Implemented "Go to type declaration" for Kotlin entities.

#KT-1318 fixed

idea/src/META-INF/plugin.xml

@@ -92,6 +92,7 @@
       <codeInsight.parameterInfo language="jet" implementationClass="org.jetbrains.jet.plugin.parameterInfo.JetFunctionParameterInfoHandler"/>
 
       <codeInsight.gotoSuper language="jet" implementationClass="org.jetbrains.jet.plugin.codeInsight.GotoSuperActionHandler" />
+      <typeDeclarationProvider implementation="org.jetbrains.jet.plugin.codeInsight.JetTypeDeclarationProvider" />
 
       <completion.contributor language="jet" id="JetKeywordCompletionContributor" order="first"
                               implementationClass="org.jetbrains.jet.plugin.completion.JetKeywordCompletionContributor"/>

idea/src/org/jetbrains/jet/plugin/codeInsight/JetTypeDeclarationProvider.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2010-2012 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.jet.plugin.codeInsight;
+
+import com.intellij.codeInsight.navigation.actions.TypeDeclarationProvider;
+import com.intellij.psi.PsiElement;
+import org.jetbrains.jet.lang.descriptors.CallableDescriptor;
+import org.jetbrains.jet.lang.descriptors.ClassifierDescriptor;
+import org.jetbrains.jet.lang.descriptors.DeclarationDescriptor;
+import org.jetbrains.jet.lang.psi.JetElement;
+import org.jetbrains.jet.lang.psi.JetFile;
+import org.jetbrains.jet.lang.resolve.BindingContext;
+import org.jetbrains.jet.lang.resolve.BindingContextUtils;
+import org.jetbrains.jet.lang.types.JetType;
+import org.jetbrains.jet.plugin.project.WholeProjectAnalyzerFacade;
+
+/**
+ * @author Evgeny Gerashchenko
+ * @since 07.05.12
+ */
+public class JetTypeDeclarationProvider implements TypeDeclarationProvider {
+    @Override
+    public PsiElement[] getSymbolTypeDeclarations(PsiElement symbol) {
+        if (symbol instanceof JetElement && symbol.getContainingFile() instanceof JetFile) {
+            BindingContext bindingContext =
+                    WholeProjectAnalyzerFacade.analyzeProjectWithCacheOnAFile((JetFile) symbol.getContainingFile()).getBindingContext();
+            DeclarationDescriptor descriptor = bindingContext.get(BindingContext.DECLARATION_TO_DESCRIPTOR, symbol);
+            if (descriptor instanceof CallableDescriptor) {
+                JetType type = ((CallableDescriptor) descriptor).getReturnType();
+                if (type != null) {
+                    ClassifierDescriptor classifierDescriptor = type.getConstructor().getDeclarationDescriptor();
+                    if (classifierDescriptor != null) {
+                        PsiElement typeElement = BindingContextUtils.descriptorToDeclaration(bindingContext, classifierDescriptor);
+                        if (typeElement != null) {
+                            return new PsiElement[] {typeElement};
+                        }
+                    }
+                }
+            }
+        }
+        return new PsiElement[0];
+    }
+}