Commit 44f8e6a534bd2977c741afdbf5ba9df49bde0fd9 | zig

author	LemonBoy <thatlemon@gmail.com> 2020-10-21 15:35:40+02:00
committer	Andrew Kelley <andrew@ziglang.org> 2020-10-21 22:42:03-04:00
log	44f8e6a534bd2977c741afdbf5ba9df49bde0fd9
tree	2d7274179977704d5bd24074b6f9306518da14de
parent	52879b50d9fe221c46e62e11c6815da64c70638e

stage1: Fix edge case in Union ZigValue generation

Unions that passed the one_possible_value check were incorrectly
generated, none of their internal fields were initialized.

Fixes #6758

2 files changed, 39 insertions(+), 1 deletions(-)

src
- stage1
  - analyze.cpp
test
- stage1
  - behavior
    union.zig

src/stage1/analyze.cpp+15-1

...	...	@@ -5973,7 +5973,8 @@ ZigValue get_the_one_possible_value(CodeGen g, ZigType *type_entry) {
5973	5973	}
5974	5974	ZigType *field_type = resolve_struct_field_type(g, field);
5975	5975	assert(field_type != nullptr);
5976		result->data.x_struct.fields[i] = get_the_one_possible_value(g, field_type);
	5976	copy_const_val(g, result->data.x_struct.fields[i],
	5977	get_the_one_possible_value(g, field_type));
5977	5978	}
5978	5979	} else if (result->type->id == ZigTypeIdArray) {
5979	5980	// The elements array cannot be left unpopulated
...	...	@@ -5986,7 +5987,20 @@ ZigValue get_the_one_possible_value(CodeGen g, ZigType *type_entry) {
5986	5987	ZigValue *elem_val = &result->data.x_array.data.s_none.elements[i];
5987	5988	copy_const_val(g, elem_val, get_the_one_possible_value(g, elem_type));
5988	5989	}
	5990	} else if (result->type->id == ZigTypeIdUnion) {
	5991	// The payload/tag fields cannot be left unpopulated
	5992	ZigType *union_type = result->type;
	5993	assert(union_type->data.unionation.src_field_count == 1);
	5994	TypeUnionField *only_field = &union_type->data.unionation.fields[0];
	5995	ZigType *field_type = resolve_union_field_type(g, only_field);
	5996	assert(field_type);
	5997	bigint_init_unsigned(&result->data.x_union.tag, 0);
	5998	result->data.x_union.payload = g->pass1_arena->create<ZigValue>();
	5999	copy_const_val(g, result->data.x_union.payload,
	6000	get_the_one_possible_value(g, field_type));
5989	6001	} else if (result->type->id == ZigTypeIdPointer) {
	6002	// Make sure nobody can modify the constant value
	6003	result->data.x_ptr.mut = ConstPtrMutComptimeConst;
5990	6004	result->data.x_ptr.special = ConstPtrSpecialRef;
5991	6005	result->data.x_ptr.data.ref.pointee = get_the_one_possible_value(g, result->type->data.pointer.child_type);
5992	6006	}

test/stage1/behavior/union.zig+24

...	...	@@ -713,3 +713,27 @@ test "switching on non exhaustive union" {
713	713	S.doTheTest();
714	714	comptime S.doTheTest();
715	715	}
	716
	717	test "containers with single-field enums" {
	718	const S = struct {
	719	const A = union(enum) { f1 };
	720	const B = union(enum) { f1: void };
	721	const C = struct { a: A };
	722	const D = struct { a: B };
	723
	724	fn doTheTest() void {
	725	var array1 = [1]A{A{ .f1 = {} }};
	726	var array2 = [1]B{B{ .f1 = {} }};
	727	expect(array1[0] == .f1);
	728	expect(array2[0] == .f1);
	729
	730	var struct1 = C{ .a = A{ .f1 = {} } };
	731	var struct2 = D{ .a = B{ .f1 = {} } };
	732	expect(struct1.a == .f1);
	733	expect(struct2.a == .f1);
	734	}
	735	};
	736
	737	S.doTheTest();
	738	comptime S.doTheTest();
	739	}