diff --git a/crates/hir-ty/src/infer/expr.rs b/crates/hir-ty/src/infer/expr.rs index 3d762b174a..f5eb37f427 100644 --- a/crates/hir-ty/src/infer/expr.rs +++ b/crates/hir-ty/src/infer/expr.rs @@ -1759,13 +1759,14 @@ impl InferenceContext<'_> { skip_indices: &[u32], is_varargs: bool, ) { - if args.len() != param_tys.len() + skip_indices.len() && !is_varargs { + let arg_count_mismatch = args.len() != param_tys.len() + skip_indices.len() && !is_varargs; + if arg_count_mismatch { self.push_diagnostic(InferenceDiagnostic::MismatchedArgCount { call_expr: expr, expected: param_tys.len() + skip_indices.len(), found: args.len(), }); - } + }; // Quoting https://github.com/rust-lang/rust/blob/6ef275e6c3cb1384ec78128eceeb4963ff788dca/src/librustc_typeck/check/mod.rs#L3325 -- // We do this in a pretty awful way: first we type-check any arguments @@ -1819,7 +1820,7 @@ impl InferenceContext<'_> { // The function signature may contain some unknown types, so we need to insert // type vars here to avoid type mismatch false positive. let coercion_target = self.insert_type_vars(coercion_target); - if self.coerce(Some(arg), &ty, &coercion_target).is_err() { + if self.coerce(Some(arg), &ty, &coercion_target).is_err() && !arg_count_mismatch { self.result.type_mismatches.insert( arg.into(), TypeMismatch { expected: coercion_target, actual: ty.clone() }, diff --git a/crates/ide-diagnostics/src/handlers/mismatched_arg_count.rs b/crates/ide-diagnostics/src/handlers/mismatched_arg_count.rs index 56ec45c898..7126617cde 100644 --- a/crates/ide-diagnostics/src/handlers/mismatched_arg_count.rs +++ b/crates/ide-diagnostics/src/handlers/mismatched_arg_count.rs @@ -472,4 +472,18 @@ fn f( "#, ) } + + #[test] + fn no_type_mismatches_when_arg_count_mismatch() { + check_diagnostics( + r#" +fn foo((): (), (): ()) { + foo(1, 2, 3); + // ^^ error: expected 2 arguments, found 3 + foo(1); + // ^ error: expected 2 arguments, found 1 +} +"#, + ); + } }