diff --git a/astgen.c b/astgen.c
index d09aa09c64..288b2ac01c 100644
--- a/astgen.c
+++ b/astgen.c
@@ -2668,7 +2668,8 @@ static uint32_t tryResolvePrimitiveIdent(GenZir* gz, uint32_t node) {
     // Integer type detection: u29, i13, etc. (AstGen.zig:8304-8336).
     if (tok_len >= 2
         && (source[tok_start] == 'u' || source[tok_start] == 'i')) {
-        uint8_t signedness = (source[tok_start] == 'i') ? 1 : 0;
+        // Zig Signedness enum: unsigned=1, signed=0
+        uint8_t signedness = (source[tok_start] == 'u') ? 1 : 0;
         uint16_t bit_count = 0;
         bool valid = true;
         for (uint32_t k = tok_start + 1; k < tok_end; k++) {
diff --git a/astgen_test.zig b/astgen_test.zig
index 1cd940b43f..5592d1fc32 100644
--- a/astgen_test.zig
+++ b/astgen_test.zig
@@ -798,8 +798,8 @@ test "astgen: corpus tokenizer_test.zig" {
 }
 
 test "astgen: corpus parser_test.zig" {
-    // TODO: int_type signedness data mismatch at inst[6899] — all tags and
-    // inst_len match, but one int_type has ref=signed got=unsigned.
+    // TODO: 10+ extra data mismatches (ref=48 got=32, bit 4 = propagate_error_trace)
+    // in call instruction flags — ctx propagation differs from upstream.
     if (true) return error.SkipZigTest;
     const gpa = std.testing.allocator;
     try corpusCheck(gpa, @embedFile("parser_test.zig"));
diff --git a/zir.h b/zir.h
index 766d66938c..10950e1249 100644
--- a/zir.h
+++ b/zir.h
@@ -384,9 +384,9 @@ typedef union {
     } ptr_type;
     struct {
         int32_t src_node;
+        uint16_t bit_count;
         uint8_t signedness;
         uint8_t _pad;
-        uint16_t bit_count;
     } int_type;
     struct {
         int32_t src_node;