Add intrinsics.type_is_variant_of

core/intrinsics/intrinsics.odin

@@ -159,6 +159,7 @@ type_is_simd_vector      :: proc($T: typeid) -> bool ---
 type_has_nil :: proc($T: typeid) -> bool ---
 
 type_is_specialization_of :: proc($T, $S: typeid) -> bool ---
+type_is_variant_of :: proc($U, $V: typeid) -> bool where type_is_union(U) ---
 
 type_has_field :: proc($T: typeid, $name: string) -> bool ---
 

src/check_builtin.cpp

@@ -2429,6 +2429,46 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 		}
 		break;
 
+	case BuiltinProc_type_is_variant_of:
+		{
+			if (operand->mode != Addressing_Type) {
+				error(operand->expr, "Expected a type for '%.*s'", LIT(builtin_name));
+				operand->mode = Addressing_Invalid;
+				operand->type = t_invalid;
+				return false;
+			}
+
+
+			Type *u = operand->type;
+
+			if (!is_type_union(u)) {
+				error(operand->expr, "Expected a union type for '%.*s'", LIT(builtin_name));
+				operand->mode = Addressing_Invalid;
+				operand->type = t_invalid;
+				return false;
+			}
+
+			Type *v = check_type(c, ce->args[1]);
+
+			u = base_type(u);
+			GB_ASSERT(u->kind == Type_Union);
+
+			bool is_variant = false;
+
+			for_array(i, u->Union.variants) {
+				Type *vt = u->Union.variants[i];
+				if (are_types_identical(v, vt)) {
+					is_variant = true;
+					break;
+				}
+			}
+
+			operand->mode = Addressing_Constant;
+			operand->type = t_untyped_bool;
+			operand->value = exact_value_bool(is_variant);
+		}
+		break;
+
 	case BuiltinProc_type_struct_field_count:
 		operand->value = exact_value_i64(0);
 		if (operand->mode != Addressing_Type) {

src/checker_builtin_procs.hpp

@@ -197,6 +197,8 @@ BuiltinProc__type_simple_boolean_end,
 
 	BuiltinProc_type_is_specialization_of,
 
+	BuiltinProc_type_is_variant_of,
+
 	BuiltinProc_type_struct_field_count,
 
 	BuiltinProc_type_proc_parameter_count,
@@ -415,6 +417,8 @@ gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
 
 	{STR_LIT("type_is_specialization_of"), 2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 
+	{STR_LIT("type_is_variant_of"), 2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
 	{STR_LIT("type_struct_field_count"),   1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 
 	{STR_LIT("type_proc_parameter_count"), 1, false, Expr_Expr, BuiltinProcPkg_intrinsics},