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Usman Akinyemi
8b6f7fbd8d
When a function returns `impl Trait`, all branches must return the same
concrete type. Previously, the compiler showed:
expected `First` because of return type
This was misleading, as it suggested the return type was `First`, rather
than any single type implementing the trait.
Update the diagnostic to:
expected a single type implementing `Value` because of return type
Also highlight the first return expression to make it clearer why
subsequent returns do not match.
Signed-off-by: Usman Akinyemi <usmanakinyemi202@gmail.com>
48 lines
1.5 KiB
Plaintext
48 lines
1.5 KiB
Plaintext
error[E0308]: mismatched types
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--> $DIR/equality.rs:17:5
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LL | fn two(x: bool) -> impl Foo {
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| -------- expected a single type implementing `Foo` because of return type
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LL | if x {
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LL | return 1_i32;
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| ----- return type resolved to be `i32`
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LL | }
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LL | 0_u32
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| ^^^^^ expected `i32`, found `u32`
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help: change the type of the numeric literal from `u32` to `i32`
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LL - 0_u32
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LL + 0_i32
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error[E0277]: cannot add `impl Foo` to `u32`
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--> $DIR/equality.rs:26:11
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LL | n + sum_to(n - 1)
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| ^ no implementation for `u32 + impl Foo`
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= help: the trait `Add<impl Foo>` is not implemented for `u32`
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help: the following other types implement trait `Add<Rhs>`
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--> $SRC_DIR/core/src/ops/arith.rs:LL:COL
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= note: `u32` implements `Add`
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::: $SRC_DIR/core/src/ops/arith.rs:LL:COL
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= note: in this macro invocation
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--> $SRC_DIR/core/src/internal_macros.rs:LL:COL
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= note: `&u32` implements `Add<u32>`
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::: $SRC_DIR/core/src/internal_macros.rs:LL:COL
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= note: `u32` implements `Add<&u32>`
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::: $SRC_DIR/core/src/internal_macros.rs:LL:COL
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= note: `&u32` implements `Add`
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= note: this error originates in the macro `add_impl` (in Nightly builds, run with -Z macro-backtrace for more info)
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error: aborting due to 2 previous errors
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Some errors have detailed explanations: E0277, E0308.
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For more information about an error, try `rustc --explain E0277`.
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