J2K: generate accessor bodies in expression form if possible

idea/src/org/jetbrains/kotlin/idea/intentions/ConvertToExpressionBodyIntention.kt

@@ -114,7 +114,7 @@ public class ConvertToExpressionBodyIntention : JetSelfTargetingOffsetIndependen
             is JetDeclaration, is JetLoopExpression -> return null // is JetExpression but does not have value
 
             else  -> {
-                if (statement is JetBinaryExpression && statement.getOperationToken() == JetTokens.EQ) return null // assignment does not have value
+                if (statement is JetBinaryExpression && statement.operationToken in JetTokens.ALL_ASSIGNMENTS) return null // assignment does not have value
                 val expressionType = statement.analyze().getType(statement) ?: return null
                 if (!KotlinBuiltIns.isUnit(expressionType) && !KotlinBuiltIns.isNothing(expressionType)) return null
                 return statement

idea/src/org/jetbrains/kotlin/idea/j2k/J2kPostProcessings.kt

@@ -52,6 +52,7 @@ object J2KPostProcessingRegistrar {
         _processings.add(ConvertToStringTemplateProcessing())
         _processings.add(UsePropertyAccessSyntaxProcessing())
         _processings.add(RemoveRedundantSamAdaptersProcessing())
+        _processings.add(AccessorBodyToExpression())
 
         registerIntentionBasedProcessing(IfThenToSafeAccessIntention()) { applyTo(it) }
         registerIntentionBasedProcessing(IfThenToElvisIntention()) { applyTo(it) }
@@ -192,4 +193,14 @@ object J2KPostProcessingRegistrar {
             }
         }
     }
+
+    private class AccessorBodyToExpression : J2kPostProcessing {
+        private val intention = ConvertToExpressionBodyIntention()
+
+        override fun createAction(element: JetElement, diagnostics: Diagnostics): (() -> Unit)? {
+            if (element !is JetPropertyAccessor) return null
+            if (!intention.isApplicableTo(element)) return null
+            return { intention.applyTo(element, true) }
+        }
+    }
 }

idea/testData/intentions/convertToExpressionBody/assignPlus.kt

@@ -0,0 +1,7 @@
+// IS_APPLICABLE: false
+
+var x = 0
+
+fun <caret>foo() {
+    x += 1
+}

idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java

@@ -4027,6 +4027,12 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("assignPlus.kt")
+        public void testAssignPlus() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/intentions/convertToExpressionBody/assignPlus.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("assignment.kt")
         public void testAssignment() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/intentions/convertToExpressionBody/assignment.kt");

j2k/src/org/jetbrains/kotlin/j2k/Converter.kt

@@ -347,7 +347,7 @@ class Converter private constructor(
                     getter = PropertyAccessor(AccessorKind.GETTER, method.annotations, Modifiers.Empty, method.parameterList, method.body)
                     getter.assignPrototype(getMethod, CommentsAndSpacesInheritance.NO_SPACES)
                 }
-                else if (propertyInfo.isOverride) { //TODO: expression body!
+                else if (propertyInfo.isOverride) {
                     val superExpression = SuperExpression(Identifier.Empty).assignNoPrototype()
                     val superAccess = QualifiedExpression(superExpression, propertyInfo.identifier).assignNoPrototype()
                     val returnStatement = ReturnStatement(superAccess).assignNoPrototype()
@@ -372,7 +372,7 @@ class Converter private constructor(
                             method.body)
                     setter.assignPrototype(setMethod, CommentsAndSpacesInheritance.NO_SPACES)
                 }
-                else if (propertyInfo.isOverride) { //TODO: expression body!
+                else if (propertyInfo.isOverride) {
                     val superExpression = SuperExpression(Identifier.Empty).assignNoPrototype()
                     val superAccess = QualifiedExpression(superExpression, propertyInfo.identifier).assignNoPrototype()
                     val valueIdentifier = Identifier("value", false).assignNoPrototype()

j2k/testData/fileOrElement/callChainExpression/libraryMethodCall.kt

@@ -3,9 +3,7 @@ internal object Library {
     }
 
     val string: String
-        get() {
-            return ""
-        }
+        get() = ""
 }
 
 internal class User {

j2k/testData/fileOrElement/callChainExpression/libraryMethodCallFromInstance-settings.kt

@@ -5,9 +5,7 @@ internal class Library {
     }
 
     val string: String?
-        get() {
-            return ""
-        }
+        get() = ""
 }
 
 internal class User {

j2k/testData/fileOrElement/callChainExpression/libraryMethodCallFromInstance.kt

@@ -3,9 +3,7 @@ internal class Library {
     }
 
     val string: String
-        get() {
-            return ""
-        }
+        get() = ""
 }
 
 internal class User {

j2k/testData/fileOrElement/dropAccessors/GetterTypeNotMatch.kt

@@ -3,7 +3,5 @@ internal class A {
     private val s: String? = null
 
     val value: Any
-        get() {
-            return s
-        }
-}
+        get() = s
+}

j2k/testData/fileOrElement/dropAccessors/Overrides.kt

@@ -22,28 +22,20 @@ internal interface I1 : I {
 
 internal open class B {
     open val fromB1: String
-        get() {
-            return ""
-        }
+        get() = ""
 
     open var fromB2: String
-        get() {
-            return ""
-        }
+        get() = ""
         set(value: String) {
         }
 
     open var fromB3: String
-        get() {
-            return ""
-        }
+        get() = ""
         set(value: String) {
         }
 
     open var fromB4: String
-        get() {
-            return ""
-        }
+        get() = ""
         set(value: String) {
         }
 
@@ -55,29 +47,21 @@ internal abstract class C(override val something1: Int) : B(), I {
     private var mySomething6: Int = 0
 
     override val something2: Int
-        get() {
-            return 0
-        }
+        get() = 0
 
     override var something3: Int
-        get() {
-            return 0
-        }
+        get() = 0
         set(value: Int) {
         }
 
     override var something4: Int
-        get() {
-            return 0
-        }
+        get() = 0
         set(value: Int) {
             super.something4 = value
         }
 
     override var something5: Int
-        get() {
-            return super.something5
-        }
+        get() = super.something5
         set(value: Int) {
 
         }
@@ -91,38 +75,28 @@ internal abstract class C(override val something1: Int) : B(), I {
     }
 
     override val fromB1: String
-        get() {
-            return super.fromB1
-        }
+        get() = super.fromB1
 
     override var fromB2: String
-        get() {
-            return super.fromB2
-        }
+        get() = super.fromB2
         set(value: String) {
             super.fromB2 = value
         }
 
     override var fromB3: String
-        get() {
-            return super.fromB3
-        }
+        get() = super.fromB3
         set(value: String) {
             super.fromB3 = value
         }
 
     override var fromB4: String
-        get() {
-            return super.fromB4
-        }
+        get() = super.fromB4
         set(value: String) {
             super.fromB4 = value
         }
 
     val fromB5: String
-        get() {
-            return ""
-        }
+        get() = ""
 
     override fun setFromB5(value: String) {
         super.setFromB5(value)

j2k/testData/fileOrElement/dropAccessors/OverridesOfExternalCode.kt

@@ -4,41 +4,31 @@ import javaApi.JavaClassDerivedFromKotlinClassWithProperties
 
 internal open class A : KotlinClassWithProperties() {
     override var someVar1: String
-        get() {
-            return super.someVar1
-        }
+        get() = super.someVar1
         set(s: String) {
             super.someVar1 = s
         }
 
     override var someVar2: String
-        get() {
-            return super.someVar2
-        }
+        get() = super.someVar2
         set(value: String) {
             super.someVar2 = value
         }
 
     override var someVar3: String
-        get() {
-            return super.someVar3
-        }
+        get() = super.someVar3
         set(s: String) {
             super.someVar3 = s
         }
 
     override var someVar4: String
-        get() {
-            return super.someVar4
-        }
+        get() = super.someVar4
         set(value: String) {
             super.someVar4 = value
         }
 
     override val someVal: String
-        get() {
-            return super.someVal
-        }
+        get() = super.someVal
 
     override fun getSomething1() {
         super.getSomething1()
@@ -85,9 +75,7 @@ internal class B : JavaClassWithProperties() {
 
 internal class C : A() {
     override var someVar1: String
-        get() {
-            return super.someVar1
-        }
+        get() = super.someVar1
         set(value: String) {
             super.someVar1 = value
         }
@@ -95,17 +83,13 @@ internal class C : A() {
 
 internal class D : JavaClassDerivedFromKotlinClassWithProperties() {
     override var someVar1: String
-        get() {
-            return "a"
-        }
+        get() = "a"
         set(value: String) {
             super.someVar1 = value
         }
 
     override var someVar2: String
-        get() {
-            return super.someVar2
-        }
+        get() = super.someVar2
         set(value: String) {
         }
 

j2k/testData/fileOrElement/field/conversion.kt

@@ -8,8 +8,6 @@ internal class A {
     companion object {
 
         val byte: Byte
-            get() {
-                return 0
-            }
+            get() = 0
     }
 }

j2k/testData/fileOrElement/function/final.kt

@@ -1,4 +1,2 @@
 val string: String
-    get() {
-        return ""
-    }
+    get() = ""

j2k/testData/fileOrElement/function/methodWithReturnStatement.kt

@@ -1,4 +1,2 @@
 val isTrue: Boolean
-    get() {
-        return true
-    }
+    get() = true

j2k/testData/fileOrElement/function/open.kt

@@ -1,4 +1,2 @@
 val string: String
-    get() {
-        return ""
-    }
+    get() = ""

j2k/testData/fileOrElement/returnStatement/currentMethodBug.kt

@@ -7,9 +7,7 @@ internal class C {
         get() {
             foo(object : I {
                 override val int: Int
-                    get() {
-                        return 0
-                    }
+                    get() = 0
             })
             return string
         }