed explanation

while actually it should report unknown identifier

[0xc0170]

I can confirm this with the latest rust nightly (rustc 0.13.0-nightly (336349c 2014-11-17 20:37:19 +0000)

In zinc there are some enums and then match in the code, which did not reflect the latest changes in namespaced enums, thus reported as unreachable pattern, but once namespace was added, it built without errors.

[vhbit]

I've actually seen it long before namespaced enums reform (so it is not related to it) in macros, but didn't bother reporting as though it was just a problem with macros.

[mahkoh]

This is working as expected.

     match self {
         &Bar => println!("bar"),
      }

is equivalent to

{
    let &Bar = self;
    println!("bar");
}

[vhbit]

@mahkoh aha, it seems to be actually explanation why it happens - in example you've provided it also shows a warning "unused variable Bar". So looks like Bar and Baz are treated as "bind a variable Bar to value of self". In my sample it means that indeed, Baz arm is unreachable.

[klutzy]

Yes, Bar is not imported so it's working as wildcard variable. See also #10402 and #10304.

[ghost]

Closing as a dupe of #10402.