IDEA-78555 Intellij fails to compile Groovy class with @Delegate when there is also Java class

java/java-psi-impl/src/com/intellij/psi/impl/PsiImplUtil.java

@@ -525,4 +525,9 @@ public class PsiImplUtil {
     }
     return result;
   }
+
+  public static boolean isVarArgs(PsiMethod method) {
+    PsiParameter[] parameters = method.getParameterList().getParameters();
+    return parameters.length > 0 && parameters[parameters.length - 1].isVarArgs();
+  }
 }

java/java-psi-impl/src/com/intellij/psi/impl/light/LightTypeParameterListBuilder.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2000-2011 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.psi.impl.light;
+
+import com.intellij.lang.Language;
+import com.intellij.psi.*;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author Max Medvedev
+ */
+public class LightTypeParameterListBuilder extends LightElement implements PsiTypeParameterList {
+  private final List<PsiTypeParameter> myParameters = new ArrayList<PsiTypeParameter>();
+  private PsiTypeParameter[] cached = null;
+
+  protected LightTypeParameterListBuilder(PsiManager manager, final Language language) {
+    super(manager, language);
+  }
+
+  @Override
+  public String toString() {
+    return "Light type parameter list";
+  }
+
+  @Override
+  public void accept(@NotNull PsiElementVisitor visitor) {
+    if (visitor instanceof JavaElementVisitor) {
+      ((JavaElementVisitor)visitor).visitTypeParameterList(this);
+    }
+    else {
+      visitor.visitElement(this);
+    }
+  }
+
+  @Override
+  public PsiTypeParameter[] getTypeParameters() {
+    if (cached == null) {
+      if (myParameters.size() == 0) {
+        cached = PsiTypeParameter.EMPTY_ARRAY;
+      }
+      else {
+        cached = myParameters.toArray(new PsiTypeParameter[myParameters.size()]);
+      }
+    }
+    return cached;
+  }
+
+  @Override
+  public int getTypeParameterIndex(PsiTypeParameter typeParameter) {
+    return myParameters.indexOf(typeParameter);
+  }
+
+  public void addParameter(PsiTypeParameter parameter) {
+    cached = null;
+    myParameters.add(parameter);
+  }
+}

java/java-psi-impl/src/com/intellij/psi/impl/source/PsiMethodImpl.java

@@ -316,8 +316,7 @@ public class PsiMethodImpl extends JavaStubPsiElement<PsiMethodStub> implements
       return stub.isVarArgs();
     }
 
-    PsiParameter[] parameters = getParameterList().getParameters();
-    return parameters.length > 0 && parameters[parameters.length - 1].isVarArgs();
+    return PsiImplUtil.isVarArgs(this);
   }
 
   @Override