KT-4913 Smart completion should work after '!'

#KT-4913 Fixed

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

@@ -56,6 +56,7 @@ import org.jetbrains.jet.lang.psi.JetCallElement
 import org.jetbrains.jet.lang.types.TypeUtils
 import org.jetbrains.jet.lang.resolve.calls.context.BasicCallResolutionContext
 import org.jetbrains.jet.lang.resolve.DelegatingBindingTrace
+import org.jetbrains.jet.lang.psi.JetPrefixExpression
 
 enum class Tail {
     COMMA
@@ -74,6 +75,7 @@ class ExpectedInfos(val bindingContext: BindingContext, val moduleDescriptor: Mo
             ?: calculateForElvis(expressionWithType)
             ?: calculateForBlockExpression(expressionWithType)
             ?: calculateForWhenEntryValue(expressionWithType)
+            ?: calculateForExclOperand(expressionWithType)
             ?: getFromBindingContext(expressionWithType)
     }
 
@@ -242,6 +244,12 @@ class ExpectedInfos(val bindingContext: BindingContext, val moduleDescriptor: Mo
         }
     }
 
+    private fun calculateForExclOperand(expressionWithType: JetExpression): Collection<ExpectedInfo>? {
+        val prefixExpression = expressionWithType.getParent() as? JetPrefixExpression ?: return null
+        if (prefixExpression.getOperationToken() != JetTokens.EXCL) return null
+        return listOf(ExpectedInfo(KotlinBuiltIns.getInstance().getBooleanType(), null))
+    }
+
     private fun getFromBindingContext(expressionWithType: JetExpression): Collection<ExpectedInfo>? {
         val expectedType = bindingContext[BindingContext.EXPECTED_EXPRESSION_TYPE, expressionWithType] ?: return null
         return listOf(ExpectedInfo(expectedType, null))

idea/testData/completion/smart/AfterExclSign.kt

@@ -0,0 +1,6 @@
+fun foo(p1: Boolean, p2: String) {
+    if (!<caret>)
+}
+
+// EXIST: p1
+// ABSENT: p2

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

@@ -32,6 +32,11 @@ import org.jetbrains.jet.completion.AbstractJvmSmartCompletionTest;
 @SuppressWarnings("all")
 @TestMetadata("idea/testData/completion/smart")
 public class JvmSmartCompletionTestGenerated extends AbstractJvmSmartCompletionTest {
+    @TestMetadata("AfterExclSign.kt")
+    public void testAfterExclSign() throws Exception {
+        doTest("idea/testData/completion/smart/AfterExclSign.kt");
+    }
+    
     public void testAllFilesPresentInSmart() throws Exception {
         JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), "org.jetbrains.jet.generators.tests.TestsPackage", new File("idea/testData/completion/smart"), Pattern.compile("^(.+)\\.kt$"), true);
     }