add implicit cast from enum to union
when the enum is the tag type of the union and is comptime known to be of a void field of the union See #642master
parent
63a2f9a8b2
commit
960914a073
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@ -2244,12 +2244,10 @@ static void resolve_union_zero_bits(CodeGen *g, TypeTableEntry *union_type) {
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TypeTableEntry *enum_type = analyze_type_expr(g, scope, enum_type_node);
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if (type_is_invalid(enum_type)) {
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union_type->data.unionation.is_invalid = true;
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union_type->data.unionation.embedded_in_current = false;
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return;
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}
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if (enum_type->id != TypeTableEntryIdEnum) {
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union_type->data.unionation.is_invalid = true;
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union_type->data.unionation.embedded_in_current = false;
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add_node_error(g, enum_type_node,
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buf_sprintf("expected enum tag type, found '%s'", buf_ptr(&enum_type->name)));
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return;
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@ -3319,7 +3317,7 @@ TypeStructField *find_struct_type_field(TypeTableEntry *type_entry, Buf *name) {
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TypeUnionField *find_union_type_field(TypeTableEntry *type_entry, Buf *name) {
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assert(type_entry->id == TypeTableEntryIdUnion);
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assert(type_entry->data.unionation.complete);
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assert(type_entry->data.unionation.zero_bits_known);
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for (uint32_t i = 0; i < type_entry->data.unionation.src_field_count; i += 1) {
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TypeUnionField *field = &type_entry->data.unionation.fields[i];
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if (buf_eql_buf(field->enum_field->name, name)) {
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@ -3331,7 +3329,7 @@ TypeUnionField *find_union_type_field(TypeTableEntry *type_entry, Buf *name) {
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TypeUnionField *find_union_field_by_tag(TypeTableEntry *type_entry, const BigInt *tag) {
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assert(type_entry->id == TypeTableEntryIdUnion);
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assert(type_entry->data.unionation.complete);
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assert(type_entry->data.unionation.zero_bits_known);
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assert(type_entry->data.unionation.gen_tag_index != SIZE_MAX);
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for (uint32_t i = 0; i < type_entry->data.unionation.src_field_count; i += 1) {
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TypeUnionField *field = &type_entry->data.unionation.fields[i];
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@ -3888,7 +3886,6 @@ bool handle_is_ptr(TypeTableEntry *type_entry) {
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return false;
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case TypeTableEntryIdArray:
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case TypeTableEntryIdStruct:
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case TypeTableEntryIdUnion:
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return type_has_bits(type_entry);
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case TypeTableEntryIdErrorUnion:
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return type_has_bits(type_entry->data.error.child_type);
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@ -3896,6 +3893,14 @@ bool handle_is_ptr(TypeTableEntry *type_entry) {
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return type_has_bits(type_entry->data.maybe.child_type) &&
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type_entry->data.maybe.child_type->id != TypeTableEntryIdPointer &&
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type_entry->data.maybe.child_type->id != TypeTableEntryIdFn;
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case TypeTableEntryIdUnion:
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assert(type_entry->data.unionation.complete);
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if (type_entry->data.unionation.gen_field_count == 0)
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return false;
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if (!type_has_bits(type_entry))
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return false;
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return true;
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}
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zig_unreachable();
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}
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@ -3946,8 +3946,6 @@ static LLVMValueRef gen_const_val(CodeGen *g, ConstExprValue *const_val) {
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case TypeTableEntryIdUnion:
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{
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LLVMTypeRef union_type_ref = type_entry->data.unionation.union_type_ref;
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ConstExprValue *payload_value = const_val->data.x_union.payload;
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assert(payload_value != nullptr);
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if (type_entry->data.unionation.gen_field_count == 0) {
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if (type_entry->data.unionation.gen_tag_index == SIZE_MAX) {
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@ -3960,7 +3958,8 @@ static LLVMValueRef gen_const_val(CodeGen *g, ConstExprValue *const_val) {
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LLVMValueRef union_value_ref;
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bool make_unnamed_struct;
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if (!type_has_bits(payload_value->type)) {
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ConstExprValue *payload_value = const_val->data.x_union.payload;
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if (payload_value == nullptr || !type_has_bits(payload_value->type)) {
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if (type_entry->data.unionation.gen_tag_index == SIZE_MAX)
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return LLVMGetUndef(type_entry->type_ref);
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79
src/ir.cpp
79
src/ir.cpp
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@ -7468,6 +7468,17 @@ static ImplicitCastMatchResult ir_types_match_with_implicit_cast(IrAnalyze *ira,
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}
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}
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// implicit enum to union which has the enum as the tag type
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if (expected_type->id == TypeTableEntryIdUnion && actual_type->id == TypeTableEntryIdEnum &&
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(expected_type->data.unionation.decl_node->data.container_decl.auto_enum ||
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expected_type->data.unionation.decl_node->data.container_decl.init_arg_expr != nullptr))
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{
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type_ensure_zero_bits_known(ira->codegen, expected_type);
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if (expected_type->data.unionation.tag_type == actual_type) {
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return ImplicitCastMatchResultYes;
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}
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}
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// implicit undefined literal to anything
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if (actual_type->id == TypeTableEntryIdUndefLit) {
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return ImplicitCastMatchResultYes;
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@ -8370,6 +8381,63 @@ static IrInstruction *ir_analyze_undefined_to_anything(IrAnalyze *ira, IrInstruc
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return result;
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}
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static IrInstruction *ir_analyze_enum_to_union(IrAnalyze *ira, IrInstruction *source_instr,
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IrInstruction *target, TypeTableEntry *wanted_type)
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{
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assert(wanted_type->id == TypeTableEntryIdUnion);
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assert(target->value.type->id == TypeTableEntryIdEnum);
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if (instr_is_comptime(target)) {
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ConstExprValue *val = ir_resolve_const(ira, target, UndefBad);
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if (!val)
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return ira->codegen->invalid_instruction;
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TypeUnionField *union_field = find_union_field_by_tag(wanted_type, &val->data.x_enum_tag);
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assert(union_field != nullptr);
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type_ensure_zero_bits_known(ira->codegen, union_field->type_entry);
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if (!union_field->type_entry->zero_bits) {
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AstNode *field_node = wanted_type->data.unionation.decl_node->data.container_decl.fields.at(
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union_field->enum_field->decl_index);
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ErrorMsg *msg = ir_add_error(ira, source_instr,
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buf_sprintf("cast to union '%s' must initialize '%s' field '%s'",
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buf_ptr(&wanted_type->name),
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buf_ptr(&union_field->type_entry->name),
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buf_ptr(union_field->name)));
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add_error_note(ira->codegen, msg, field_node,
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buf_sprintf("field '%s' declared here", buf_ptr(union_field->name)));
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return ira->codegen->invalid_instruction;
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}
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IrInstruction *result = ir_create_const(&ira->new_irb, source_instr->scope,
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source_instr->source_node, wanted_type);
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result->value.special = ConstValSpecialStatic;
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result->value.type = wanted_type;
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bigint_init_bigint(&result->value.data.x_union.tag, &val->data.x_enum_tag);
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return result;
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}
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// if the union has all fields 0 bits, we can do it
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// and in fact it's a noop cast because the union value is just the enum value
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if (wanted_type->data.unionation.gen_field_count == 0) {
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IrInstruction *result = ir_build_cast(&ira->new_irb, target->scope, target->source_node, wanted_type, target, CastOpNoop);
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result->value.type = wanted_type;
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return result;
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}
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ErrorMsg *msg = ir_add_error(ira, source_instr,
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buf_sprintf("runtime cast to union '%s' which has non-void fields",
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buf_ptr(&wanted_type->name)));
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for (uint32_t i = 0; i < wanted_type->data.unionation.src_field_count; i += 1) {
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TypeUnionField *union_field = &wanted_type->data.unionation.fields[i];
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if (type_has_bits(union_field->type_entry)) {
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AstNode *field_node = wanted_type->data.unionation.decl_node->data.container_decl.fields.at(i);
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add_error_note(ira->codegen, msg, field_node,
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buf_sprintf("field '%s' has type '%s'",
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buf_ptr(union_field->name),
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buf_ptr(&union_field->type_entry->name)));
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}
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}
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return ira->codegen->invalid_instruction;
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}
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static IrInstruction *ir_analyze_widen_or_shorten(IrAnalyze *ira, IrInstruction *source_instr,
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IrInstruction *target, TypeTableEntry *wanted_type)
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{
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@ -8919,6 +8987,17 @@ static IrInstruction *ir_analyze_cast(IrAnalyze *ira, IrInstruction *source_inst
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}
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}
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// explicit enum to union which has the enum as the tag type
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if (wanted_type->id == TypeTableEntryIdUnion && actual_type->id == TypeTableEntryIdEnum &&
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(wanted_type->data.unionation.decl_node->data.container_decl.auto_enum ||
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wanted_type->data.unionation.decl_node->data.container_decl.init_arg_expr != nullptr))
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{
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type_ensure_zero_bits_known(ira->codegen, wanted_type);
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if (wanted_type->data.unionation.tag_type == actual_type) {
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return ir_analyze_enum_to_union(ira, source_instr, value, wanted_type);
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}
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}
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// explicit cast from undefined to anything
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if (actual_type->id == TypeTableEntryIdUndefLit) {
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return ir_analyze_undefined_to_anything(ira, source_instr, value, wanted_type);
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@ -190,3 +190,10 @@ test "cast union to tag type of union" {
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fn testCastUnionToTagType(x: &const TheUnion) {
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assert(TheTag(*x) == TheTag.B);
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}
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test "cast tag type of union to union" {
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var x: Value2 = Letter2.B;
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assert(Letter2(x) == Letter2.B);
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}
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const Letter2 = enum { A, B, C };
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const Value2 = union(Letter2) { A: i32, B, C, };
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@ -2696,4 +2696,35 @@ pub fn addCases(cases: &tests.CompileErrorContext) {
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,
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".tmp_source.zig:6:16: error: enum 'Foo' has no tag matching integer value 0",
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".tmp_source.zig:1:13: note: 'Foo' declared here");
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cases.add("comptime cast enum to union but field has payload",
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\\const Letter = enum { A, B, C };
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\\const Value = union(Letter) {
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\\ A: i32,
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\\ B,
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\\ C,
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\\};
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\\export fn entry() {
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\\ var x: Value = Letter.A;
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\\}
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,
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".tmp_source.zig:8:26: error: cast to union 'Value' must initialize 'i32' field 'A'",
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".tmp_source.zig:3:5: note: field 'A' declared here");
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cases.add("runtime cast to union which has non-void fields",
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\\const Letter = enum { A, B, C };
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\\const Value = union(Letter) {
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\\ A: i32,
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\\ B,
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\\ C,
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\\};
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\\export fn entry() {
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\\ foo(Letter.A);
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\\}
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\\fn foo(l: Letter) {
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\\ var x: Value = l;
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\\}
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,
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".tmp_source.zig:11:20: error: runtime cast to union 'Value' which has non-void fields",
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".tmp_source.zig:3:5: note: field 'A' has type 'i32'");
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}
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