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-rw-r--r-- | compiler/rustc_error_codes/src/error_codes/E0229.md | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/compiler/rustc_error_codes/src/error_codes/E0229.md b/compiler/rustc_error_codes/src/error_codes/E0229.md new file mode 100644 index 000000000..a8fab057d --- /dev/null +++ b/compiler/rustc_error_codes/src/error_codes/E0229.md @@ -0,0 +1,38 @@ +An associated type binding was done outside of the type parameter declaration +and `where` clause. + +Erroneous code example: + +```compile_fail,E0229 +pub trait Foo { + type A; + fn boo(&self) -> <Self as Foo>::A; +} + +struct Bar; + +impl Foo for isize { + type A = usize; + fn boo(&self) -> usize { 42 } +} + +fn baz<I>(x: &<I as Foo<A=Bar>>::A) {} +// error: associated type bindings are not allowed here +``` + +To solve this error, please move the type bindings in the type parameter +declaration: + +``` +# struct Bar; +# trait Foo { type A; } +fn baz<I: Foo<A=Bar>>(x: &<I as Foo>::A) {} // ok! +``` + +Or in the `where` clause: + +``` +# struct Bar; +# trait Foo { type A; } +fn baz<I>(x: &<I as Foo>::A) where I: Foo<A=Bar> {} +``` |