User defined attributes.

test/test_suite/attributes/recursive_attributes.c3

@@ -0,0 +1,17 @@
+module test;
+
+define @Align(y) = @Align16(y / 2);
+define @Align16(x) = @align(4), @Align(8 * x); // #error: Recursive declaration of attribute
+define @Test = @noinline;
+struct Foo
+{
+	int z;
+	int xy @Align16(8);
+}
+
+Foo f;
+
+fn void testme() @Test
+{
+	int x;
+}

test/test_suite/attributes/repeat_of_attributes.c3

@@ -1,6 +0,0 @@
-fn void test()
-{
-    for (int a @align(16) @align(16) = 0 ; a < 10; a++) // #error: Repeat of attribute '@align'
-    {
-    }
-}

test/test_suite/attributes/user_defined_attributes.c3t

@@ -0,0 +1,45 @@
+// #target: macos-x64
+
+module test;
+
+define @Align(y) = @align(y);
+define @Align16(x) = @Align(8 * x), @align(1024);
+define @Test = @noinline;
+define @TestZero;
+struct Foo
+{
+	int z;
+	int xy @Align16(8);
+}
+
+Foo f;
+
+fn void testme() @Test
+{
+	int x;
+}
+
+fn void main() @TestZero
+{
+	testme();
+}
+
+/* #expect: test.ll
+
+%Foo = type { i32, [1020 x i8], i32, [1020 x i8] }
+
+@introspect.Foo = linkonce constant i8 1
+@test.f = local_unnamed_addr global %Foo zeroinitializer, align 1024
+
+define void @test.testme() #0 {
+entry:
+  %x = alloca i32, align 4
+  store i32 0, i32* %x, align 4
+  ret void
+}
+
+define void @test.main() #1 {
+entry:
+  call void @test.testme()
+  ret void
+}