overload resolution: don't include constraints on functional expressions into applicability check during overload resolution (IDEA-150745)

java/java-psi-api/src/com/intellij/psi/infos/MethodCandidateInfo.java

@@ -136,6 +136,8 @@ public class MethodCandidateInfo extends CandidateInfo{
     @ApplicabilityLevelConstant int level = computeForOverloadedCandidate(new Computable<Integer>() {
       @Override
       public Integer compute() {
+        //arg types are calculated here without additional constraints:
+        //non-pertinent to applicability arguments of arguments would be skipped 
         PsiType[] argumentTypes = getArgumentTypes();
         if (argumentTypes == null) {
           return ApplicabilityLevel.NOT_APPLICABLE;

java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java

@@ -358,7 +358,7 @@ public class InferenceSession {
         return;
       }
 
-      if (parameters != null && args != null) {
+      if (parameters != null && args != null && !MethodCandidateInfo.isOverloadCheck()) {
         final Set<ConstraintFormula> additionalConstraints = new LinkedHashSet<ConstraintFormula>();
         if (parameters.length > 0) {
           collectAdditionalConstraints(parameters, args, properties.getMethod(), mySiteSubstitutor, additionalConstraints, properties.isVarargs(), initialSubstitutor);

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/overloadResolution/DonotIncludeAdditionalConstraintsDuringApplicabilityChecksInsideOverloadResolution.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2016. Lorem ipsum dolor sit amet, consectetur adipiscing elit.
+ * Morbi non lorem porttitor neque feugiat blandit. Ut vitae ipsum eget quam lacinia accumsan.
+ * Etiam sed turpis ac ipsum condimentum fringilla. Maecenas magna.
+ * Proin dapibus sapien vel ante. Aliquam erat volutpat. Pellentesque sagittis ligula eget metus.
+ * Vestibulum commodo. Ut rhoncus gravida arcu.
+ */
+
+package usages;
+
+import java.util.function.Function;
+
+class Test {
+  {
+    valueOf(processFirst(<error descr="no instance(s) of type variable(s)  exist so that Integer conforms to char[]">x -> x</error>));
+  }
+
+  public static <V> V processFirst(Function<Integer,V> f){
+    return f.apply(1);
+  }
+  static void valueOf(Object o) {
+    System.out.println(o);
+  }
+  static void valueOf(char[] c) {
+    System.out.println(c);
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/overloadResolution/MethodReferenceWithTypeArgs.java

@@ -6,13 +6,13 @@ import java.util.stream.Stream;
 class Test {
 
   void foo() {
-    log(get(TreeSet<String>::new));
+    log(get(<error descr="Bad return type in method reference: cannot convert java.util.TreeSet<java.lang.String> to C">TreeSet<String>::new</error>));
   }
 
-  private void <warning descr="Private method 'log(java.lang.String[])' is never used">log</warning>(String params[]) {
+  private void log(String params[]) {
     System.out.println(params);
   }
-  private void log(Object params) {
+  private void <warning descr="Private method 'log(java.lang.Object)' is never used">log</warning>(Object params) {
     System.out.println(params);
   }
 

java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/OverloadResolutionTest.java

@@ -196,6 +196,10 @@ public class OverloadResolutionTest extends LightDaemonAnalyzerTestCase {
     doTest(true);
   }
 
+  public void testDonotIncludeAdditionalConstraintsDuringApplicabilityChecksInsideOverloadResolution() throws Exception {
+    doTest(true);
+  }
+
   private void doTest() {
     doTest(true);
   }