Fixed KT-6408 Completion auto-popup prevents smooth typing of "!in"

#KT-6408 Fixed

idea/src/org/jetbrains/jet/plugin/completion/KeywordCompletion.kt

@@ -33,6 +33,7 @@ import org.jetbrains.jet.lang.psi.psiUtil.siblings
 import org.jetbrains.jet.lexer.JetTokens.*
 import org.jetbrains.jet.lang.psi.psiUtil.prevLeafSkipWhitespacesAndComments
 import org.jetbrains.jet.lang.psi.psiUtil.getNonStrictParentOfType
+import com.intellij.psi.tree.IElementType
 
 class KeywordLookupObject(val keyword: String)
 
@@ -158,9 +159,9 @@ object KeywordCompletion {
             val postfix = KEYWORD_TO_DUMMY_POSTFIX[keywordTokenType] ?: ""
             val file = psiFactory.createFile(prefixText + keywordTokenType.getValue() + postfix)
             val elementAt = file.findElementAt(prefixText.length)!!
-            val nodeType = elementAt.getNode()!!.getElementType()
+
             when {
-                nodeType != keywordTokenType -> false
+                !elementAt.getNode()!!.getElementType().matchesKeyword(keywordTokenType) -> false
 
                 elementAt.getNonStrictParentOfType<PsiErrorElement>() != null -> false
 
@@ -171,6 +172,15 @@ object KeywordCompletion {
         }
     }
 
+    private fun IElementType.matchesKeyword(keywordType: JetKeywordToken): Boolean {
+        return when(this) {
+            keywordType -> true
+            NOT_IN -> keywordType == IN_KEYWORD
+            NOT_IS -> keywordType == IS_KEYWORD
+            else -> false
+        }
+    }
+
     // builds text within scope (or from the start of the file) before position element excluding almost all declarations
     private fun buildReducedContextBefore(builder: StringBuilder, position: PsiElement, scope: PsiElement?) {
         if (position == scope) return

idea/testData/completion/keywords/NotInNotIs.kt

@@ -0,0 +1,6 @@
+fun foo(v: String) {
+    if (v !<caret>)
+}
+
+// EXIST: in
+// EXIST: is

idea/tests/org/jetbrains/jet/completion/KeywordCompletionTestGenerated.java

@@ -19,7 +19,6 @@ package org.jetbrains.jet.completion;
 import com.intellij.testFramework.TestDataPath;
 import org.jetbrains.jet.JUnit3RunnerWithInners;
 import org.jetbrains.jet.JetTestUtils;
-import org.jetbrains.jet.test.InnerTestClasses;
 import org.jetbrains.jet.test.TestMetadata;
 import org.junit.runner.RunWith;
 
@@ -246,6 +245,12 @@ public class KeywordCompletionTestGenerated extends AbstractKeywordCompletionTes
         doTest(fileName);
     }
 
+    @TestMetadata("NotInNotIs.kt")
+    public void testNotInNotIs() throws Exception {
+        String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/keywords/NotInNotIs.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("PrefixMatcher.kt")
     public void testPrefixMatcher() throws Exception {
         String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/keywords/PrefixMatcher.kt");