packed structs can have enums with explicit tag types

See #305

2 files changed, 11 insertions, 2 deletions

diff --git a/src/analyze.cpp b/src/analyze.cpp
index 33d6ccdc39..235aeea682 100644
--- a/src/analyze.cpp
+++ b/src/analyze.cpp
@@ -1536,7 +1536,6 @@ static bool type_allowed_in_packed_struct(TypeTableEntry *type_entry) {
         case TypeTableEntryIdNullLit:
         case TypeTableEntryIdErrorUnion:
         case TypeTableEntryIdPureError:
-        case TypeTableEntryIdEnum:
         case TypeTableEntryIdEnumTag:
         case TypeTableEntryIdNamespace:
         case TypeTableEntryIdBlock:
@@ -1560,6 +1559,9 @@ static bool type_allowed_in_packed_struct(TypeTableEntry *type_entry) {
                 TypeTableEntry *child_type = type_entry->data.maybe.child_type;
                 return child_type->id == TypeTableEntryIdPointer || child_type->id == TypeTableEntryIdFn;
             }
+        case TypeTableEntryIdEnum:
+            return type_entry->data.enumeration.gen_field_count == 0 &&
+                type_entry->data.enumeration.decl_node->data.container_decl.init_arg_expr != nullptr;
     }
     zig_unreachable();
 }
diff --git a/src/codegen.cpp b/src/codegen.cpp
index da94dd4bcd..a5f8b85e22 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -3762,7 +3762,6 @@ static LLVMValueRef pack_const_int(CodeGen *g, LLVMTypeRef big_int_type_ref, Con
         case TypeTableEntryIdNullLit:
         case TypeTableEntryIdErrorUnion:
         case TypeTableEntryIdPureError:
-        case TypeTableEntryIdEnum:
         case TypeTableEntryIdEnumTag:
         case TypeTableEntryIdNamespace:
         case TypeTableEntryIdBlock:
@@ -3773,6 +3772,13 @@ static LLVMValueRef pack_const_int(CodeGen *g, LLVMTypeRef big_int_type_ref, Con
             zig_unreachable();
         case TypeTableEntryIdBool:
             return LLVMConstInt(big_int_type_ref, const_val->data.x_bool ? 1 : 0, false);
+        case TypeTableEntryIdEnum:
+            {
+                assert(type_entry->data.enumeration.gen_field_count == 0);
+                assert(type_entry->data.enumeration.decl_node->data.container_decl.init_arg_expr != nullptr);
+                LLVMValueRef int_val = gen_const_val(g, const_val);
+                return LLVMConstZExt(int_val, big_int_type_ref);
+            }
         case TypeTableEntryIdInt:
             {
                 LLVMValueRef int_val = gen_const_val(g, const_val);
@@ -3814,6 +3820,7 @@ static LLVMValueRef pack_const_int(CodeGen *g, LLVMTypeRef big_int_type_ref, Con
                 }
                 return val;
             }
+
     }
     zig_unreachable();
 }