stage2: fix 0-bit function parameters

Before this commit, Zig would incorrectly emit `arg` AIR instructions
for parameters whose types were 0-bit.

1 files changed, 32 insertions, 0 deletions

diff --git a/test/behavior/enum_llvm.zig b/test/behavior/enum_llvm.zig
index c0d536c029..700e396087 100644
--- a/test/behavior/enum_llvm.zig
+++ b/test/behavior/enum_llvm.zig
@@ -90,3 +90,35 @@ fn getB(data: *const BitFieldOfEnums) B {
 fn getC(data: *const BitFieldOfEnums) C {
     return data.c;
 }
+
+const EnumWithOneMember = enum { Eof };
+
+fn doALoopThing(id: EnumWithOneMember) void {
+    while (true) {
+        if (id == EnumWithOneMember.Eof) {
+            break;
+        }
+        @compileError("above if condition should be comptime");
+    }
+}
+
+test "comparison operator on enum with one member is comptime known" {
+    doALoopThing(EnumWithOneMember.Eof);
+}
+
+const State = enum { Start };
+test "switch on enum with one member is comptime known" {
+    var state = State.Start;
+    switch (state) {
+        State.Start => return,
+    }
+    @compileError("analysis should not reach here");
+}
+
+test "enum literal in array literal" {
+    const Items = enum { one, two };
+    const array = [_]Items{ .one, .two };
+
+    try expect(array[0] == .one);
+    try expect(array[1] == .two);
+}