1 files changed, 100 insertions, 0 deletions
diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/constraints/PsiMethodReferenceCompatibilityConstraint.java b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/constraints/PsiMethodReferenceCompatibilityConstraint.java
new file mode 100644
index 000000000000..d1de66e453a8
--- /dev/null
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/constraints/PsiMethodReferenceCompatibilityConstraint.java
@@ -0,0 +1,100 @@
+/*
+ * Copyright 2000-2013 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.source.resolve.graphInference.constraints;
+
+import com.intellij.openapi.diagnostic.Logger;
+import com.intellij.psi.*;
+import com.intellij.psi.impl.source.resolve.graphInference.InferenceSession;
+import com.intellij.psi.impl.source.resolve.graphInference.PsiPolyExpressionUtil;
+import com.intellij.psi.util.PsiUtil;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+
+/**
+ * User: anna
+ */
+public class PsiMethodReferenceCompatibilityConstraint implements ConstraintFormula {
+  private static final Logger LOG = Logger.getInstance("#" + PsiMethodReferenceCompatibilityConstraint.class.getName());
+  private final PsiMethodReferenceExpression myExpression;
+  private final PsiType myT;
+
+  public PsiMethodReferenceCompatibilityConstraint(PsiMethodReferenceExpression expression, PsiType t) {
+    myExpression = expression;
+    myT = t;
+  }
+
+  @Override
+  public boolean reduce(InferenceSession session, List<ConstraintFormula> constraints) {
+    if (LambdaHighlightingUtil.checkInterfaceFunctional(myT) != null) {
+      return false;
+    }
+
+    final PsiMethod interfaceMethod = LambdaUtil.getFunctionalInterfaceMethod(myT);
+    if (interfaceMethod == null) {
+      return false;
+    }
+    
+    final PsiSubstitutor substitutor = LambdaUtil.getSubstitutor(interfaceMethod, PsiUtil.resolveGenericsClassInType(myT));
+    final PsiParameter[] parameters = interfaceMethod.getParameterList().getParameters();
+    for (PsiParameter parameter : parameters) {
+      if (!session.isProperType(substitutor.substitute(parameter.getType()))) {
+        return false;
+      }
+    }
+
+    final PsiElement resolve = myExpression.resolve();
+    if (resolve == null) {
+      return false;
+    }
+
+    final PsiType returnType = interfaceMethod.getReturnType();
+    LOG.assertTrue(returnType != null, interfaceMethod);
+    if (PsiType.VOID.equals(returnType)) {
+      return true;
+    }
+
+    if (resolve instanceof PsiMethod) {
+      final PsiMethod method = (PsiMethod)resolve;
+      final PsiType referencedMethodReturnType;
+      if (method.isConstructor()) {
+        final PsiClass containingClass = method.getContainingClass();
+        LOG.assertTrue(containingClass != null, method);
+        referencedMethodReturnType = JavaPsiFacade.getElementFactory(method.getProject()).createType(containingClass);
+      }
+      else {
+        referencedMethodReturnType = method.getReturnType();
+      }
+      LOG.assertTrue(referencedMethodReturnType != null, method);
+
+      if (myExpression.getTypeParameters().length == 0 &&
+          ((PsiMethod)resolve).getTypeParameters().length > 0 && 
+          PsiPolyExpressionUtil.mentionsTypeParameters(returnType, new HashSet<PsiTypeParameter>(Arrays.asList(interfaceMethod.getTypeParameters())))) {
+        //todo target type constraint
+        return true;
+      }
+
+      if (PsiType.VOID.equals(referencedMethodReturnType)) {
+        return false;
+      }
+ 
+      constraints.add(new TypeCompatibilityConstraint(substitutor.substitute(returnType), referencedMethodReturnType));
+    }
+    
+    return true;
+  }
+}