Commit e6b73be870a39f4da7a08a40da23e38b5e9613da | zig

author	Andrew Kelley <andrew@ziglang.org> 2023-10-12 21:54:59-07:00
committer	Andrew Kelley <andrew@ziglang.org> 2023-10-12 22:03:39-07:00
log	e6b73be870a39f4da7a08a40da23e38b5e9613da
tree	b21b81ecc4867273bf864988a8d63bb27b12b6c2
parent	2769215b9037bb1f407e07887d4d21957ce1a9e0

Sema: fix crash when coercion dest is var args

When analyzing the `as` ZIR instruction, an assertion would trip if the
result type was a var args function argument. The fix is simple: inline
a little bit of the `resolveType` logic into `analyzeAs` to make it
detect this situation - which it was already attempting to do.

Closes #16197

2 files changed, 19 insertions(+), 2 deletions(-)

src
- Sema.zig
test
- behavior
  - var_args.zig

src/Sema.zig+10-2

 @@ -9846,11 +9846,19 @@ fn analyzeAs(
     const mod = sema.mod;
     const operand = try sema.resolveInst(zir_operand);
     if (zir_dest_type == .var_args_param_type) return operand;
-    const dest_ty = sema.resolveType(block, src, zir_dest_type) catch |err| switch (err) {
+    const operand_air_inst = sema.resolveInst(zir_dest_type) catch |err| switch (err) {
         error.GenericPoison => return operand,
         else => |e| return e,
     };
-    if (dest_ty.zigTypeTag(mod) == .NoReturn) {
+    if (operand_air_inst == .var_args_param_type) return operand;
+    const dest_ty = sema.analyzeAsType(block, src, operand_air_inst) catch |err| switch (err) {
+        error.GenericPoison => return operand,
+        else => |e| return e,
+    };
+    const dest_ty_tag = dest_ty.zigTypeTagOrPoison(mod) catch |err| switch (err) {
+        error.GenericPoison => return operand,
+    };
+    if (dest_ty_tag == .NoReturn) {
         return sema.fail(block, src, "cannot cast to noreturn", .{});
     }
     const is_ret = if (Zir.refToIndex(zir_dest_type)) |ptr_index|

test/behavior/var_args.zig+9

...	@@ -150,6 +150,15 @@ test "simple variadic function" {	...	@@ -150,6 +150,15 @@ test "simple variadic function" {
150	try std.testing.expectEqual(@as(c_int, 0), S.add(0));	150	try std.testing.expectEqual(@as(c_int, 0), S.add(0));
151	try std.testing.expectEqual(@as(c_int, 1), S.add(1, @as(c_int, 1)));	151	try std.testing.expectEqual(@as(c_int, 1), S.add(1, @as(c_int, 1)));
152	try std.testing.expectEqual(@as(c_int, 3), S.add(2, @as(c_int, 1), @as(c_int, 2)));	152	try std.testing.expectEqual(@as(c_int, 3), S.add(2, @as(c_int, 1), @as(c_int, 2)));
		153
		154	{
		155	// Test type coercion of a var args argument.
		156	// Originally reported at https://github.com/ziglang/zig/issues/16197
		157	var runtime: bool = true;
		158	var a: i32 = 1;
		159	var b: i32 = 2;
		160	try expect(1 == S.add(1, if (runtime) a else b));
		161	}
153	}	162	}
154		163
155	test "variadic functions" {	164	test "variadic functions" {