varargs: prefer Object... (IDEA-55412)

java/java-impl/src/com/intellij/psi/scope/conflictResolvers/JavaMethodsConflictResolver.java

@@ -16,11 +16,13 @@
 package com.intellij.psi.scope.conflictResolvers;
 
 import com.intellij.openapi.diagnostic.Logger;
+import com.intellij.openapi.util.Comparing;
 import com.intellij.pom.java.LanguageLevel;
 import com.intellij.psi.*;
 import com.intellij.psi.infos.CandidateInfo;
 import com.intellij.psi.infos.MethodCandidateInfo;
 import com.intellij.psi.scope.PsiConflictResolver;
+import com.intellij.psi.search.GlobalSearchScope;
 import com.intellij.psi.util.*;
 import gnu.trove.THashSet;
 import gnu.trove.TIntArrayList;
@@ -57,6 +59,9 @@ public class JavaMethodsConflictResolver implements PsiConflictResolver{
     if (conflicts.isEmpty()) return null;
     if (conflicts.size() == 1) return conflicts.get(0);
 
+    checkVarargMethods(conflicts, myActualParameterTypes.length);
+    if (conflicts.size() == 1) return conflicts.get(0);
+
     boolean atLeastOneMatch = checkParametersNumber(conflicts, myActualParameterTypes.length, true);
     if (conflicts.size() == 1) return conflicts.get(0);
 
@@ -457,4 +462,31 @@ public class JavaMethodsConflictResolver implements PsiConflictResolver{
     }
     return substitutor;
   }
+
+  public void checkVarargMethods(final List<CandidateInfo> conflicts,
+                                 final int argumentsCount) {
+    PsiMethod objectVararg = null;
+    for (CandidateInfo conflict : conflicts) {
+      final PsiMethod method = (PsiMethod)conflict.getElement();
+      final int parametersCount = method.getParameterList().getParametersCount();
+      if (method.isVarArgs() && parametersCount - 1 == argumentsCount) {
+        final PsiType type = method.getParameterList().getParameters()[parametersCount - 1].getType();
+        final PsiType componentType = ((PsiArrayType)type).getComponentType();
+        final PsiClassType classType = PsiType.getJavaLangObject(method.getManager(), GlobalSearchScope.allScope(method.getProject()));
+        if (Comparing.equal(componentType, classType)) {
+          objectVararg = method;
+        }
+      }
+    }
+
+    if (objectVararg != null) {
+      for (Iterator<CandidateInfo> iterator = conflicts.iterator(); iterator.hasNext(); ) {
+        CandidateInfo conflict = iterator.next();
+        PsiMethod method = (PsiMethod)conflict.getElement();
+        if (method != objectVararg && method.isVarArgs() && method.getParameterList().getParametersCount() - 1 == argumentsCount) {
+          iterator.remove();
+        }
+      }
+    }
+  }
 }

java/java-tests/testData/psi/resolve/method/generics/FilterVarargsVsVarargs3.java

@@ -0,0 +1,9 @@
+class XY {
+    private void f(Object... bs) {}
+
+    private void f(int... is) {}
+
+    public static void main(String[] args) {
+            <ref>f();
+    }
+}

java/java-tests/testData/psi/resolve/method/generics/FilterVarargsVsVarargs4.java

@@ -0,0 +1,9 @@
+class XY {
+    private void f(String... bs) {}
+
+    private void f(int... is) {}
+
+    public static void main(String[] args) {
+            <ref>f();
+    }
+}

java/java-tests/testSrc/com/intellij/psi/resolve/ResolveMethod15Test.java

@@ -249,6 +249,32 @@ public class ResolveMethod15Test extends Resolve15TestCase {
     assertEquals(2, candidates.length);
   }
 
+  public void testFilterVarargsVsVarargs3() throws Exception {
+    final PsiReference ref = configureByFile();
+    assertThat(ref, instanceOf(PsiReferenceExpression.class));
+    final PsiReferenceExpression refExpr = (PsiReferenceExpression)ref;
+    PsiCallExpression call = (PsiCallExpression) refExpr.getParent();
+    JavaResolveResult resolveResult = call.resolveMethodGenerics();
+    assertNotNull(resolveResult.getElement());
+    assertFalse(resolveResult.isValidResult());
+
+    final JavaResolveResult[] candidates = refExpr.multiResolve(false);
+    assertEquals(1, candidates.length);
+  }
+
+  public void testFilterVarargsVsVarargs4() throws Exception {
+    final PsiReference ref = configureByFile();
+    assertThat(ref, instanceOf(PsiReferenceExpression.class));
+    final PsiReferenceExpression refExpr = (PsiReferenceExpression)ref;
+    PsiCallExpression call = (PsiCallExpression) refExpr.getParent();
+    JavaResolveResult resolveResult = call.resolveMethodGenerics();
+    assertNull(resolveResult.getElement());
+    assertFalse(resolveResult.isValidResult());
+
+    final JavaResolveResult[] candidates = refExpr.multiResolve(false);
+    assertEquals(2, candidates.length);
+  }
+
   //IDEADEV-3313
   public void testCovariantReturnTypes() throws Exception {
     final PsiReference ref = configureByFile();