pertinent to applicability: process return statements inside block lambda

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

@@ -260,7 +260,8 @@ public class InferenceSession {
             if (isTypeParameterType(owner, paramType)) return false;
           }
         }
-        else if (expectedReturnType != null && parent instanceof PsiLambdaExpression) {
+        else if (expectedReturnType != null && (parent instanceof PsiLambdaExpression ||
+                                                parent instanceof PsiReturnStatement && PsiTreeUtil.getParentOfType(parent, PsiLambdaExpression.class, true, PsiMethod.class) != null)) {
           if (isTypeParameterType(method, expectedReturnType)) return false;
           paramType = expectedReturnType;
         }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/graphInference/PertinentToApplicabilityCheckForBlockLambda.java

@@ -0,0 +1,17 @@
+
+import java.util.concurrent.Callable;
+
+class Test {
+
+  public static void main(String[] args) throws Exception {
+    Runnable iteration = compute(() -> {
+      if (true) return () -> {};
+      return null;
+    });
+    Runnable iteration2 = compute(() -> () -> {});
+  }
+
+  static <T> T compute(Callable<T> c) throws Exception {
+    return c.call();
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/highlighting/NoInferenceResult.java

@@ -16,7 +16,7 @@ class NoInferenceResult {
 
     void test() {
         m((String s1) ->  <error descr="Target type of a lambda conversion must be an interface">(String s2) ->  s1 + s2</error>);
-        m(<error descr="B is not a functional interface">(String s1) ->  {return (String s2) ->  s1 + s2;}</error>);
+        m((String s1) ->  {return <error descr="Target type of a lambda conversion must be an interface">(String s2) ->  s1 + s2</error>;});
 
         m((String s1) -> s1.length());
         m((String s1) -> s1);

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

@@ -175,6 +175,8 @@ public class GraphInferenceHighlightingTest extends LightDaemonAnalyzerTestCase
   public void testRecursiveTypeWithCapture() { doTest(); }
   public void testFreshVariablesDuringApplicabilityCheck() { doTest(); }
 
+  public void testPertinentToApplicabilityCheckForBlockLambda() { doTest(); }
+
   public void testApplicabilityCheckFailsExpressionTypeCheckPasses() throws Exception {
     doTest();
   }