diff options
3 files changed, 26 insertions, 0 deletions
diff --git a/compiler/rustc_hir_typeck/src/demand.rs b/compiler/rustc_hir_typeck/src/demand.rs index 65ec2f232ae..3b09fdda0ce 100644 --- a/compiler/rustc_hir_typeck/src/demand.rs +++ b/compiler/rustc_hir_typeck/src/demand.rs @@ -983,6 +983,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { } else { return false; } + let e_ok = args_e.type_at(0); + let f_ok = args_f.type_at(0); + if !self.infcx.can_eq(self.param_env, f_ok, e_ok) { + return false; + } let e = args_e.type_at(1); let f = args_f.type_at(1); if self diff --git a/tests/ui/type/type-check/issue-116967-cannot-coerce-returned-result.rs b/tests/ui/type/type-check/issue-116967-cannot-coerce-returned-result.rs new file mode 100644 index 00000000000..adf3049b4ba --- /dev/null +++ b/tests/ui/type/type-check/issue-116967-cannot-coerce-returned-result.rs @@ -0,0 +1,6 @@ +fn foo() -> Result<String, ()> { + let out: Result<(), ()> = Ok(()); + out //~ ERROR mismatched types +} + +fn main() {} diff --git a/tests/ui/type/type-check/issue-116967-cannot-coerce-returned-result.stderr b/tests/ui/type/type-check/issue-116967-cannot-coerce-returned-result.stderr new file mode 100644 index 00000000000..447b22a152d --- /dev/null +++ b/tests/ui/type/type-check/issue-116967-cannot-coerce-returned-result.stderr @@ -0,0 +1,15 @@ +error[E0308]: mismatched types + --> $DIR/issue-116967-cannot-coerce-returned-result.rs:3:5 + | +LL | fn foo() -> Result<String, ()> { + | ------------------ expected `Result<String, ()>` because of return type +LL | let out: Result<(), ()> = Ok(()); +LL | out + | ^^^ expected `Result<String, ()>`, found `Result<(), ()>` + | + = note: expected enum `Result<String, _>` + found enum `Result<(), _>` + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0308`. |