[groovy] IDEA-208346 Highlight illegal single argument lambda

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/GroovyBundle.properties

@@ -102,6 +102,7 @@ change.modifier.not=Make ''{0}'' not {1}
 change.modifier.family.name=Change modifiers
 parameter.cast.fix=Cast {0,number,ordinal} parameter to {1}
 action.convert.lambda.to.closure=Convert lambda to closure
+add.parenthesis.to.lambda.parameter.list=Add parenthesis to parameter list
 # suppress inspection "UnusedProperty"
 packageLocal.visibility.presentation=default visible
 # suppress inspection "UnusedProperty"
@@ -193,6 +194,7 @@ unsupported.negated.instanceof=Negated 'instanceof' is not supported in current
 unsupported.elvis.assignment=Elvis assignment is not supported in current version
 unsupported.safe.index.access=Safe index access is not supported in current version
 unsupported.lambda=Lambdas are not supported in current version
+illegal.single.argument.lambda=Single argument form of lambda is available only as right part of assignment expression or as argument inside method call
 
 #Override and implement
 method.is.not.implemented=Method ''{0}'' is not implemented

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/annotator/GroovyAnnotator30.kt

@@ -1,4 +1,4 @@
-// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 
 package org.jetbrains.plugins.groovy.annotator
 
@@ -7,9 +7,16 @@ import com.intellij.psi.PsiClass
 import com.intellij.psi.PsiModifier
 import com.intellij.psi.util.PsiTreeUtil
 import org.jetbrains.plugins.groovy.GroovyBundle
+import org.jetbrains.plugins.groovy.annotator.intentions.AddParenthesisToLambdaParameterAction
 import org.jetbrains.plugins.groovy.codeInspection.bugs.GrRemoveModifierFix
 import org.jetbrains.plugins.groovy.lang.psi.GroovyElementVisitor
+import org.jetbrains.plugins.groovy.lang.psi.api.GrLambdaExpression
 import org.jetbrains.plugins.groovy.lang.psi.api.auxiliary.modifiers.GrModifierList
+import org.jetbrains.plugins.groovy.lang.psi.api.statements.GrVariable
+import org.jetbrains.plugins.groovy.lang.psi.api.statements.arguments.GrArgumentList
+import org.jetbrains.plugins.groovy.lang.psi.api.statements.expressions.GrAssignmentExpression
+import org.jetbrains.plugins.groovy.lang.psi.api.statements.expressions.GrParenthesizedExpression
+import org.jetbrains.plugins.groovy.lang.psi.api.statements.expressions.path.GrMethodCallExpression
 import org.jetbrains.plugins.groovy.lang.psi.api.statements.typedef.GrTypeDefinition
 
 
@@ -31,5 +38,24 @@ class GroovyAnnotator30(private val holder: AnnotationHolder) : GroovyElementVis
       registerFix(annotation, GrRemoveModifierFix(PsiModifier.DEFAULT, GroovyBundle.message("illegal.default.modifier.fix")), modifier)
     }
   }
+
+  override fun visitLambdaExpression(expression: GrLambdaExpression) {
+    checkSingleArgumentLambda(expression)
+    super.visitLambdaExpression(expression)
+  }
+
+  private fun checkSingleArgumentLambda(lambda: GrLambdaExpression) {
+    val parameterList = lambda.parameterList
+    parameterList.lParen?.let { return }
+    val parent = lambda.parent
+    when (parent) {
+      is GrAssignmentExpression, is GrVariable, is GrParenthesizedExpression -> return
+      is GrArgumentList -> if (parent.parent is GrMethodCallExpression) return
+    }
+
+    holder.createErrorAnnotation(parameterList, GroovyBundle.message("illegal.single.argument.lambda")).apply {
+      registerFix(AddParenthesisToLambdaParameterAction(lambda))
+    }
+  }
 }
 

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/annotator/intentions/AddParenthesisToLambdaParameterAction.kt

@@ -0,0 +1,47 @@
+// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package org.jetbrains.plugins.groovy.annotator.intentions
+
+import com.intellij.codeInsight.intention.IntentionAction
+import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.project.Project
+import com.intellij.psi.PsiFile
+import com.intellij.psi.SmartPsiElementPointer
+import com.intellij.psi.util.createSmartPointer
+import org.jetbrains.plugins.groovy.GroovyBundle.message
+import org.jetbrains.plugins.groovy.lang.psi.GroovyPsiElementFactory
+import org.jetbrains.plugins.groovy.lang.psi.api.GrLambdaExpression
+
+class AddParenthesisToLambdaParameterAction(parameterList: GrLambdaExpression) : IntentionAction {
+
+  private val myLambda: SmartPsiElementPointer<GrLambdaExpression> = parameterList.createSmartPointer()
+
+  override fun getText(): String = familyName
+
+  override fun getFamilyName(): String = message("add.parenthesis.to.lambda.parameter.list")
+
+  override fun startInWriteAction(): Boolean = true
+
+  override fun isAvailable(project: Project, editor: Editor?, file: PsiFile?): Boolean {
+    val parameterList = myLambda.element?.parameterList ?: return false
+    parameterList.lParen ?: return true
+    return false
+  }
+
+  override fun invoke(project: Project, editor: Editor?, file: PsiFile?) {
+    val lambda = myLambda.element ?: return
+    val closureText = closureText(lambda) ?: return
+    val closure = GroovyPsiElementFactory.getInstance(project).createLambdaFromText(closureText)
+    lambda.replaceWithExpression(closure, false)
+  }
+
+  private fun closureText(lambda: GrLambdaExpression): String? {
+    val closureText = StringBuilder()
+    closureText.append("(")
+    val parameterList = lambda.parameterList
+    appendTextBetween(closureText, parameterList.text, parameterList.lParen, parameterList.rParen)
+    closureText.append(")")
+    appendTextBetween(closureText, lambda.text, parameterList, null)
+
+    return closureText.toString()
+  }
+}

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/annotator/intentions/ConvertLambdaToClosureAction.kt

@@ -4,7 +4,6 @@ package org.jetbrains.plugins.groovy.annotator.intentions
 import com.intellij.codeInsight.intention.IntentionAction
 import com.intellij.openapi.editor.Editor
 import com.intellij.openapi.project.Project
-import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiFile
 import com.intellij.psi.SmartPsiElementPointer
 import com.intellij.psi.util.createSmartPointer
@@ -51,25 +50,4 @@ class ConvertLambdaToClosureAction(lambda: GrLambdaExpression) : IntentionAction
     closureText.append("}")
     return closureText.toString()
   }
-
-  /**
-   * Appends [text] to the [builder] cutting length of [left] text from the start and length of [right] text from the end.
-   */
-  private fun appendTextBetween(builder: StringBuilder, text: String, left: PsiElement?, right: PsiElement?) {
-    val start = left?.textLength ?: 0
-    val end = text.length - (right?.textLength ?: 0)
-    builder.append(text, start, end)
-  }
-
-  /**
-   * Appends text of elements to the [builder] between [start] and [stop].
-   * If [stop] is `null` then all siblings of [start] are processed.
-   */
-  private fun appendElements(builder: StringBuilder, start: PsiElement, stop: PsiElement) {
-    var current: PsiElement? = start.nextSibling
-    while (current !== null && current !== stop) {
-      builder.append(current.text)
-      current = current.nextSibling
-    }
-  }
 }

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/annotator/intentions/intentionUtil.kt

@@ -0,0 +1,25 @@
+// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package org.jetbrains.plugins.groovy.annotator.intentions
+
+import com.intellij.psi.PsiElement
+
+/**
+ * Appends [text] to the [builder] cutting length of [left] text from the start and length of [right] text from the end.
+ */
+internal fun appendTextBetween(builder: StringBuilder, text: String, left: PsiElement?, right: PsiElement?) {
+  val start = left?.textLength ?: 0
+  val end = text.length - (right?.textLength ?: 0)
+  builder.append(text, start, end)
+}
+
+/**
+ * Appends text of elements to the [builder] between [start] and [stop].
+ * If [stop] is `null` then all siblings of [start] are processed.
+ */
+internal fun appendElements(builder: StringBuilder, start: PsiElement, stop: PsiElement) {
+  var current: PsiElement? = start.nextSibling
+  while (current !== null && current !== stop) {
+    builder.append(current.text)
+    current = current.nextSibling
+  }
+}

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/GroovyPsiElementFactory.java

@@ -1,4 +1,4 @@
-// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.plugins.groovy.lang.psi;
 
 import com.intellij.openapi.components.ServiceManager;
@@ -11,6 +11,7 @@ import org.jetbrains.annotations.Nullable;
 import org.jetbrains.plugins.groovy.lang.groovydoc.psi.api.GrDocComment;
 import org.jetbrains.plugins.groovy.lang.groovydoc.psi.api.GrDocMemberReference;
 import org.jetbrains.plugins.groovy.lang.groovydoc.psi.api.GrDocReferenceElement;
+import org.jetbrains.plugins.groovy.lang.psi.api.GrLambdaExpression;
 import org.jetbrains.plugins.groovy.lang.psi.api.auxiliary.modifiers.GrModifierList;
 import org.jetbrains.plugins.groovy.lang.psi.api.auxiliary.modifiers.annotation.GrAnnotation;
 import org.jetbrains.plugins.groovy.lang.psi.api.auxiliary.modifiers.annotation.GrAnnotationNameValuePair;
@@ -187,6 +188,14 @@ public abstract class GroovyPsiElementFactory implements JVMElementFactory {
     return createClosureFromText(s, null);
   }
 
+  @NotNull
+  public abstract GrLambdaExpression createLambdaFromText(@NotNull String text, @Nullable PsiElement context);
+
+  @NotNull
+  public GrLambdaExpression createLambdaFromText(@NotNull String text) {
+    return createLambdaFromText(text, null);
+  }
+
   @NotNull
   public GrParameter createParameter(@NotNull String name, @Nullable String typeText, @Nullable GroovyPsiElement context) throws IncorrectOperationException {
     return createParameter(name, typeText, null, context);

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/GroovyPsiElementFactoryImpl.java

@@ -1,4 +1,4 @@
-// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.plugins.groovy.lang.psi.impl;
 
 import com.intellij.lang.ASTNode;
@@ -26,6 +26,7 @@ import org.jetbrains.plugins.groovy.lang.groovydoc.psi.api.GrDocMemberReference;
 import org.jetbrains.plugins.groovy.lang.groovydoc.psi.api.GrDocReferenceElement;
 import org.jetbrains.plugins.groovy.lang.groovydoc.psi.api.GrDocTag;
 import org.jetbrains.plugins.groovy.lang.psi.*;
+import org.jetbrains.plugins.groovy.lang.psi.api.GrLambdaExpression;
 import org.jetbrains.plugins.groovy.lang.psi.api.auxiliary.modifiers.GrModifier;
 import org.jetbrains.plugins.groovy.lang.psi.api.auxiliary.modifiers.GrModifierList;
 import org.jetbrains.plugins.groovy.lang.psi.api.auxiliary.modifiers.annotation.GrAnnotation;
@@ -361,6 +362,17 @@ public class GroovyPsiElementFactoryImpl extends GroovyPsiElementFactory {
     return ((GrClosableBlock)initializer);
   }
 
+  @NotNull
+  @Override
+  public GrLambdaExpression createLambdaFromText(@NotNull String lambdaText, PsiElement context) throws IncorrectOperationException {
+    GroovyFile psiFile = createGroovyFileChecked("def __hdsjfghkl_sdhjfshglk_foo  = " + lambdaText, false, context);
+    final GrStatement st = psiFile.getStatements()[0];
+    LOG.assertTrue(st instanceof GrVariableDeclaration, lambdaText);
+    final GrExpression initializer = ((GrVariableDeclaration)st).getVariables()[0].getInitializerGroovy();
+    LOG.assertTrue(initializer instanceof GrLambdaExpression, lambdaText);
+    return ((GrLambdaExpression)initializer);
+  }
+
   private GroovyFileImpl createDummyFile(@NotNull CharSequence text, boolean physical) {
     final String fileName = DUMMY_FILE_NAME + '.' + GroovyFileType.GROOVY_FILE_TYPE.getDefaultExtension();
     final long stamp = System.currentTimeMillis();

plugins/groovy/test/org/jetbrains/plugins/groovy/lang/highlighting/AddParenthesisToLambdaParameterTest.groovy

@@ -0,0 +1,41 @@
+// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package org.jetbrains.plugins.groovy.lang.highlighting
+
+import groovy.transform.CompileStatic
+import org.jetbrains.plugins.groovy.GroovyBundle
+import org.jetbrains.plugins.groovy.util.ActionTest
+import org.jetbrains.plugins.groovy.util.Groovy30Test
+import org.junit.Test
+
+@CompileStatic
+class AddParenthesisToLambdaParameterTest extends Groovy30Test implements ActionTest {
+
+  private void doTest(String before, String after) {
+    doActionTest(GroovyBundle.message("add.parenthesis.to.lambda.parameter.list"), before, after)
+  }
+
+  @Test
+  void 'statement expression'() {
+    doTest '<caret>a -> /*mark*/ b', '(a) -> /*mark*/ b'
+  }
+
+  @Test
+  void 'nested lambda'() {
+    doTest 'a -> <caret>b /*mark*/->  c', 'a -> (b) /*mark*/ -> c'
+  }
+
+  @Test
+  void 'multyline'() {
+    doTest '''
+true ? a<caret>a -> {
+    //line comment
+    aa++
+} :  () -> {}
+''', '''
+true ? (aa) -> {
+    //line comment
+    aa++
+} :  () -> {}
+'''
+  }
+}

plugins/groovy/test/org/jetbrains/plugins/groovy/lang/highlighting/Groovy30HighlightingTest.groovy

@@ -76,4 +76,8 @@ I i = {3}
   void 'test reassigned var in lambda 2'() {
     highlightingTest GrUnresolvedAccessInspection
   }
+
+  void 'test illegal single argument lambda'() {
+    highlightingTest ()
+  }
 }

plugins/groovy/test/org/jetbrains/plugins/groovy/util/Groovy30Test.groovy

@@ -0,0 +1,15 @@
+// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package org.jetbrains.plugins.groovy.util
+
+import com.intellij.testFramework.LightProjectDescriptor
+import groovy.transform.CompileStatic
+import org.jetbrains.plugins.groovy.GroovyProjectDescriptors
+
+@CompileStatic
+abstract class Groovy30Test extends LightProjectTest {
+
+  @Override
+  final LightProjectDescriptor getProjectDescriptor() {
+    GroovyProjectDescriptors.GROOVY_3_0
+  }
+}

plugins/groovy/testdata/highlighting/v30/illegalSingleArgumentLambda.groovy

@@ -0,0 +1,7 @@
+<error descr="Single argument form of lambda is available only as right part of assignment expression or argument inside method call">a</error> -> a
+def l = b-> <error descr="Single argument form of lambda is available only as right part of assignment expression or argument inside method call">c</error>-> d
+def l2 = false ? <error descr="Single argument form of lambda is available only as right part of assignment expression or argument inside method call">e</error>->e : <error descr="Single argument form of lambda is available only as right part of assignment expression or argument inside method call">f</error>->f
+if ((e->e) != null){}
+m(g->g)
+def l3 = h->h
+l3 = j->j