new inference: reject explicitly typed lambda as pertinent to applicability if its return statements are poly

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

@@ -145,6 +145,12 @@ public class InferenceSession {
             if (psiClass instanceof PsiTypeParameter && ((PsiTypeParameter)psiClass).getOwner() == method) return false;
           }
         }
+
+        for (PsiExpression expression : LambdaUtil.getReturnExpressions((PsiLambdaExpression)expr)) {
+          if (PsiPolyExpressionUtil.isPolyExpression(expression)) {
+            return false;
+          }
+        }
       }
       return true;
     }

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

@@ -50,7 +50,7 @@ public class SubtypingConstraint implements ConstraintFormula {
         return true;
       }
       if (PsiType.NULL.equals(myS)) return true;
-      inferenceVariable = session.getInferenceVariable(myT);
+      inferenceVariable = session.getInferenceVariable(myT, false);
       if (inferenceVariable != null) {
         inferenceVariable.addBound(myS, InferenceBound.LOWER);
         return true;