hardcode log4j Level expected type (IDEA-201783)

java/java-impl/src/com/intellij/codeInsight/hardcodedDefaultTypes.kt

@@ -33,7 +33,16 @@ private interface DefaultTypeProvider {
 private val providers = createProviders()
 
 private fun createProviders(): MultiMap<MethodArgument, DefaultTypeProvider> {
-  val providers = listOf<Pair<MethodArgument, DefaultTypeProvider>>(
+  val providers = listOf(
+    MethodArgument("log",              0) to object : DefaultTypeProvider {
+      override fun getDefaultType(method: PsiMethod, substitutor: PsiSubstitutor, argument: PsiExpression): PsiType? {
+        if (isDefinedInClass(method, "org.apache.log4j.Category")) {
+          return JavaPsiFacade.getElementFactory(method.project).createTypeFromText("org.apache.log4j.Level", argument)
+        }
+        return null
+      }
+    },
+
     MethodArgument("contains",              0) to takeClassTypeArgument(CommonClassNames.JAVA_UTIL_COLLECTION, 0),
     MethodArgument("remove",                0) to takeClassTypeArgument(CommonClassNames.JAVA_UTIL_COLLECTION, 0),
     MethodArgument("indexOf",               0) to takeClassTypeArgument(CommonClassNames.JAVA_UTIL_LIST, 0),

java/java-tests/testData/codeInsight/completion/smartType/Log4jLevel-out.java

@@ -0,0 +1,8 @@
+import org.apache.log4j.Level;
+
+class Foo {
+  {
+    org.apache.log4j.Category logger;
+    logger.log(Level.FATAL, <caret>)
+  }
+}

java/java-tests/testData/codeInsight/completion/smartType/Log4jLevel.java

@@ -0,0 +1,6 @@
+class Foo {
+  {
+    org.apache.log4j.Category logger;
+    logger.log(F<caret>)
+  }
+}

java/java-tests/testSrc/com/intellij/java/codeInsight/completion/SmartTypeCompletionTest.java

@@ -1315,4 +1315,18 @@ public class SmartTypeCompletionTest extends LightFixtureCompletionTestCase {
     configureByTestName();
     assertOrderedEquals(myFixture.getLookupElementStrings(), "this");
   }
+
+  public void testLog4jLevel() {
+    myFixture.addClass("package org.apache.log4j; " +
+                       "public class Category { " +
+                       "  public void log(Priority priority, Object message); " +
+                       "}" +
+                       "public class Priority { " +
+                       "  final static public Priority FATAL;" + //deprecated
+                       "}" +
+                       "public class Level extends Priority { " +
+                       "  final static public Level FATAL;" +
+                       "}");
+    doTest('\n');
+  }
 }