diff --git a/tools/qfcc/include/target.h b/tools/qfcc/include/target.h
index 7d850d4ce..3b12077a0 100644
--- a/tools/qfcc/include/target.h
+++ b/tools/qfcc/include/target.h
@@ -56,8 +56,11 @@ typedef struct {
 	const expr_t *(*vector_compare)(int op, const expr_t *e1, const expr_t *e2);
 	const expr_t *(*shift_op)(int op, const expr_t *e1, const expr_t *e2);
 	const expr_t *(*test_expr) (const expr_t *expr);
+	const expr_t *(*cast_expr) (const type_t *dstType, const expr_t *expr);
 	const expr_t *(*check_types_compatible) (const expr_t *dst,
 											 const expr_t *src);
+	bool      (*type_assignable) (const type_t *dst, const type_t *src);
+	bool      (*init_type_ok) (const type_t *dst, const type_t *src);
 
 	bool      (*setup_intrinsic_symtab) (symtab_t *symtab);
 
diff --git a/tools/qfcc/source/expr_cast.c b/tools/qfcc/source/expr_cast.c
index 3a99c4b5b..94dadabd0 100644
--- a/tools/qfcc/source/expr_cast.c
+++ b/tools/qfcc/source/expr_cast.c
@@ -42,6 +42,7 @@
 #include "tools/qfcc/include/diagnostic.h"
 #include "tools/qfcc/include/expr.h"
 #include "tools/qfcc/include/struct.h"
+#include "tools/qfcc/include/target.h"
 #include "tools/qfcc/include/type.h"
 #include "tools/qfcc/include/value.h"
 
@@ -148,6 +149,12 @@ cast_expr (const type_t *dstType, const expr_t *e)
 			 && (is_short (srcType) || is_ushort (srcType))
 			 // [u]short is always width 0
 			 && type_width (dstType) == 1)) {
+		if (current_target.cast_expr) {
+			auto c = current_target.cast_expr (dstType, e);
+			if (c) {
+				return c;
+			}
+		}
 		return cast_error (e, srcType, dstType);
 	}
 	if (is_array (srcType)) {
diff --git a/tools/qfcc/source/function.c b/tools/qfcc/source/function.c
index 45feec6d9..57397671f 100644
--- a/tools/qfcc/source/function.c
+++ b/tools/qfcc/source/function.c
@@ -685,8 +685,12 @@ check_type (const type_t *type, callparm_t param, unsigned *cost, bool promote)
 		bool demotes = param.implicit && type_demotes (type, param.type);
 		if (demotes) {
 			*cost += 1;
+			return true;
+		}
+		// allow any final checks
+		if (!type_assignable (type, param.type)) {
+			return false;
 		}
-		return demotes;
 	}
 	*cost += 2;
 	return true;
diff --git a/tools/qfcc/source/stub.c b/tools/qfcc/source/stub.c
index 0a8fb9ab0..47dcb0f32 100644
--- a/tools/qfcc/source/stub.c
+++ b/tools/qfcc/source/stub.c
@@ -21,9 +21,11 @@
 #include "tools/qfcc/include/strpool.h"
 #include "tools/qfcc/include/struct.h"
 #include "tools/qfcc/include/symtab.h"
+#include "tools/qfcc/include/target.h"
 #include "tools/qfcc/include/type.h"
 #include "tools/qfcc/include/value.h"
 
+target_t current_target;
 struct dstring_s;
 options_t options;
 int num_linenos;
diff --git a/tools/qfcc/source/symtab.c b/tools/qfcc/source/symtab.c
index 9b77c41c7..c3c99eaf5 100644
--- a/tools/qfcc/source/symtab.c
+++ b/tools/qfcc/source/symtab.c
@@ -295,6 +295,10 @@ init_type_ok (const type_t *dstType, const expr_t *init)
 		&& (type_size (dstType) == type_size (init_type))) {
 		return true;
 	}
+	if (current_target.init_type_ok
+		&& current_target.init_type_ok (dstType, init_type)) {
+		return true;
+	}
 	return false;
 }
 
diff --git a/tools/qfcc/source/target_spirv.c b/tools/qfcc/source/target_spirv.c
index 8df004d6f..1873eee69 100644
--- a/tools/qfcc/source/target_spirv.c
+++ b/tools/qfcc/source/target_spirv.c
@@ -2682,6 +2682,18 @@ spirv_types_logically_match (const type_t *dst, const type_t *src)
 	return false;
 }
 
+static const expr_t *
+spirv_cast_expr (const type_t *dstType, const expr_t *expr)
+{
+	auto src_type = get_type (expr);
+	if (!spirv_types_logically_match (dstType, src_type)) {
+		return nullptr;
+	}
+	auto cast = new_unary_expr ('C', expr);
+	cast->expr.type = dstType;
+	return cast;
+}
+
 static const expr_t *
 spirv_check_types_compatible (const expr_t *dst, const expr_t *src)
 {
@@ -2691,8 +2703,7 @@ spirv_check_types_compatible (const expr_t *dst, const expr_t *src)
 	if (!spirv_types_logically_match (dst_type, src_type)) {
 		return nullptr;
 	}
-	auto cast = new_unary_expr ('C', src);
-	cast->expr.type = dst_type;
+	auto cast = spirv_cast_expr (dst_type, src);
 	return assign_expr (dst, cast);
 }
 
@@ -2718,5 +2729,8 @@ target_t spirv_target = {
 	// ruamoko and spirv are mostly compatible for bools other than lbool
 	// but that's handled by spirv_mirror_bool
 	.test_expr = ruamoko_test_expr,
+	.cast_expr = spirv_cast_expr,
 	.check_types_compatible = spirv_check_types_compatible,
+	.type_assignable = spirv_types_logically_match,
+	.init_type_ok = spirv_types_logically_match,
 };
diff --git a/tools/qfcc/source/type.c b/tools/qfcc/source/type.c
index 5a349b479..84905e7b2 100644
--- a/tools/qfcc/source/type.c
+++ b/tools/qfcc/source/type.c
@@ -60,6 +60,7 @@
 #include "tools/qfcc/include/strpool.h"
 #include "tools/qfcc/include/struct.h"
 #include "tools/qfcc/include/symtab.h"
+#include "tools/qfcc/include/target.h"
 #include "tools/qfcc/include/type.h"
 
 #define EV_TYPE(t) \
@@ -1752,6 +1753,9 @@ type_assignable (const type_t *dst, const type_t *src)
 		if (is_lbool (dst) && is_bool (src)) {
 			return true;
 		}
+		if (current_target.type_assignable) {
+			return current_target.type_assignable (dst, src);
+		}
 		return false;
 	}