genbindings: call correct c++ function for optional parameters

cmd/genbindings/emitcabi.go

@@ -235,6 +235,11 @@ func emitBindingCpp(src *CppParsedHeader, filename string) (string, error) {
 
 			preamble, forwarding := emitParametersCABI2CppForwarding(m.Parameters)
 
+			nativeMethodName := m.MethodName
+			if m.OverrideMethodName != "" {
+				nativeMethodName = m.OverrideMethodName
+			}
+
 			ret.WriteString(fmt.Sprintf(
 				"%s %s_%s(%s) {\n"+
 					"%s"+
@@ -244,7 +249,7 @@ func emitBindingCpp(src *CppParsedHeader, filename string) (string, error) {
 					"\n",
 				emitReturnTypeCabi(m.ReturnType), c.ClassName, m.SafeMethodName(), emitParametersCabi(m, "P"+c.ClassName),
 				preamble,
-				shouldReturn, c.ClassName, m.MethodName, forwarding,
+				shouldReturn, c.ClassName, nativeMethodName, forwarding,
 				afterCall,
 			))
 		}

cmd/genbindings/intermediate.go

@@ -24,9 +24,10 @@ type CppProperty struct {
 }
 
 type CppMethod struct {
-	MethodName string
-	ReturnType CppParameter // Name not used
-	Parameters []CppParameter
+	MethodName         string
+	OverrideMethodName string       // Present only if we changed the target
+	ReturnType         CppParameter // Name not used
+	Parameters         []CppParameter
 }
 
 func (nm CppMethod) SafeMethodName() string {

cmd/genbindings/transformoptional.go

@@ -29,9 +29,10 @@ func astTransformOptional(parsed *CppParsedHeader) {
 			// Add method copies
 			for x := optionalStart; x < len(m.Parameters); x++ {
 				dupMethod := CppMethod{
-					MethodName: m.MethodName + fmt.Sprintf("%d", x+1),
-					ReturnType: m.ReturnType,
-					Parameters: nil,
+					MethodName:         m.MethodName + fmt.Sprintf("%d", x+1),
+					OverrideMethodName: m.MethodName,
+					ReturnType:         m.ReturnType,
+					Parameters:         nil,
 				}
 				dupMethod.Parameters = append(dupMethod.Parameters, m.Parameters[0:x+1]...)
 				c.Methods = append(c.Methods, dupMethod) // TODO can we insert them next, instead of at the end?