Crash during codegen when taking the typeid of an empty enum with associated values.

releasenotes.md

@@ -39,6 +39,7 @@
 - Alias and distinct types didn't check the underlying type wasn't compile time or optional.
 - Incorrect nameof on nested struct names. #2492
 - Issue not correctly aborting compilation on recursive generics.
+- Crash during codegen when taking the typeid of an empty enum with associated values.
 
 ### Stdlib changes
 - Added generic `InterfaceList` to store a list of values that implement a specific interface

src/compiler/llvm_codegen_type.c

@@ -557,6 +557,7 @@ static LLVMValueRef llvm_get_introspection_for_enum(GenContext *c, Type *type)
 			if (val_type != LLVMTypeOf(llvm_value)) mixed = true;
 		}
 		Decl *associated_value = associated_values[ai];
+		if (!val_type)val_type = llvm_get_type(c, associated_value->type);
 		LLVMValueRef associated_value_arr = mixed ? llvm_get_packed_struct(c, values, elements)
 				: llvm_get_array(val_type, values, elements);
 		scratch_buffer_set_extern_decl_name(decl, true);

test/test_suite/enumerations/enum_empty_typeid.c3t

@@ -0,0 +1,27 @@
+// #target: macos-x64
+module test;
+
+enum No_Els_Assoc : (any anything)
+{}
+
+macro typeid @segfault () => No_Els_Assoc.typeid;
+
+fn int main ()
+{
+    typeid x = @segfault();
+    return 0;
+}
+
+/* #expect: test.ll
+
+@"$ct.int" = linkonce global %.introspect { i8 2, i64 0, ptr null, i64 4, i64 0, i64 0, [0 x i64] zeroinitializer }, align 8
+@"$ct.test.No_Els_Assoc" = linkonce global { i8, i64, ptr, i64, i64, i64, [0 x %"char[]"] } { i8 8, i64 0, ptr null, i64 4, i64 ptrtoint (ptr @"$ct.int" to i64), i64 0, [0 x %"char[]"] zeroinitializer }, align 8
+@"test.No_Els_Assoc$anything" = linkonce constant [0 x %any] zeroinitializer, align 8
+
+; Function Attrs: nounwind uwtable
+define i32 @main() #0 {
+entry:
+  %x = alloca i64, align 8
+  store i64 ptrtoint (ptr @"$ct.test.No_Els_Assoc" to i64), ptr %x, align 8
+  ret i32 0
+}