From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- .../rustc_error_codes/src/error_codes/E0411.md | 56 ++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 compiler/rustc_error_codes/src/error_codes/E0411.md (limited to 'compiler/rustc_error_codes/src/error_codes/E0411.md') diff --git a/compiler/rustc_error_codes/src/error_codes/E0411.md b/compiler/rustc_error_codes/src/error_codes/E0411.md new file mode 100644 index 000000000..d82171533 --- /dev/null +++ b/compiler/rustc_error_codes/src/error_codes/E0411.md @@ -0,0 +1,56 @@ +The `Self` keyword was used outside an impl, trait, or type definition. + +Erroneous code example: + +```compile_fail,E0411 +::foo; // error: use of `Self` outside of an impl, trait, or type + // definition +``` + +The `Self` keyword represents the current type, which explains why it can only +be used inside an impl, trait, or type definition. It gives access to the +associated items of a type: + +``` +trait Foo { + type Bar; +} + +trait Baz : Foo { + fn bar() -> Self::Bar; // like this +} +``` + +However, be careful when two types have a common associated type: + +```compile_fail +trait Foo { + type Bar; +} + +trait Foo2 { + type Bar; +} + +trait Baz : Foo + Foo2 { + fn bar() -> Self::Bar; + // error: ambiguous associated type `Bar` in bounds of `Self` +} +``` + +This problem can be solved by specifying from which trait we want to use the +`Bar` type: + +``` +trait Foo { + type Bar; +} + +trait Foo2 { + type Bar; +} + +trait Baz : Foo + Foo2 { + fn bar() -> ::Bar; // ok! +} +``` -- cgit v1.2.3