error: This generic shadows the built-in type `u32` --> $DIR/builtin-type-shadow.rs:5:8 | 5 | fn foo(a: u32) -> u32 { | ^^^ | = note: `-D builtin-type-shadow` implied by `-D warnings` error[E0308]: mismatched types --> $DIR/builtin-type-shadow.rs:6:5 | 5 | fn foo(a: u32) -> u32 { | --- expected `u32` because of return type 6 | 42 | ^^ expected type parameter, found integral variable | = note: expected type `u32` found type `{integer}`