Implement var type information display as tooltip

ide/editor.completion/src/org/netbeans/modules/editor/completion/Bundle.properties

@@ -52,5 +52,5 @@ COMPL_CANCEL_ICON_BASE=org/netbeans/modules/editor/completion/resources/open_in_
 
 completion-show-main_menu_item=Complete &Code...
 documentation-show-main_menu_item=Show &Documentation
-tooltip-show-main_menu_item=&Show Method Parameters
+tooltip-show-main_menu_item=&Show Method Parameters and Typeinfos
 

ide/editor.lib/src/org/netbeans/editor/Bundle.properties

@@ -151,7 +151,7 @@ documentation-show=Show Documentation Popup
 show-popup-menu=Show Popup Menu
 # Alternate name key for show-popup-menu action
 org.openide.actions.PopupAction=Show Popup Menu
-tooltip-show=Show Method Parameters
+tooltip-show=Show Method Parameters and Typeinfos
 run-macro=Run Macro
 split-line=Split Line
 start-macro-recording=Start Macro Recording

java/java.completion/src/org/netbeans/modules/java/completion/JavaTooltipTask.java

@@ -19,31 +19,32 @@
 
 package org.netbeans.modules.java.completion;
 
+import com.sun.source.tree.*;
+import com.sun.source.util.SourcePositions;
+import com.sun.source.util.TreePath;
+import com.sun.source.util.Trees;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.concurrent.Callable;
-
 import javax.lang.model.element.Element;
-import static javax.lang.model.element.ElementKind.*;
 import javax.lang.model.element.ExecutableElement;
-import static javax.lang.model.element.Modifier.*;
 import javax.lang.model.element.TypeElement;
 import javax.lang.model.element.VariableElement;
 import javax.lang.model.type.*;
 import javax.lang.model.util.Types;
-
-import com.sun.source.tree.*;
-import com.sun.source.util.SourcePositions;
-import com.sun.source.util.TreePath;
-import com.sun.source.util.Trees;
-
 import org.netbeans.api.annotations.common.NullAllowed;
+import org.netbeans.api.java.lexer.JavaTokenId;
 import org.netbeans.api.java.source.*;
+import org.netbeans.api.lexer.TokenSequence;
 import org.openide.util.NbBundle;
 
+import static java.util.Arrays.asList;
+import static javax.lang.model.element.ElementKind.*;
+import static javax.lang.model.element.Modifier.*;
+
 /**
  *
  * @author Dusan Balek
@@ -85,6 +86,20 @@ public int getTooltipOffset() {
 
     @Override
     protected void resolve(CompilationController controller) throws IOException {
+        Integer varOffset = findVarAtCaret(controller);
+        if(varOffset != null && varOffset <= caretOffset && (varOffset + 3) >= caretOffset) {
+            controller.toPhase(JavaSource.Phase.RESOLVED);
+            Trees trees = controller.getTrees();
+            TreeUtilities treeUtilities = controller.getTreeUtilities();
+            TreePath caretPath = treeUtilities.pathFor(varOffset + 1);
+            TypeMirror typeMirror = trees.getTypeMirror(caretPath);
+            if (typeMirror.getKind() != TypeKind.ERROR) {
+                toolTipOffset = controller.getSnapshot().getOriginalOffset(varOffset);
+                anchorOffset = toolTipOffset;
+                toolTipData = asList(asList(controller.getTypeUtilities().getTypeName(typeMirror).toString()));
+            }
+        }
+
         Env env = getCompletionEnvironment(controller, true);
         if (env == null) {
             return;
@@ -226,6 +241,21 @@ public boolean accept(Element e, TypeMirror t) {
         }
     }
 
+    private Integer findVarAtCaret(CompilationController controller) {
+        TokenSequence<JavaTokenId> ts = controller.getTokenHierarchy().tokenSequence(JavaTokenId.language());
+        int offset2 = controller.getSnapshot().getEmbeddedOffset(caretOffset);
+        if (offset2 >= 0 && offset2 <= controller.getText().length()) {
+            ts.move(offset2);
+            if(ts.moveNext() && ts.token().id() == JavaTokenId.VAR) {
+                return ts.offset();
+            }
+            if(ts.movePrevious() && ts.token().id() == JavaTokenId.VAR) {
+                return ts.offset();
+            }
+        }
+        return null;
+    }
+
     private List<List<String>> getMatchingParams(CompilationInfo info, TypeMirror type, Iterable<? extends Element> elements, String name, TypeMirror[] argTypes, Types types) {
         List<List<String>> ret = new ArrayList<>();
         TypeUtilities tu = info.getTypeUtilities();

java/java.completion/test/unit/data/goldenfiles/org/netbeans/modules/java/completion/JavaTooltipTaskTest/17/VarSampleBounds1.pass

@@ -0,0 +1,5 @@
+Query offset: 901
+Anchor offset: 0
+Tooltip offset: 0
+Tooltip index: 0
+

java/java.completion/test/unit/data/goldenfiles/org/netbeans/modules/java/completion/JavaTooltipTaskTest/17/VarSampleBounds2.pass

@@ -0,0 +1,10 @@
+Query offset: 902
+Anchor offset: 902
+Tooltip offset: 902
+Tooltip index: 0
+
+[
+	[
+		Iterator<String>
+	[
+]

java/java.completion/test/unit/data/goldenfiles/org/netbeans/modules/java/completion/JavaTooltipTaskTest/17/VarSampleBounds3.pass

@@ -0,0 +1,10 @@
+Query offset: 903
+Anchor offset: 902
+Tooltip offset: 902
+Tooltip index: 0
+
+[
+	[
+		Iterator<String>
+	[
+]

java/java.completion/test/unit/data/goldenfiles/org/netbeans/modules/java/completion/JavaTooltipTaskTest/17/VarSampleBounds4.pass

@@ -0,0 +1,10 @@
+Query offset: 905
+Anchor offset: 902
+Tooltip offset: 902
+Tooltip index: 0
+
+[
+	[
+		Iterator<String>
+	[
+]

java/java.completion/test/unit/data/goldenfiles/org/netbeans/modules/java/completion/JavaTooltipTaskTest/17/VarSampleBounds5.pass

@@ -0,0 +1,5 @@
+Query offset: 906
+Anchor offset: 0
+Tooltip offset: 0
+Tooltip index: 0
+

java/java.completion/test/unit/data/goldenfiles/org/netbeans/modules/java/completion/JavaTooltipTaskTest/17/VarSampleType1.pass

@@ -0,0 +1,10 @@
+Query offset: 1063
+Anchor offset: 1062
+Tooltip offset: 1062
+Tooltip index: 0
+
+[
+	[
+		String
+	[
+]

java/java.completion/test/unit/data/goldenfiles/org/netbeans/modules/java/completion/JavaTooltipTaskTest/17/VarSampleType2.pass

@@ -0,0 +1,10 @@
+Query offset: 1088
+Anchor offset: 1086
+Tooltip offset: 1086
+Tooltip index: 0
+
+[
+	[
+		X<Double>
+	[
+]

java/java.completion/test/unit/data/goldenfiles/org/netbeans/modules/java/completion/JavaTooltipTaskTest/17/VarSampleType3.pass

@@ -0,0 +1,10 @@
+Query offset: 1172
+Anchor offset: 1172
+Tooltip offset: 1172
+Tooltip index: 0
+
+[
+	[
+		X1 & X2
+	[
+]

java/java.completion/test/unit/data/org/netbeans/modules/java/completion/data/VarSample.java

@@ -0,0 +1,60 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 test;
+
+public class Test {
+
+    private void test(java.util.List<String> l) {
+        var v1 = l.iterator();
+    }
+
+    public static class X<T> {
+
+        public static void main(String[] args) {
+            X<String> x = new X<>();
+            var a = "";
+            var y = x.run1()
+                    .run2()
+                    .run3();
+            var z = x.x("Hallo", 42);
+        }
+
+        public <X, Y, Z extends X1 & X2> Z x(Y y, X x) {
+            return null;
+        }
+
+        public X<Integer> run1() {
+            return null;
+        }
+
+        public X<String> run2() {
+            return null;
+        }
+
+        public X<Double> run3() {
+            return null;
+        }
+
+        interface X1 {
+        }
+
+        interface X2 {
+        }
+    }
+}

java/java.completion/test/unit/src/org/netbeans/modules/java/completion/JavaTooltipTaskTest.java

@@ -0,0 +1,125 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.netbeans.modules.java.completion;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.StringWriter;
+import java.util.Collections;
+import java.util.List;
+import javax.swing.text.Document;
+import org.netbeans.api.java.lexer.JavaTokenId;
+import org.netbeans.api.lexer.Language;
+import org.netbeans.modules.parsing.api.ParserManager;
+import org.netbeans.modules.parsing.api.Source;
+import org.openide.cookies.EditorCookie;
+import org.openide.filesystems.FileObject;
+import org.openide.filesystems.FileUtil;
+import org.openide.loaders.DataObject;
+
+import static junit.framework.TestCase.assertNotNull;
+
+public class JavaTooltipTaskTest extends CompletionTestBaseBase {
+
+    public JavaTooltipTaskTest(String testName) {
+        super(testName, "org/netbeans/modules/java/completion/JavaTooltipTaskTest");
+    }
+
+    public void testVarBounds() throws Exception {
+        assertResult("17", "VarSample", "VarSampleBounds1.pass", 901);
+        assertResult("17", "VarSample", "VarSampleBounds2.pass", 902);
+        assertResult("17", "VarSample", "VarSampleBounds3.pass", 903);
+        assertResult("17", "VarSample", "VarSampleBounds4.pass", 905);
+        assertResult("17", "VarSample", "VarSampleBounds5.pass", 906);
+    }
+
+    public void testVarTypes() throws Exception {
+        assertResult("17", "VarSample", "VarSampleType1.pass", 1063);
+        assertResult("17", "VarSample", "VarSampleType2.pass", 1088);
+        assertResult("17", "VarSample", "VarSampleType3.pass", 1172);
+    }
+
+    private void assertResult(String sourceLevel, String source, String goldenFileName, int pos) throws Exception {
+        this.sourceLevel.set(sourceLevel);
+        File testSource = new File(getWorkDir(), "test/Test.java");
+        testSource.getParentFile().mkdirs();
+        copyToWorkDir(new File(getDataDir(), "org/netbeans/modules/java/completion/data/" + source + ".java"), testSource);
+        FileObject testSourceFO = FileUtil.toFileObject(testSource);
+        assertNotNull(testSourceFO);
+        DataObject testSourceDO = DataObject.find(testSourceFO);
+        assertNotNull(testSourceDO);
+        EditorCookie ec = (EditorCookie) testSourceDO.getCookie(EditorCookie.class);
+        assertNotNull(ec);
+        final Document doc = ec.openDocument();
+        assertNotNull(doc);
+        doc.putProperty(Language.class, JavaTokenId.language());
+        doc.putProperty("mimeType", "text/x-java");
+        Source s = Source.create(doc);
+        JavaTooltipTask task = JavaTooltipTask.create(pos, () -> false);
+        ParserManager.parse(Collections.singletonList(s), task);
+
+        String reference = getGoldFileContents(goldenFileName);
+        StringWriter result = new StringWriter();
+        result.write("Query offset: ");
+        result.write(String.valueOf(pos));
+        result.write("\n");
+        result.write("Anchor offset: ");
+        result.write(String.valueOf(task.getAnchorOffset()));
+        result.write("\n");
+        result.write("Tooltip offset: ");
+        result.write(String.valueOf(task.getTooltipOffset()));
+        result.write("\n");
+        result.write("Tooltip index: ");
+        result.write(String.valueOf(task.getTooltipIndex()));
+        result.write("\n\n");
+
+        if (task.getTooltipData() != null) {
+            result.write("[\n");
+            for (List<String> element : task.getTooltipData()) {
+                result.write("\t[\n");
+                for (String type : element) {
+                    result.write("\t\t");
+                    result.write(type);
+                    result.write("\n");
+                }
+                result.write("\t[\n");
+            }
+            result.write("]\n");
+        }
+
+        assertEquals(reference, result.toString());
+    }
+
+    @SuppressWarnings("NestedAssignment")
+    private String getGoldFileContents(String goldenFileName) throws IOException {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        File goldenFile = getGoldenFile(goldenFileName);
+        try(InputStream is = new FileInputStream(goldenFile)) {
+            int read;
+            byte[] buffer = new byte[1024];
+            while((read = is.read(buffer)) > 0) {
+                baos.write(buffer, 0, read);
+            }
+        }
+        return baos.toString("UTF-8");
+    }
+}