fix [x]u65529 and above overflowing

src/type.zig

@@ -3596,12 +3596,12 @@ pub const Type = extern union {
 
     fn intAbiSize(bits: u16, target: Target) u64 {
         const alignment = intAbiAlignment(bits, target);
-        return std.mem.alignForwardGeneric(u64, (bits + 7) / 8, alignment);
+        return std.mem.alignForwardGeneric(u64, @intCast(u16, (@as(u17, bits) + 7) / 8), alignment);
     }
 
     fn intAbiAlignment(bits: u16, target: Target) u32 {
         return @min(
-            std.math.ceilPowerOfTwoPromote(u16, (bits + 7) / 8),
+            std.math.ceilPowerOfTwoPromote(u16, @intCast(u16, (@as(u17, bits) + 7) / 8)),
             target.maxIntAlignment(),
         );
     }

test/behavior/basic.zig

@@ -1124,3 +1124,24 @@ test "runtime-known globals initialized with undefined" {
     try expect(S.s[0] == 1);
     try expect(S.s[4] == 5);
 }
+
+test "arrays and vectors with big integers" {
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest;
+
+    // TODO: only aarch64-windows didn't pass in the PR that added this code.
+    //       figure out why if you can run this target.
+    if (builtin.os.tag == .windows and builtin.cpu.arch == .aarch64) return error.SkipZigTest;
+
+    inline for (.{ u65528, u65529, u65535 }) |Int| {
+        var a: [1]Int = undefined;
+        a[0] = std.math.maxInt(Int);
+        try expect(a[0] == comptime std.math.maxInt(Int));
+        var b: @Vector(1, Int) = undefined;
+        b[0] = std.math.maxInt(Int);
+        try expect(b[0] == comptime std.math.maxInt(Int));
+    }
+}