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Can define a associated type more than once #23969

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Kimundi opened this issue Apr 2, 2015 · 3 comments
Closed

Can define a associated type more than once #23969

Kimundi opened this issue Apr 2, 2015 · 3 comments
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A-associated-items Area: Associated items (types, constants & functions) A-type-system Area: Type system P-medium Medium priority

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@Kimundi
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Kimundi commented Apr 2, 2015 

trait Foo {
    type Ty;
}

impl Foo for () {
    type Ty = ();
    type Ty = usize;
}

fn main() { 
    let _: <() as Foo>::Ty = ();
}

This erroneously parses and compiles fine, the compiler seems to use the first definition of Ty in the impl.

This might have been introduced by #23265, ping @eddyb.
@Kimundi Kimundi added the A-parser Area: The parsing of Rust source code to an AST label Apr 2, 2015
@alexcrichton
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triage: I-nominated

@nikomatsakis nikomatsakis added the A-associated-items Area: Associated items (types, constants & functions) label Apr 2, 2015
@nrc nrc added A-associated-items Area: Associated items (types, constants & functions) and removed A-associated-items Area: Associated items (types, constants & functions) A-parser Area: The parsing of Rust source code to an AST labels Apr 2, 2015
@pnkfelix
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pnkfelix commented Apr 2, 2015

classifying as just a bug. P-backcompat-lang, not 1.0 blocker.

@brson brson added P-medium Medium priority A-type-system Area: Type system and removed P-backcompat-lang labels Apr 24, 2015
@brson
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brson commented Apr 24, 2015

Demoting this to P-medium. Somebody should get on it though!

nham pushed a commit to nham/rust that referenced this issue Jun 3, 2015
Detect duplicate implementations of assoc. types and constants.
7ac997d 
Adds error codes E0398 and E0399.

Fixes rust-lang#23969.
@nham nham mentioned this issue Jun 3, 2015
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nham pushed a commit to nham/rust that referenced this issue Jul 15, 2015
Better detection of duplicate associated items.
560bb0a 
Expands E0201 to be used for any duplicate associated items, not just duplicate
methods/functions. It also correctly detects when two different kinds of items
(like a constant and a method) have the same name.

Fixes rust-lang#23969.
Manishearth added a commit to Manishearth/rust that referenced this issue Jul 17, 2015
@Manishearth
Rollup merge of rust-lang#25993 - nham:fix_23969, r=nikomatsakis
ef9b9ce 
Adds two error codes, one for duplicate associated constants and one for types. I'm not certain these should each have their own code, but E0201 is already solely for duplicate associated functions so at least it kinda matches. This will lead to somewhat redundant error explanations, but that's nothing new!

Fixes rust-lang#23969.
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A-associated-items Area: Associated items (types, constants & functions) A-type-system Area: Type system P-medium Medium priority
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@alexcrichton @brson @nikomatsakis @pnkfelix @nrc @Kimundi @rust-highfive