From b9b5e07820b2adc623a329d9f0d62b6cada34743 Mon Sep 17 00:00:00 2001
From: Toshiaki Kameyama <kmymtsak@gmail.com>
Date: Sun, 6 Sep 2020 20:37:14 +0900
Subject: [PATCH] StringTemplateRule: don't report when template expression is
 keyword (#888)

---
 .../ktlint/ruleset/standard/StringTemplateRule.kt     |  7 +++++++
 .../test/resources/spec/string-template/lint.kt.spec  | 11 +++++++++++
 2 files changed, 18 insertions(+)

diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/StringTemplateRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/StringTemplateRule.kt
index 858a648899..27b779f99a 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/StringTemplateRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/StringTemplateRule.kt
@@ -9,6 +9,10 @@ import com.pinterest.ktlint.core.ast.ElementType.LONG_STRING_TEMPLATE_ENTRY
 import com.pinterest.ktlint.core.ast.ElementType.SUPER_EXPRESSION
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
 import org.jetbrains.kotlin.com.intellij.psi.impl.source.tree.LeafPsiElement
+import org.jetbrains.kotlin.psi.KtBlockStringTemplateEntry
+import org.jetbrains.kotlin.psi.KtDotQualifiedExpression
+import org.jetbrains.kotlin.psi.KtNameReferenceExpression
+import org.jetbrains.kotlin.psi.KtThisExpression
 
 class StringTemplateRule : Rule("string-template") {
 
@@ -30,6 +34,7 @@ class StringTemplateRule : Rule("string-template") {
             }
 */
         if (elementType == LONG_STRING_TEMPLATE_ENTRY) {
+            var entryExpression = (node.psi as? KtBlockStringTemplateEntry)?.expression
             val entryStart = node.firstChildNode
             val dotQualifiedExpression = entryStart.treeNext
             if (dotQualifiedExpression?.elementType == DOT_QUALIFIED_EXPRESSION) {
@@ -41,6 +46,7 @@ class StringTemplateRule : Rule("string-template") {
                 ) {
                     emit(dot.startOffset, "Redundant \"toString()\" call in string template", true)
                     if (autoCorrect) {
+                        entryExpression = (entryExpression as? KtDotQualifiedExpression)?.receiverExpression
                         node.removeChild(dot)
                         node.removeChild(callExpression)
                     }
@@ -48,6 +54,7 @@ class StringTemplateRule : Rule("string-template") {
             }
             if (node.text.startsWith("${'$'}{") &&
                 node.text.let { it.substring(2, it.length - 1) }.all { it.isPartOfIdentifier() } &&
+                (entryExpression is KtNameReferenceExpression || entryExpression is KtThisExpression) &&
                 node.treeNext.let { nextSibling ->
                     nextSibling.elementType == CLOSING_QUOTE ||
                         (
diff --git a/ktlint-ruleset-standard/src/test/resources/spec/string-template/lint.kt.spec b/ktlint-ruleset-standard/src/test/resources/spec/string-template/lint.kt.spec
index 0ac10e805c..7e6cb5e352 100644
--- a/ktlint-ruleset-standard/src/test/resources/spec/string-template/lint.kt.spec
+++ b/ktlint-ruleset-standard/src/test/resources/spec/string-template/lint.kt.spec
@@ -50,6 +50,16 @@ class E {
     override fun toString(): String = "${s0}"
 }
 
+class F {
+    fun keyword() {
+        println("${this}")
+        println("${this@F}")
+        println("${null}")
+        println("${true}")
+        println("${false}")
+    }
+}
+
 // expect
 // 2:29:Redundant "toString()" call in string template
 // 3:28:Redundant "toString()" call in string template
@@ -57,3 +67,4 @@ class E {
 // 7:15:Redundant curly braces
 // 28:79:Redundant "toString()" call in string template
 // 45:20:Redundant curly braces
+// 55:19:Redundant curly braces