GROOVY-11888: STC: method resolution fails for UnionTypeClassNode due to premature covariant elimination

Author: paulk-asert

src/main/java/org/codehaus/groovy/transform/stc/StaticTypeCheckingSupport.java

@@ -953,20 +953,21 @@ public static List<MethodNode> chooseBestMethod(final ClassNode receiver, Collec
 
         // GROOVY-8965: type disjunction
         boolean duckType = receiver instanceof UnionTypeClassNode;
-        if (!duckType && methods.size() > 1 && !first(methods).isConstructor())
-            methods = removeCovariantsAndInterfaceEquivalents(methods, false);
-
-        if (!duckType && argumentTypes == null) {
-            return asList(methods); // GROOVY-11683: no covariants or equivalents
+        if (!duckType) {
+            if (methods.size() > 1 && !first(methods).isConstructor())
+                methods = removeCovariantsAndInterfaceEquivalents(methods, false);
+            if (argumentTypes == null)
+                return asList(methods); // GROOVY-11683: no covariants or equivalents
         }
 
         Set<MethodNode> bestMethods = new HashSet<>(); // choose best method(s) for each possible receiver
         for (ClassNode rcvr : duckType ? ((UnionTypeClassNode) receiver).getDelegates() : new ClassNode[]{receiver}) {
             var view = methods;
             if (duckType) {
                 view = methods.stream().filter(m -> implementsInterfaceOrSubclassOf(rcvr, m.getDeclaringClass())).toList();
-                if (view.size() > 1 && !first(view).isConstructor())
+                if (view.size() > 1) { // GROOVY-11888
                     view = removeCovariantsAndInterfaceEquivalents(view, true);
+                }
             }
             view = chooseBestMethods(rcvr, view, argumentTypes);
             if (view.isEmpty()) {