don't duplicate @Delegated methods (IDEA-78066)

plugins/groovy/src/org/jetbrains/plugins/groovy/lang/resolve/ast/DelegatedMethodsContributor.java

@@ -57,6 +57,7 @@ public class DelegatedMethodsContributor extends AstTransformContributor {
       for (PsiMethod method : methods) {
         if (method.isConstructor()) continue;
         if (!deprecated && PsiImplUtil.getAnnotation(method, "java.lang.Deprecated") != null) continue;
+        if (clazz.findCodeMethodsBySignature(method, false).length > 0) continue;
         collector.add(generateDelegateMethod(method, clazz, resolveResult.getSubstitutor()));
       }
     }

plugins/groovy/testdata/groovy/stubGenerator/delegateAnno.test

@@ -9,6 +9,10 @@ class DelegateBarImpl {
     private @Delegate(interfaces=false) Runnable zoo;
     private @Delegate Doo doo;
 }
+class Del2 implements DelegateFoo {
+    @Delegate DelegateFoo foo;
+    def foo() {}
+}
 -----
 public interface DelegateFoo {
 public java.lang.Object foo() ;
@@ -79,4 +83,40 @@ private DelegateFoo foo = null;
 private java.lang.Runnable zoo = null;
 private Doo doo = null;
 }
+---
+public class Del2 extends groovy.lang.GroovyObjectSupport implements DelegateFoo, groovy.lang.GroovyObject {
+public java.lang.Object foo() {
+return null;
+}
+
+public DelegateFoo getFoo() {
+return null;
+}
+
+public void setFoo(DelegateFoo foo) {
+return ;
+}
+
+public java.lang.Object getProperty(java.lang.String property) {
+return null;
+}
+
+public void setProperty(java.lang.String property, java.lang.Object newValue) {
+return ;
+}
+
+public java.lang.Object invokeMethod(java.lang.String name, java.lang.Object args) {
+return null;
+}
+
+public groovy.lang.MetaClass getMetaClass() {
+return null;
+}
+
+public void setMetaClass(groovy.lang.MetaClass metaClass) {
+return ;
+}
+
+private DelegateFoo foo = null;
+}
 ---