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-rw-r--r-- | compiler/rustc_error_codes/src/error_codes/E0698.md | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/compiler/rustc_error_codes/src/error_codes/E0698.md b/compiler/rustc_error_codes/src/error_codes/E0698.md new file mode 100644 index 000000000..3ba992a84 --- /dev/null +++ b/compiler/rustc_error_codes/src/error_codes/E0698.md @@ -0,0 +1,25 @@ +When using generators (or async) all type variables must be bound so a +generator can be constructed. + +Erroneous code example: + +```edition2018,compile_fail,E0698 +async fn bar<T>() -> () {} + +async fn foo() { + bar().await; // error: cannot infer type for `T` +} +``` + +In the above example `T` is unknowable by the compiler. +To fix this you must bind `T` to a concrete type such as `String` +so that a generator can then be constructed: + +```edition2018 +async fn bar<T>() -> () {} + +async fn foo() { + bar::<String>().await; + // ^^^^^^^^ specify type explicitly +} +``` |