diff options
Diffstat (limited to 'compiler/rustc_mir_build/src/thir/pattern/check_match.rs')
| -rw-r--r-- | compiler/rustc_mir_build/src/thir/pattern/check_match.rs | 119 |
1 files changed, 75 insertions, 44 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 8f58db504..1e51cb9aa 100644 --- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs +++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs @@ -26,8 +26,8 @@ use rustc_session::Session; use rustc_span::hygiene::DesugaringKind; use rustc_span::Span; -pub(crate) fn check_match(tcx: TyCtxt<'_>, def_id: LocalDefId) { - let Ok((thir, expr)) = tcx.thir_body(ty::WithOptConstParam::unknown(def_id)) else { return }; +pub(crate) fn check_match(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(), ErrorGuaranteed> { + let (thir, expr) = tcx.thir_body(def_id)?; let thir = thir.borrow(); let pattern_arena = TypedArena::default(); let mut visitor = MatchVisitor { @@ -37,13 +37,16 @@ pub(crate) fn check_match(tcx: TyCtxt<'_>, def_id: LocalDefId) { lint_level: tcx.hir().local_def_id_to_hir_id(def_id), let_source: LetSource::None, pattern_arena: &pattern_arena, + error: Ok(()), }; visitor.visit_expr(&thir[expr]); + for param in thir.params.iter() { if let Some(box ref pattern) = param.pat { visitor.check_irrefutable(pattern, "function argument", None); } } + visitor.error } fn create_e0004( @@ -77,6 +80,7 @@ struct MatchVisitor<'a, 'p, 'tcx> { lint_level: HirId, let_source: LetSource, pattern_arena: &'p TypedArena<DeconstructedPat<'p, 'tcx>>, + error: Result<(), ErrorGuaranteed>, } impl<'a, 'tcx> Visitor<'a, 'tcx> for MatchVisitor<'a, '_, 'tcx> { @@ -86,35 +90,34 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for MatchVisitor<'a, '_, 'tcx> { #[instrument(level = "trace", skip(self))] fn visit_arm(&mut self, arm: &Arm<'tcx>) { - match arm.guard { - Some(Guard::If(expr)) => { - self.with_let_source(LetSource::IfLetGuard, |this| { - this.visit_expr(&this.thir[expr]) - }); - } - Some(Guard::IfLet(ref pat, expr)) => { - self.with_let_source(LetSource::IfLetGuard, |this| { - this.check_let(pat, expr, LetSource::IfLetGuard, pat.span); - this.visit_pat(pat); - this.visit_expr(&this.thir[expr]); - }); + self.with_lint_level(arm.lint_level, |this| { + match arm.guard { + Some(Guard::If(expr)) => { + this.with_let_source(LetSource::IfLetGuard, |this| { + this.visit_expr(&this.thir[expr]) + }); + } + Some(Guard::IfLet(ref pat, expr)) => { + this.with_let_source(LetSource::IfLetGuard, |this| { + this.check_let(pat, expr, LetSource::IfLetGuard, pat.span); + this.visit_pat(pat); + this.visit_expr(&this.thir[expr]); + }); + } + None => {} } - None => {} - } - self.visit_pat(&arm.pattern); - self.visit_expr(&self.thir[arm.body]); + this.visit_pat(&arm.pattern); + this.visit_expr(&self.thir[arm.body]); + }); } #[instrument(level = "trace", skip(self))] fn visit_expr(&mut self, ex: &Expr<'tcx>) { match ex.kind { ExprKind::Scope { value, lint_level, .. } => { - let old_lint_level = self.lint_level; - if let LintLevel::Explicit(hir_id) = lint_level { - self.lint_level = hir_id; - } - self.visit_expr(&self.thir[value]); - self.lint_level = old_lint_level; + self.with_lint_level(lint_level, |this| { + this.visit_expr(&this.thir[value]); + }); return; } ExprKind::If { cond, then, else_opt, if_then_scope: _ } => { @@ -186,6 +189,17 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> { self.let_source = old_let_source; } + fn with_lint_level(&mut self, new_lint_level: LintLevel, f: impl FnOnce(&mut Self)) { + if let LintLevel::Explicit(hir_id) = new_lint_level { + let old_lint_level = self.lint_level; + self.lint_level = hir_id; + f(self); + self.lint_level = old_lint_level; + } else { + f(self); + } + } + fn check_patterns(&self, pat: &Pat<'tcx>, rf: RefutableFlag) { pat.walk_always(|pat| check_borrow_conflicts_in_at_patterns(self, pat)); check_for_bindings_named_same_as_variants(self, pat, rf); @@ -232,7 +246,9 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> { for &arm in arms { // Check the arm for some things unrelated to exhaustiveness. let arm = &self.thir.arms[arm]; - self.check_patterns(&arm.pattern, Refutable); + self.with_lint_level(arm.lint_level, |this| { + this.check_patterns(&arm.pattern, Refutable); + }); } let tarms: Vec<_> = arms @@ -276,9 +292,9 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> { let [pat_field] = &subpatterns[..] else { bug!() }; self.check_irrefutable(&pat_field.pattern, "`for` loop binding", None); } else { - non_exhaustive_match( + self.error = Err(non_exhaustive_match( &cx, self.thir, scrut_ty, scrut.span, witnesses, arms, expr_span, - ); + )); } } } @@ -406,7 +422,7 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> { } #[instrument(level = "trace", skip(self))] - fn check_irrefutable(&self, pat: &Pat<'tcx>, origin: &str, sp: Option<Span>) { + fn check_irrefutable(&mut self, pat: &Pat<'tcx>, origin: &str, sp: Option<Span>) { let mut cx = self.new_cx(self.lint_level, false); let pattern = self.lower_pattern(&mut cx, pat); @@ -475,18 +491,36 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> { AdtDefinedHere { adt_def_span, ty, variants } }; - self.tcx.sess.emit_err(PatternNotCovered { + // Emit an extra note if the first uncovered witness would be uninhabited + // if we disregard visibility. + let witness_1_is_privately_uninhabited = + if cx.tcx.features().exhaustive_patterns + && let Some(witness_1) = witnesses.get(0) + && let ty::Adt(adt, substs) = witness_1.ty().kind() + && adt.is_enum() + && let Constructor::Variant(variant_index) = witness_1.ctor() + { + let variant = adt.variant(*variant_index); + let inhabited = variant.inhabited_predicate(cx.tcx, *adt).subst(cx.tcx, substs); + assert!(inhabited.apply(cx.tcx, cx.param_env, cx.module)); + !inhabited.apply_ignore_module(cx.tcx, cx.param_env) + } else { + false + }; + + self.error = Err(self.tcx.sess.emit_err(PatternNotCovered { span: pat.span, origin, uncovered: Uncovered::new(pat.span, &cx, witnesses), inform, interpreted_as_const, + witness_1_is_privately_uninhabited: witness_1_is_privately_uninhabited.then_some(()), _p: (), pattern_ty, let_suggestion, misc_suggestion, adt_defined_here, - }); + })); } } @@ -628,7 +662,7 @@ fn non_exhaustive_match<'p, 'tcx>( witnesses: Vec<DeconstructedPat<'p, 'tcx>>, arms: &[ArmId], expr_span: Span, -) { +) -> ErrorGuaranteed { let is_empty_match = arms.is_empty(); let non_empty_enum = match scrut_ty.kind() { ty::Adt(def, _) => def.is_enum() && !def.variants().is_empty(), @@ -640,13 +674,12 @@ fn non_exhaustive_match<'p, 'tcx>( let pattern; let patterns_len; if is_empty_match && !non_empty_enum { - cx.tcx.sess.emit_err(NonExhaustivePatternsTypeNotEmpty { + return cx.tcx.sess.emit_err(NonExhaustivePatternsTypeNotEmpty { cx, expr_span, span: sp, ty: scrut_ty, }); - return; } else { // FIXME: migration of this diagnostic will require list support let joined_patterns = joined_uncovered_patterns(cx, &witnesses); @@ -668,13 +701,11 @@ fn non_exhaustive_match<'p, 'tcx>( }; }; - let is_variant_list_non_exhaustive = match scrut_ty.kind() { - ty::Adt(def, _) if def.is_variant_list_non_exhaustive() && !def.did().is_local() => true, - _ => false, - }; + let is_variant_list_non_exhaustive = matches!(scrut_ty.kind(), + ty::Adt(def, _) if def.is_variant_list_non_exhaustive() && !def.did().is_local()); adt_defined_here(cx, &mut err, scrut_ty, &witnesses); - err.note(&format!( + err.note(format!( "the matched value is of type `{}`{}", scrut_ty, if is_variant_list_non_exhaustive { ", which is marked as non-exhaustive" } else { "" } @@ -684,13 +715,13 @@ fn non_exhaustive_match<'p, 'tcx>( && witnesses.len() == 1 && matches!(witnesses[0].ctor(), Constructor::NonExhaustive) { - err.note(&format!( + err.note(format!( "`{}` does not have a fixed maximum value, so a wildcard `_` is necessary to match \ exhaustively", scrut_ty, )); if cx.tcx.sess.is_nightly_build() { - err.help(&format!( + err.help(format!( "add `#![feature(precise_pointer_size_matching)]` to the crate attributes to \ enable precise `{}` matching", scrut_ty, @@ -795,11 +826,11 @@ fn non_exhaustive_match<'p, 'tcx>( }, ); if let Some((span, sugg)) = suggestion { - err.span_suggestion_verbose(span, &msg, sugg, Applicability::HasPlaceholders); + err.span_suggestion_verbose(span, msg, sugg, Applicability::HasPlaceholders); } else { - err.help(&msg); + err.help(msg); } - err.emit(); + err.emit() } pub(crate) fn joined_uncovered_patterns<'p, 'tcx>( @@ -859,7 +890,7 @@ fn adt_defined_here<'p, 'tcx>( for pat in spans { span.push_span_label(pat, "not covered"); } - err.span_note(span, &format!("`{}` defined here", ty)); + err.span_note(span, format!("`{}` defined here", ty)); } } |