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-rw-r--r-- | compiler/rustc_error_codes/src/error_codes/E0790.md | 47 |
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diff --git a/compiler/rustc_error_codes/src/error_codes/E0790.md b/compiler/rustc_error_codes/src/error_codes/E0790.md new file mode 100644 index 000000000..2aee9dfbd --- /dev/null +++ b/compiler/rustc_error_codes/src/error_codes/E0790.md @@ -0,0 +1,47 @@ +You need to specify a specific implementation of the trait in order to call the +method. + +Erroneous code example: + +```compile_fail,E0790 +trait Generator { + fn create() -> u32; +} + +struct Impl; + +impl Generator for Impl { + fn create() -> u32 { 1 } +} + +struct AnotherImpl; + +impl Generator for AnotherImpl { + fn create() -> u32 { 2 } +} + +let cont: u32 = Generator::create(); +// error, impossible to choose one of Generator trait implementation +// Should it be Impl or AnotherImpl, maybe something else? +``` + +This error can be solved by adding type annotations that provide the missing +information to the compiler. In this case, the solution is to use a concrete +type: + +``` +trait Generator { + fn create() -> u32; +} + +struct AnotherImpl; + +impl Generator for AnotherImpl { + fn create() -> u32 { 2 } +} + +let gen1 = AnotherImpl::create(); + +// if there are multiple methods with same name (different traits) +let gen2 = <AnotherImpl as Generator>::create(); +``` |