diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index 6a9a53275..7c4c4e6e4 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -3214,6 +3214,7 @@ BuiltinTypeIsProc *builtin_type_is_procs[BuiltinProc__type_end - BuiltinProc__ty
 	is_type_rune,
 	is_type_float,
 	is_type_complex,
+	is_type_quaternion,
 	is_type_string,
 	is_type_typeid,
 	is_type_any,
@@ -4776,6 +4777,7 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 	case BuiltinProc_type_is_rune:
 	case BuiltinProc_type_is_float:
 	case BuiltinProc_type_is_complex:
+	case BuiltinProc_type_is_quaternion:
 	case BuiltinProc_type_is_string:
 	case BuiltinProc_type_is_typeid:
 	case BuiltinProc_type_is_any:
diff --git a/src/checker_builtin_procs.hpp b/src/checker_builtin_procs.hpp
index 0135b3c50..b119452d4 100644
--- a/src/checker_builtin_procs.hpp
+++ b/src/checker_builtin_procs.hpp
@@ -120,6 +120,7 @@ BuiltinProc__type_begin,
 	BuiltinProc_type_is_rune,
 	BuiltinProc_type_is_float,
 	BuiltinProc_type_is_complex,
+	BuiltinProc_type_is_quaternion,
 	BuiltinProc_type_is_string,
 	BuiltinProc_type_is_typeid,
 	BuiltinProc_type_is_any,
@@ -278,6 +279,7 @@ gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
 	{STR_LIT("type_is_rune"),              1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("type_is_float"),             1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("type_is_complex"),           1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+	{STR_LIT("type_is_quaternion"),        1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("type_is_string"),            1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("type_is_typeid"),            1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("type_is_any"),               1, false, Expr_Expr, BuiltinProcPkg_intrinsics},