diff options
| -rw-r--r-- | src/mir/from_hir_match.cpp | 38 |
1 files changed, 27 insertions, 11 deletions
diff --git a/src/mir/from_hir_match.cpp b/src/mir/from_hir_match.cpp index d127c6d1..e1e90705 100644 --- a/src/mir/from_hir_match.cpp +++ b/src/mir/from_hir_match.cpp @@ -66,11 +66,13 @@ void MIR_LowerHIR_Match_DecisionTree( MirBuilder& builder, MirConverter& conv, : struct PatternRulesetBuilder { const StaticTraitResolve& m_resolve; + bool m_is_impossible; ::std::vector<PatternRule> m_rules; PatternRule::field_path_t m_field_path; PatternRulesetBuilder(const StaticTraitResolve& resolve): - m_resolve(resolve) + m_resolve(resolve), + m_is_impossible(false) {} void append_from_lit(const Span& sp, const ::HIR::Literal& lit, const ::HIR::TypeRef& ty); @@ -115,16 +117,21 @@ void MIR_LowerHIR_Match( MirBuilder& builder, MirConverter& conv, ::HIR::ExprNod // - Define variables from the first pattern conv.define_vars_from(node.span(), arm.m_patterns.front()); - unsigned int pat_idx = 0; - for( const auto& pat : arm.m_patterns ) + for( unsigned int pat_idx = 0; pat_idx < arm.m_patterns.size(); pat_idx ++ ) { - + const auto& pat = arm.m_patterns[pat_idx]; // - Convert HIR pattern into ruleset auto pat_builder = PatternRulesetBuilder { builder.resolve() }; pat_builder.append_from(node.span(), pat, node.m_value->m_res_type); - arm_rules.push_back( PatternRuleset { arm_idx, pat_idx, mv$(pat_builder.m_rules) } ); - - DEBUG("ARM PAT (" << arm_idx << "," << pat_idx << ") " << pat << " ==> [" << arm_rules.back().m_rules << "]"); + if( pat_builder.m_is_impossible ) + { + DEBUG("ARM PAT (" << arm_idx << "," << pat_idx << ") " << pat << " ==> IMPOSSIBLE [" << pat_builder.m_rules << "]"); + } + else + { + DEBUG("ARM PAT (" << arm_idx << "," << pat_idx << ") " << pat << " ==> [" << pat_builder.m_rules << "]"); + arm_rules.push_back( PatternRuleset { arm_idx, pat_idx, mv$(pat_builder.m_rules) } ); + } // - Emit code to destructure the matched pattern ac.destructures.push_back( builder.new_bb_unlinked() ); @@ -132,8 +139,6 @@ void MIR_LowerHIR_Match( MirBuilder& builder, MirConverter& conv, ::HIR::ExprNod conv.destructure_from( arm.m_code->span(), pat, match_val.clone(), true ); builder.pause_cur_block(); // NOTE: Paused block resumed upon successful match - - pat_idx += 1; } // Condition @@ -183,7 +188,7 @@ void MIR_LowerHIR_Match( MirBuilder& builder, MirConverter& conv, ::HIR::ExprNod // - Go to the next block builder.end_block( ::MIR::Terminator::make_Goto(next_block) ); } - + arm_code.push_back( mv$(ac) ); } @@ -634,7 +639,11 @@ void PatternRulesetBuilder::append_from(const Span& sp, const ::HIR::Pattern& pa TU_MATCHA( (ty.m_data), (e), (Infer, BUG(sp, "Ivar for in match type"); ), - (Diverge, BUG(sp, "Diverge in match type"); ), + (Diverge, + // Since ! can never exist, mark this arm as impossible. + // TODO: Marking as impossible (and not emitting) leads to exhuaustiveness failure. + //this->m_is_impossible = true; + ), (Primitive, TU_MATCH_DEF(::HIR::Pattern::Data, (pat.m_data), (pe), ( BUG(sp, "Matching primitive with invalid pattern - " << pat); ), @@ -884,6 +893,8 @@ void PatternRulesetBuilder::append_from(const Span& sp, const ::HIR::Pattern& pa sub_builder.append_from( sp, subpat, subty ); } + if( sub_builder.m_is_impossible ) + this->m_is_impossible = true; this->push_rule( PatternRule::make_Variant({ pe.binding_idx, mv$(sub_builder.m_rules) }) ); ), (EnumStruct, @@ -917,6 +928,8 @@ void PatternRulesetBuilder::append_from(const Span& sp, const ::HIR::Pattern& pa sub_builder.append_from( sp, subpat, subty ); } } + if( sub_builder.m_is_impossible ) + this->m_is_impossible = true; this->push_rule( PatternRule::make_Variant({ pe.binding_idx, mv$(sub_builder.m_rules) }) ); ) ) @@ -1077,6 +1090,9 @@ void MIR_LowerHIR_Match_Simple( MirBuilder& builder, MirConverter& conv, ::HIR:: for( unsigned int i = 0; i < arm.m_patterns.size(); i ++ ) { + if( arm_code.destructures[i] == 0 ) + continue ; + const auto& pat_rule = arm_rules[rule_idx]; bool is_last_pat = (i+1 == arm.m_patterns.size()); auto next_pattern_bb = (!is_last_pat ? builder.new_bb_unlinked() : next_arm_bb); |