hir-ty, ide-diagnostics: use E0057/E0061 for arg-count mismatch (was E0107) - #22947
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The MismatchedArgCount diagnostic previously used code E0107, which is actually 'wrong number of generic arguments'. Split it based on how the call is made: - E0057 for calls through the Fn/FnMut/FnOnce traits (arguments bundled into a tuple via TupleArgumentsFlag::TupleArguments in the inference code) - E0061 for regular function calls This adds an is_fn_trait_call flag on InferenceDiagnostic::MismatchedArgCount and the hir-surface MismatchedArgCount struct, populated from the tuple_arguments flag already tracked by check_call_arguments. The downstream 'if !args_count_matches' push in infer/expr.rs already covers both paths, so the two FIXMEs at the top of the tuple branch are addressed by threading the kind through rather than by adding a new push site. The nightly-only fallback FIXME below (E0059-ish) is left alone per discussion on rust-lang#22140. Adds a test 'arg_count_multi_arg_closure' that exercises the multi-argument tuple case via a closure with signature |_a: u8, _b: u8|. This complements the existing 'arg_count_lambda' test (1-tuple case). Refs rust-lang#22140
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Thanks for the review and the E0057/E0061 pointer. |
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The MismatchedArgCount diagnostic previously used code E0107, which is actually 'wrong number of generic arguments'. Split it based on how the call is made:
This adds an is_fn_trait_call flag on InferenceDiagnostic::MismatchedArgCount and the hir-surface MismatchedArgCount struct, populated from the tuple_arguments flag already tracked by check_call_arguments. The downstream 'if !args_count_matches' push in infer/expr.rs already covers both paths, so the two FIXMEs at the top of the tuple branch are addressed by threading the kind through rather than by adding a new push site. The nightly-only fallback FIXME below (E0059-ish) is left alone per discussion on issue #22140.
Adds a test 'arg_count_multi_arg_closure' that exercises the multi-argument tuple case via a closure with signature |_a: u8, _b: u8|. This complements the existing 'arg_count_lambda' test (1-tuple case).
Refs #22140