From a662d777e8b371cf2e344f78c9938f84b91727cf Mon Sep 17 00:00:00 2001
From: shiraji <isogai.shiraji@gmail.com>
Date: Fri, 28 Oct 2016 14:45:56 +0900
Subject: [PATCH] Implement "Remove redundant '.let' call" binary operator
 support #KT-14396 Fixed

---
 .../org/jetbrains/kotlin/psi/KtPsiFactory.kt  |  3 +
 .../ReplaceSingleLineLetIntention.kt          | 85 ++++++++++++++++---
 .../lambdaWithBinaryExpression.kt             |  6 ++
 .../lambdaWithBinaryExpression2.kt            |  6 ++
 .../letUseItAsParamWithBinaryExpression.kt    |  6 ++
 .../letUseItWithBinaryExpression.kt           |  6 ++
 .../letUseItWithBinaryExpression2.kt          |  6 ++
 .../letWithBinaryExpression.kt                |  6 ++
 .../letWithBinaryExpression.kt.after          |  6 ++
 .../letWithSimpleBinaryExpression.kt          |  6 ++
 .../letWithSimpleBinaryExpression.kt.after    |  6 ++
 .../letWithThisBinaryExpression.kt            |  6 ++
 .../letWithThisBinaryExpression.kt.after      |  6 ++
 .../letWithThisShortBinaryExpression.kt       |  6 ++
 .../letWithThisShortBinaryExpression.kt.after |  6 ++
 .../intentions/IntentionTestGenerated.java    | 54 ++++++++++++
 16 files changed, 208 insertions(+), 12 deletions(-)
 create mode 100644 idea/testData/intentions/replaceSingleLineLetIntention/lambdaWithBinaryExpression.kt
 create mode 100644 idea/testData/intentions/replaceSingleLineLetIntention/lambdaWithBinaryExpression2.kt
 create mode 100644 idea/testData/intentions/replaceSingleLineLetIntention/letUseItAsParamWithBinaryExpression.kt
 create mode 100644 idea/testData/intentions/replaceSingleLineLetIntention/letUseItWithBinaryExpression.kt
 create mode 100644 idea/testData/intentions/replaceSingleLineLetIntention/letUseItWithBinaryExpression2.kt
 create mode 100644 idea/testData/intentions/replaceSingleLineLetIntention/letWithBinaryExpression.kt
 create mode 100644 idea/testData/intentions/replaceSingleLineLetIntention/letWithBinaryExpression.kt.after
 create mode 100644 idea/testData/intentions/replaceSingleLineLetIntention/letWithSimpleBinaryExpression.kt
 create mode 100644 idea/testData/intentions/replaceSingleLineLetIntention/letWithSimpleBinaryExpression.kt.after
 create mode 100644 idea/testData/intentions/replaceSingleLineLetIntention/letWithThisBinaryExpression.kt
 create mode 100644 idea/testData/intentions/replaceSingleLineLetIntention/letWithThisBinaryExpression.kt.after
 create mode 100644 idea/testData/intentions/replaceSingleLineLetIntention/letWithThisShortBinaryExpression.kt
 create mode 100644 idea/testData/intentions/replaceSingleLineLetIntention/letWithThisShortBinaryExpression.kt.after

diff --git a/compiler/frontend/src/org/jetbrains/kotlin/psi/KtPsiFactory.kt b/compiler/frontend/src/org/jetbrains/kotlin/psi/KtPsiFactory.kt
index f126a222be5..d580bf72710 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/psi/KtPsiFactory.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/psi/KtPsiFactory.kt
@@ -78,6 +78,9 @@ class KtPsiFactory(private val project: Project) {
         return if (expression.text == text) expression else null
     }
 
+    fun createThisExpression() =
+                (createExpression("this.x") as KtQualifiedExpression).receiverExpression as KtThisExpression
+
     fun createClassLiteral(className: String): KtClassLiteralExpression =
             createExpression("$className::class") as KtClassLiteralExpression
 
diff --git a/idea/src/org/jetbrains/kotlin/idea/intentions/ReplaceSingleLineLetIntention.kt b/idea/src/org/jetbrains/kotlin/idea/intentions/ReplaceSingleLineLetIntention.kt
index 8bba28a66f6..f214890da55 100644
--- a/idea/src/org/jetbrains/kotlin/idea/intentions/ReplaceSingleLineLetIntention.kt
+++ b/idea/src/org/jetbrains/kotlin/idea/intentions/ReplaceSingleLineLetIntention.kt
@@ -31,18 +31,49 @@ class ReplaceSingleLineLetIntention : SelfTargetingOffsetIndependentIntention<Kt
         "Remove redundant '.let' call"
 ) {
     override fun applyTo(element: KtCallExpression, editor: Editor?) {
-        val lambdaExpression = element.lambdaArguments.firstOrNull()?.getLambdaExpression() ?: return
-        val bodyExpression = lambdaExpression.bodyExpression?.children?.singleOrNull() ?: return
-        val dotQualifiedExpression = bodyExpression as? KtDotQualifiedExpression ?: return
+        element.lambdaArguments.firstOrNull()?.getLambdaExpression()?.bodyExpression?.children?.singleOrNull()?.let {
+            when (it) {
+                is KtDotQualifiedExpression -> it.applyTo(element)
+                is KtBinaryExpression -> it.applyTo(element)
+            }
+        }
+    }
+
+    private fun KtBinaryExpression.applyTo(element: KtCallExpression) {
+        val left = left ?: return
+        val factory = KtPsiFactory(element.project)
+        val parent = element.parent
+        when (parent) {
+            is KtQualifiedExpression -> {
+                val receiver = parent.receiverExpression
+                val newLeft = when (left) {
+                    is KtDotQualifiedExpression -> left.replaceFirstReceiver(factory, receiver, parent is KtSafeQualifiedExpression)
+                    else -> receiver
+                }
+                val newExpression = factory.createExpressionByPattern("$0 $1 $2", newLeft, operationReference, right!!)
+                parent.replace(newExpression)
+            }
+            else -> {
+                val newLeft = when (left) {
+                    is KtDotQualifiedExpression -> left.deleteFirstReceiver()
+                    else -> factory.createThisExpression()
+                }
+                val newExpression = factory.createExpressionByPattern("$0 $1 $2", newLeft, operationReference, right!!)
+                element.replace(newExpression)
+            }
+        }
+    }
+
+    private fun KtDotQualifiedExpression.applyTo(element: KtCallExpression) {
         val parent = element.parent
         when (parent) {
             is KtQualifiedExpression -> {
                 val factory = KtPsiFactory(element.project)
                 val receiver = parent.receiverExpression
-                parent.replace(dotQualifiedExpression.replaceFirstReceiver(factory, receiver, parent.operationSign == KtTokens.SAFE_ACCESS))
+                parent.replace(replaceFirstReceiver(factory, receiver, parent is KtSafeQualifiedExpression))
             }
             else -> {
-                element.replace(dotQualifiedExpression.deleteFirstReceiver())
+                element.replace(deleteFirstReceiver())
             }
         }
     }
@@ -59,17 +90,47 @@ class ReplaceSingleLineLetIntention : SelfTargetingOffsetIndependentIntention<Kt
     override fun isApplicableTo(element: KtCallExpression): Boolean {
         if (!isLetMethod(element)) return false
         val lambdaExpression = element.lambdaArguments.firstOrNull()?.getLambdaExpression() ?: return false
-        val bodyExpression = lambdaExpression.bodyExpression?.children?.singleOrNull() ?: return false
-        val dotQualifiedExpression = bodyExpression as? KtDotQualifiedExpression ?: return false
         val parameterName = lambdaExpression.getParameterName() ?: return false
-        val receiverExpression = dotQualifiedExpression.getLeftMostReceiverExpression()
-        if (receiverExpression.text != parameterName) return false
-        dotQualifiedExpression.selectorExpression?.let {
-            if (it.anyDescendantOfType<KtLambdaExpression>()) return false
+        val bodyExpression = lambdaExpression.bodyExpression?.children?.singleOrNull() ?: return false
+
+        return when (bodyExpression) {
+            is KtBinaryExpression -> bodyExpression.isApplicable(parameterName)
+            is KtDotQualifiedExpression -> bodyExpression.isApplicable(parameterName)
+            else -> false
         }
-        return !dotQualifiedExpression.receiverUsedAsArgument(parameterName)
     }
 
+    private fun KtBinaryExpression.isApplicable(parameterName: String): Boolean {
+        val left = left ?: return false
+        when (left) {
+            is KtNameReferenceExpression -> if (left.text != parameterName) return false
+            is KtDotQualifiedExpression -> if (!left.isApplicable(parameterName)) return false
+        }
+
+        val right = right ?: return false
+        when (right) {
+            is KtNameReferenceExpression -> return right.text != parameterName
+            is KtDotQualifiedExpression -> {
+                if (right.isParameterLeftMostReceiver(parameterName)) return false
+                if (right.hasLambdaExpression()) return false
+                return !right.receiverUsedAsArgument(parameterName)
+            }
+            else -> return true
+        }
+    }
+
+    private fun KtDotQualifiedExpression.isApplicable(parameterName: String): Boolean {
+        if (!isParameterLeftMostReceiver(parameterName)) return false
+        if (hasLambdaExpression()) return false
+        return !receiverUsedAsArgument(parameterName)
+    }
+
+    private fun KtDotQualifiedExpression.hasLambdaExpression()
+            = selectorExpression?.anyDescendantOfType<KtLambdaExpression>() ?: false
+
+    private fun KtDotQualifiedExpression.isParameterLeftMostReceiver(parameterName: String)
+            = getLeftMostReceiverExpression().text == parameterName
+
     private fun isLetMethod(element: KtCallExpression) =
             element.calleeExpression?.text == "let" && element.isMethodCall("kotlin.let")
 
diff --git a/idea/testData/intentions/replaceSingleLineLetIntention/lambdaWithBinaryExpression.kt b/idea/testData/intentions/replaceSingleLineLetIntention/lambdaWithBinaryExpression.kt
new file mode 100644
index 00000000000..23db56267bc
--- /dev/null
+++ b/idea/testData/intentions/replaceSingleLineLetIntention/lambdaWithBinaryExpression.kt
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: false
+
+fun baz(foo: String) {
+    foo.let<caret> { it.indexOfLast { c -> c == it[0] } + 1 }
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/replaceSingleLineLetIntention/lambdaWithBinaryExpression2.kt b/idea/testData/intentions/replaceSingleLineLetIntention/lambdaWithBinaryExpression2.kt
new file mode 100644
index 00000000000..67e99fb1e30
--- /dev/null
+++ b/idea/testData/intentions/replaceSingleLineLetIntention/lambdaWithBinaryExpression2.kt
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: false
+
+fun baz(foo: String) {
+    foo.let<caret> { it.length + "".indexOfLast { c -> c == it[0] } }
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/replaceSingleLineLetIntention/letUseItAsParamWithBinaryExpression.kt b/idea/testData/intentions/replaceSingleLineLetIntention/letUseItAsParamWithBinaryExpression.kt
new file mode 100644
index 00000000000..61609c11507
--- /dev/null
+++ b/idea/testData/intentions/replaceSingleLineLetIntention/letUseItAsParamWithBinaryExpression.kt
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: false
+
+fun foo() {
+    "".let<caret> { it.length + "".indexOf(it) }
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/replaceSingleLineLetIntention/letUseItWithBinaryExpression.kt b/idea/testData/intentions/replaceSingleLineLetIntention/letUseItWithBinaryExpression.kt
new file mode 100644
index 00000000000..5b207566566
--- /dev/null
+++ b/idea/testData/intentions/replaceSingleLineLetIntention/letUseItWithBinaryExpression.kt
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: false
+
+fun foo() {
+    "".let<caret> { it.length + it.length }
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/replaceSingleLineLetIntention/letUseItWithBinaryExpression2.kt b/idea/testData/intentions/replaceSingleLineLetIntention/letUseItWithBinaryExpression2.kt
new file mode 100644
index 00000000000..25d349fdf99
--- /dev/null
+++ b/idea/testData/intentions/replaceSingleLineLetIntention/letUseItWithBinaryExpression2.kt
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: false
+
+fun foo() {
+    "".let<caret> { it.substring(0, 1) + it }
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/replaceSingleLineLetIntention/letWithBinaryExpression.kt b/idea/testData/intentions/replaceSingleLineLetIntention/letWithBinaryExpression.kt
new file mode 100644
index 00000000000..9a57302c24b
--- /dev/null
+++ b/idea/testData/intentions/replaceSingleLineLetIntention/letWithBinaryExpression.kt
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: true
+
+fun foo() {
+    "".let<caret> { it.length + 1 }
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/replaceSingleLineLetIntention/letWithBinaryExpression.kt.after b/idea/testData/intentions/replaceSingleLineLetIntention/letWithBinaryExpression.kt.after
new file mode 100644
index 00000000000..8bcd30515f3
--- /dev/null
+++ b/idea/testData/intentions/replaceSingleLineLetIntention/letWithBinaryExpression.kt.after
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: true
+
+fun foo() {
+    "".length + 1
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/replaceSingleLineLetIntention/letWithSimpleBinaryExpression.kt b/idea/testData/intentions/replaceSingleLineLetIntention/letWithSimpleBinaryExpression.kt
new file mode 100644
index 00000000000..61e653185a0
--- /dev/null
+++ b/idea/testData/intentions/replaceSingleLineLetIntention/letWithSimpleBinaryExpression.kt
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: true
+
+fun foo() {
+    "".let<caret> { it + 1 }
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/replaceSingleLineLetIntention/letWithSimpleBinaryExpression.kt.after b/idea/testData/intentions/replaceSingleLineLetIntention/letWithSimpleBinaryExpression.kt.after
new file mode 100644
index 00000000000..3ae32ba8c97
--- /dev/null
+++ b/idea/testData/intentions/replaceSingleLineLetIntention/letWithSimpleBinaryExpression.kt.after
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: true
+
+fun foo() {
+    "" + 1
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/replaceSingleLineLetIntention/letWithThisBinaryExpression.kt b/idea/testData/intentions/replaceSingleLineLetIntention/letWithThisBinaryExpression.kt
new file mode 100644
index 00000000000..2c3fc8bccb0
--- /dev/null
+++ b/idea/testData/intentions/replaceSingleLineLetIntention/letWithThisBinaryExpression.kt
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: true
+
+fun Int.foo() {
+    let<caret> { it.dec() + 1 }
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/replaceSingleLineLetIntention/letWithThisBinaryExpression.kt.after b/idea/testData/intentions/replaceSingleLineLetIntention/letWithThisBinaryExpression.kt.after
new file mode 100644
index 00000000000..413570fd47d
--- /dev/null
+++ b/idea/testData/intentions/replaceSingleLineLetIntention/letWithThisBinaryExpression.kt.after
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: true
+
+fun Int.foo() {
+    dec() + 1
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/replaceSingleLineLetIntention/letWithThisShortBinaryExpression.kt b/idea/testData/intentions/replaceSingleLineLetIntention/letWithThisShortBinaryExpression.kt
new file mode 100644
index 00000000000..f05639c5168
--- /dev/null
+++ b/idea/testData/intentions/replaceSingleLineLetIntention/letWithThisShortBinaryExpression.kt
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: true
+
+fun Int.foo() {
+    let<caret> { it + 1 }
+}
\ No newline at end of file
diff --git a/idea/testData/intentions/replaceSingleLineLetIntention/letWithThisShortBinaryExpression.kt.after b/idea/testData/intentions/replaceSingleLineLetIntention/letWithThisShortBinaryExpression.kt.after
new file mode 100644
index 00000000000..21e066415dd
--- /dev/null
+++ b/idea/testData/intentions/replaceSingleLineLetIntention/letWithThisShortBinaryExpression.kt.after
@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: true
+
+fun Int.foo() {
+    this + 1
+}
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java b/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
index 53bde42d3f9..f1af0a0dfbc 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
+++ b/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
@@ -11799,6 +11799,18 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/intentions/replaceSingleLineLetIntention"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), TargetBackend.ANY, true);
         }
 
+        @TestMetadata("lambdaWithBinaryExpression.kt")
+        public void testLambdaWithBinaryExpression() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/lambdaWithBinaryExpression.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("lambdaWithBinaryExpression2.kt")
+        public void testLambdaWithBinaryExpression2() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/lambdaWithBinaryExpression2.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("let.kt")
         public void testLet() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/let.kt");
@@ -11835,6 +11847,24 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("letUseItAsParamWithBinaryExpression.kt")
+        public void testLetUseItAsParamWithBinaryExpression() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/letUseItAsParamWithBinaryExpression.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("letUseItWithBinaryExpression.kt")
+        public void testLetUseItWithBinaryExpression() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/letUseItWithBinaryExpression.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("letUseItWithBinaryExpression2.kt")
+        public void testLetUseItWithBinaryExpression2() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/letUseItWithBinaryExpression2.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("letUseItWithMultipleMethodCall1.kt")
         public void testLetUseItWithMultipleMethodCall1() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/letUseItWithMultipleMethodCall1.kt");
@@ -11859,6 +11889,12 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("letWithBinaryExpression.kt")
+        public void testLetWithBinaryExpression() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/letWithBinaryExpression.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("letWithMethodCall.kt")
         public void testLetWithMethodCall() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/letWithMethodCall.kt");
@@ -11877,6 +11913,24 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("letWithSimpleBinaryExpression.kt")
+        public void testLetWithSimpleBinaryExpression() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/letWithSimpleBinaryExpression.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("letWithThisBinaryExpression.kt")
+        public void testLetWithThisBinaryExpression() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/letWithThisBinaryExpression.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("letWithThisShortBinaryExpression.kt")
+        public void testLetWithThisShortBinaryExpression() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/letWithThisShortBinaryExpression.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("multipleReceiver.kt")
         public void testMultipleReceiver() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/multipleReceiver.kt");