J2K: don't automatically convert Java code when pasting to a string literal in Kotlin

#KT-7759 Fixed

idea/src/org/jetbrains/kotlin/idea/conversion/copy/ConvertJavaCopyPastePostProcessor.kt

@@ -29,6 +29,7 @@ import com.intellij.psi.PsiDocumentManager
 import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiFile
 import com.intellij.psi.PsiJavaFile
+import com.intellij.psi.util.PsiTreeUtil
 import org.jetbrains.annotations.TestOnly
 import org.jetbrains.kotlin.idea.caches.resolve.resolveImportReference
 import org.jetbrains.kotlin.idea.codeInsight.KotlinCopyPasteReferenceProcessor
@@ -43,8 +44,9 @@ import org.jetbrains.kotlin.j2k.ConverterSettings
 import org.jetbrains.kotlin.j2k.JavaToKotlinConverter
 import org.jetbrains.kotlin.j2k.ParseContext
 import org.jetbrains.kotlin.name.FqName
-import org.jetbrains.kotlin.psi.KtFile
-import org.jetbrains.kotlin.psi.KtPsiFactory
+import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.psiUtil.parents
+import org.jetbrains.kotlin.utils.addToStdlib.firstIsInstanceOrNull
 import java.awt.datatransfer.Transferable
 import java.util.*
 
@@ -80,6 +82,11 @@ public class ConvertJavaCopyPastePostProcessor : CopyPastePostProcessor<TextBloc
         val document = editor.getDocument()
         val targetFile = PsiDocumentManager.getInstance(project).getPsiFile(document) as? KtFile ?: return
 
+        val elementAt = targetFile.findElementAt(caretOffset)
+        if (PsiTreeUtil.getParentOfType(elementAt, KtStringTemplateExpression::class.java, false, KtStringTemplateEntryWithExpression::class.java) is KtStringTemplateExpression) {
+            return
+        }
+
         data class Result(val text: String?, val referenceData: Collection<KotlinReferenceData>, val explicitImports: Set<FqName>)
 
         fun doConversion(): Result {

idea/testData/copyPaste/conversion/InsertIntoString.expected.kt

@@ -0,0 +1,3 @@
+fun main(args: Array<String>) {
+    println("String s = 1;")
+}

idea/testData/copyPaste/conversion/InsertIntoString.java

@@ -0,0 +1,7 @@
+class A {
+    public static void main(String[] args) {
+        <selection>String s = 1;</selection>
+    }
+}
+
+// NO_CONVERSION_EXPECTED

idea/testData/copyPaste/conversion/InsertIntoString.to.kt

@@ -0,0 +1,3 @@
+fun main(args: Array<String>) {
+    println("<caret>")
+}

idea/tests/org/jetbrains/kotlin/idea/conversion/copy/JavaToKotlinCopyPasteConversionTestGenerated.java

@@ -173,6 +173,12 @@ public class JavaToKotlinCopyPasteConversionTestGenerated extends AbstractJavaTo
         doTest(fileName);
     }
 
+    @TestMetadata("InsertIntoString.java")
+    public void testInsertIntoString() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/copyPaste/conversion/InsertIntoString.java");
+        doTest(fileName);
+    }
+
     @TestMetadata("MethodDeclarationWithNoBody.java")
     public void testMethodDeclarationWithNoBody() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/copyPaste/conversion/MethodDeclarationWithNoBody.java");