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Diffstat (limited to 'compiler/rustc_error_codes/src/error_codes/E0049.md')
-rw-r--r-- | compiler/rustc_error_codes/src/error_codes/E0049.md | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/compiler/rustc_error_codes/src/error_codes/E0049.md b/compiler/rustc_error_codes/src/error_codes/E0049.md new file mode 100644 index 000000000..a2034a342 --- /dev/null +++ b/compiler/rustc_error_codes/src/error_codes/E0049.md @@ -0,0 +1,36 @@ +An attempted implementation of a trait method has the wrong number of type or +const parameters. + +Erroneous code example: + +```compile_fail,E0049 +trait Foo { + fn foo<T: Default>(x: T) -> Self; +} + +struct Bar; + +// error: method `foo` has 0 type parameters but its trait declaration has 1 +// type parameter +impl Foo for Bar { + fn foo(x: bool) -> Self { Bar } +} +``` + +For example, the `Foo` trait has a method `foo` with a type parameter `T`, +but the implementation of `foo` for the type `Bar` is missing this parameter. +To fix this error, they must have the same type parameters: + +``` +trait Foo { + fn foo<T: Default>(x: T) -> Self; +} + +struct Bar; + +impl Foo for Bar { + fn foo<T: Default>(x: T) -> Self { // ok! + Bar + } +} +``` |