From ebed9316c50b20e12631124d568bf9de8a8b6c11 Mon Sep 17 00:00:00 2001
From: Jacob Young <jacobly@ziglang.org>
Date: Tue, 6 Oct 2026 07:51:24 -0400
Subject: [PATCH] Type: fix vector size mismatch vs clang

This operation used to be implied by the old incorrect alignment
calculation, but seems to apply even when the alignment is saturated.

Closes #37110
---
 src/Type.zig            | 5 ++++-
 test/behavior/error.zig | 6 ++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/Type.zig b/src/Type.zig
index b7312967fd3ea85bd1f0f20062649a7ff5a53bfa..2c207738b8f55cae37a5a120b68d968fa51e1f66 100644
--- a/src/Type.zig
+++ b/src/Type.zig
@@ -1151,7 +1151,10 @@ pub fn abiSize(ty: Type, zcu: *const Zcu) u64 {
                     std.zig.target.compilerRtFloatAbi(target, elem_ty.floatBits(target))
                 else
                     .hard) {
-                    .hard => @divCeil(vec.len * elem_ty.bitSize(zcu), 8),
+                    .hard => switch (vec.len * elem_ty.bitSize(zcu)) {
+                        0 => return 0,
+                        else => |bits| std.math.ceilPowerOfTwoAssert(u32, @intCast(@divCeil(bits, 8))),
+                    },
                     .soft => vec.len * elem_ty.abiSize(zcu),
                 },
                 .stage2_c, .stage2_wasm => vec.len * elem_ty.abiSize(zcu),
diff --git a/test/behavior/error.zig b/test/behavior/error.zig
index 46f7871a8281f76841f15f85b8d78f9f3db9f6bf..132193c85b777beabe63fad397d92d8d8e03918a 100644
--- a/test/behavior/error.zig
+++ b/test/behavior/error.zig
@@ -1138,3 +1138,9 @@ test "@errorCast into other inferred error set" {
     const non_err: Ies!u32 = @errorCast(@as(error{}!u32, 123));
     try expect(try non_err == 123);
 }
+
+test "error union with vector type" {
+    var x: anyerror!@Vector(5, f64) = undefined;
+    x = error.Expected;
+    try expect(x == error.Expected);
+}
-- 
2.54.0