diff options
Diffstat (limited to 'compiler/rustc_mir_build/src')
| -rw-r--r-- | compiler/rustc_mir_build/src/thir/pattern/check_match.rs | 29 |
1 files changed, 25 insertions, 4 deletions
diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs index a8830b346ae..edd51b521fa 100644 --- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs +++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs @@ -1116,13 +1116,13 @@ fn report_non_exhaustive_match<'p, 'tcx>( if ty.is_ptr_sized_integral() { if ty.inner() == cx.tcx.types.usize { err.note(format!( - "`{ty}` does not have a fixed maximum value, so half-open ranges are necessary to match \ - exhaustively", + "`{ty}` does not have a fixed maximum value, so half-open ranges are \ + necessary to match exhaustively", )); } else if ty.inner() == cx.tcx.types.isize { err.note(format!( - "`{ty}` does not have fixed minimum and maximum values, so half-open ranges are necessary to match \ - exhaustively", + "`{ty}` does not have fixed minimum and maximum values, so half-open \ + ranges are necessary to match exhaustively", )); } } else if ty.inner() == cx.tcx.types.str_ { @@ -1143,6 +1143,27 @@ fn report_non_exhaustive_match<'p, 'tcx>( } } + for &arm in arms { + let arm = &thir.arms[arm]; + if let PatKind::Constant { opt_def: Some(def_id), .. } = arm.pattern.kind { + let const_name = cx.tcx.item_name(def_id); + err.span_label( + arm.pattern.span, + format!( + "this pattern doesn't introduce a new catch-all binding, but rather pattern \ + matches against the value of constant `{const_name}`", + ), + ); + err.span_note(cx.tcx.def_span(def_id), format!("constant `{const_name}` defined here")); + err.span_suggestion_verbose( + arm.pattern.span.shrink_to_hi(), + "if you meant to introduce a binding, use a different name", + "_var".to_string(), + Applicability::MaybeIncorrect, + ); + } + } + // Whether we suggest the actual missing patterns or `_`. let suggest_the_witnesses = witnesses.len() < 4; let suggested_arm = if suggest_the_witnesses { |