test: cover qualified function calls with three segments

mdl-examples/bug-tests/qualified-function-call-expression.mdl

@@ -0,0 +1,31 @@
+-- ============================================================================
+-- Regression: Qualified function calls in microflow expressions
+-- ============================================================================
+--
+-- Symptom:
+--   Qualified function/microflow-style calls used as IF conditions failed to
+--   parse when the expression callee was not a built-in function name.
+--
+-- After fix:
+--   The expression grammar accepts qualified names as function call targets,
+--   including three-segment names emitted by describe for rule-like split
+--   conditions.
+--
+-- Usage:
+--   mxcli check mdl-examples/bug-tests/qualified-function-call-expression.mdl
+-- ============================================================================
+
+create module SyntheticQualifiedCall;
+
+create microflow SyntheticQualifiedCall.MF_QualifiedCall (
+  $S: string
+)
+returns boolean as $Result
+begin
+  if SyntheticRules.Strings.IsNotEmpty(String = $S) then
+    return true;
+  else
+    return false;
+  end if;
+end;
+/

mdl/visitor/visitor_qualified_call_test.go

@@ -15,9 +15,9 @@ import (
 // failed to parse with `mismatched input '(' expecting THEN`, blocking the
 // roundtrip for microflows whose ExclusiveSplit uses a RuleSplitCondition.
 func TestQualifiedCallInIfCondition(t *testing.T) {
-	input := `CREATE OR MODIFY MICROFLOW MxAdmin.Test ($S: String) returns Boolean
+	input := `CREATE OR MODIFY MICROFLOW SyntheticQualifiedCall.Test ($S: String) returns Boolean
 BEGIN
-  IF ControlCenterCommons.IsNotEmptyString(String = $S) THEN
+  IF SyntheticRules.Strings.IsNotEmpty(String = $S) THEN
     RETURN true;
   ELSE
     RETURN false;
@@ -45,8 +45,8 @@ END`
 	if !ok {
 		t.Fatalf("expected FunctionCallExpr as if-condition, got %T", ifStmt.Condition)
 	}
-	if call.Name != "ControlCenterCommons.IsNotEmptyString" {
-		t.Errorf("call name = %q, want %q", call.Name, "ControlCenterCommons.IsNotEmptyString")
+	if call.Name != "SyntheticRules.Strings.IsNotEmpty" {
+		t.Errorf("call name = %q, want %q", call.Name, "SyntheticRules.Strings.IsNotEmpty")
 	}
 	if len(call.Arguments) != 1 {
 		t.Fatalf("expected 1 argument, got %d", len(call.Arguments))