don't fold lambda if there's an unresolved type in the throws list

java/java-impl/src/com/intellij/codeInsight/folding/impl/JavaFoldingBuilder.java

@@ -564,7 +564,7 @@ public class JavaFoldingBuilder extends CustomFoldingBuilder implements DumbAwar
     }
   }
 
-  private static boolean hasOnlyOneMethod(@NotNull PsiAnonymousClass anonymousClass) {
+  private static boolean hasOnlyOneMethod(@NotNull PsiAnonymousClass anonymousClass, boolean checkResolve) {
     if (anonymousClass.getFields().length != 0) {
       return false;
     }
@@ -575,7 +575,20 @@ public class JavaFoldingBuilder extends CustomFoldingBuilder implements DumbAwar
       return false;
     }
 
-    return anonymousClass.getMethods().length == 1;
+    if (anonymousClass.getMethods().length != 1) {
+      return false;
+    }
+
+    if (checkResolve) {
+      PsiReferenceList throwsList = anonymousClass.getMethods()[0].getThrowsList();
+      for (PsiClassType type : throwsList.getReferencedTypes()) {
+        if (type.resolve() == null) {
+          return false;
+        }
+      }
+    }
+
+    return true;
   }
 
   private boolean addClosureFolding(final PsiClass aClass, final Document document, final List<FoldingDescriptor> foldElements,
@@ -593,7 +606,7 @@ public class JavaFoldingBuilder extends CustomFoldingBuilder implements DumbAwar
         final PsiExpressionList argumentList = expression.getArgumentList();
         if (argumentList != null && argumentList.getExpressions().length == 0) {
           final PsiMethod[] methods = anonymousClass.getMethods();
-          if (hasOnlyOneMethod(anonymousClass) && (quick || seemsLikeLambda(anonymousClass.getBaseClassType().resolve()))) {
+          if (hasOnlyOneMethod(anonymousClass, !quick) && (quick || seemsLikeLambda(anonymousClass.getBaseClassType().resolve()))) {
             final PsiMethod method = methods[0];
             final PsiCodeBlock body = method.getBody();
             if (body != null) {

java/java-tests/testSrc/com/intellij/codeInsight/folding/JavaFoldingTest.groovy

@@ -195,6 +195,23 @@ class Test {
     assert closureStartFold
   }
 
+  public void "test no closure folding when the method throws an unresolved exception"() {
+    def text = """\
+class Test {
+    void test() { new Runnable() {
+      public void run() throws Asadfsdafdfasd {
+        System.out.println(<caret>);
+      }
+    };
+  }
+}
+"""
+
+    configure text
+    def foldingModel = myFixture.editor.foldingModel as FoldingModelImpl
+    assert !foldingModel.getCollapsedRegionAtOffset(text.indexOf("Runnable"))
+  }
+
   public void testFindInFolding() {
     def text = """\
 class Test {