error[E0284]: type annotations needed --> $DIR/issue-69455.rs:29:41 | LL | println!("{}", 23u64.test(xs.iter().sum())); | ---- ^^^ cannot infer type of the type parameter `S` declared on the associated function `sum` | | | type must be known at this point | = note: cannot satisfy `>::Output == _` help: consider specifying the generic argument | LL | println!("{}", 23u64.test(xs.iter().sum::())); | +++++ error[E0283]: type annotations needed --> $DIR/issue-69455.rs:29:41 | LL | println!("{}", 23u64.test(xs.iter().sum())); | ---- ^^^ cannot infer type of the type parameter `S` declared on the associated function `sum` | | | required by a bound introduced by this call | note: multiple `impl`s satisfying `u64: Test<_>` found --> $DIR/issue-69455.rs:11:1 | LL | impl Test for u64 { | ^^^^^^^^^^^^^^^^^^^^^^ ... LL | impl Test for u64 { | ^^^^^^^^^^^^^^^^^^^^^^ help: consider specifying the generic argument | LL | println!("{}", 23u64.test(xs.iter().sum::())); | +++++ error: aborting due to 2 previous errors Some errors have detailed explanations: E0283, E0284. For more information about an error, try `rustc --explain E0283`.