diff --git a/src/ir.cpp b/src/ir.cpp index 62927f46a0..40f853531f 100644 --- a/src/ir.cpp +++ b/src/ir.cpp @@ -7492,6 +7492,19 @@ static ImplicitCastMatchResult ir_types_match_with_implicit_cast(IrAnalyze *ira, } } + // implicit enum to &const union which has the enum as the tag type + if (actual_type->id == TypeTableEntryIdEnum && expected_type->id == TypeTableEntryIdPointer) { + TypeTableEntry *union_type = expected_type->data.pointer.child_type; + if (union_type->data.unionation.decl_node->data.container_decl.auto_enum || + union_type->data.unionation.decl_node->data.container_decl.init_arg_expr != nullptr) + { + type_ensure_zero_bits_known(ira->codegen, union_type); + if (union_type->data.unionation.tag_type == actual_type) { + return ImplicitCastMatchResultYes; + } + } + } + // implicit undefined literal to anything if (actual_type->id == TypeTableEntryIdUndefLit) { return ImplicitCastMatchResultYes; @@ -9079,6 +9092,27 @@ static IrInstruction *ir_analyze_cast(IrAnalyze *ira, IrInstruction *source_inst } } + // explicit enum to &const union which has the enum as the tag type + if (actual_type->id == TypeTableEntryIdEnum && wanted_type->id == TypeTableEntryIdPointer) { + TypeTableEntry *union_type = wanted_type->data.pointer.child_type; + if (union_type->data.unionation.decl_node->data.container_decl.auto_enum || + union_type->data.unionation.decl_node->data.container_decl.init_arg_expr != nullptr) + { + type_ensure_zero_bits_known(ira->codegen, union_type); + if (union_type->data.unionation.tag_type == actual_type) { + IrInstruction *cast1 = ir_analyze_cast(ira, source_instr, union_type, value); + if (type_is_invalid(cast1->value.type)) + return ira->codegen->invalid_instruction; + + IrInstruction *cast2 = ir_analyze_cast(ira, source_instr, wanted_type, cast1); + if (type_is_invalid(cast2->value.type)) + return ira->codegen->invalid_instruction; + + return cast2; + } + } + } + // explicit cast from undefined to anything if (actual_type->id == TypeTableEntryIdUndefLit) { return ir_analyze_undefined_to_anything(ira, source_instr, value, wanted_type); diff --git a/test/cases/union.zig b/test/cases/union.zig index 7c1c04c711..90d869289f 100644 --- a/test/cases/union.zig +++ b/test/cases/union.zig @@ -206,3 +206,17 @@ test "implicit cast union to its tag type" { fn giveMeLetterB(x: Letter2) { assert(x == Value2.B); } + +test "implicit cast from @EnumTagType(TheUnion) to &const TheUnion" { + assertIsTheUnion2Item1(TheUnion2.Item1); +} + +const TheUnion2 = union(enum) { + Item1, + Item2: i32, +}; + +fn assertIsTheUnion2Item1(value: &const TheUnion2) { + assert(*value == TheUnion2.Item1); +} +