[kotlin] Backtick only uncommon package name parts

#KTIJ-30095

GitOrigin-RevId: 15c6498a403d35777158263e21e482502bee058e

plugins/kotlin/code-insight/utils/src/org/jetbrains/kotlin/idea/codeinsight/utils/AddQualifiersUtil.kt

@@ -30,7 +30,6 @@ import org.jetbrains.kotlin.psi.KtPsiFactory
 import org.jetbrains.kotlin.psi.KtUserType
 import org.jetbrains.kotlin.psi.createExpressionByPattern
 import org.jetbrains.kotlin.psi.psiUtil.getPrevSiblingIgnoringWhitespaceAndComments
-import org.jetbrains.kotlin.psi.psiUtil.isIdentifier
 import org.jetbrains.kotlin.psi.psiUtil.quoteIfNeeded
 import java.lang.RuntimeException
 
@@ -91,7 +90,7 @@ object AddQualifiersUtil {
                 is KtCallableReferenceExpression -> addOrReplaceQualifier(psiFactory, parent, qualifier)
                 is KtCallExpression -> replaceExpressionWithDotQualifier(psiFactory, parent, qualifier)
                 is KtUserType -> addQualifierToType(psiFactory, parent, qualifier)
-                else -> replaceExpressionWithQualifier(psiFactory, referenceExpression, fqName)
+                else -> replaceExpressionWithQualifier(psiFactory, referenceExpression, qualifier, fqName)
             }
         }
         if (referenceExpression.isPhysical) {
@@ -148,20 +147,13 @@ object AddQualifiersUtil {
     private fun replaceExpressionWithQualifier(
         psiFactory: KtPsiFactory,
         referenceExpression: KtNameReferenceExpression,
+        packageQualifier: String,
         fqName: FqName
     ): KtElement {
         val fqNameUnsafe = fqName.toUnsafe()
         val shortName = fqNameUnsafe.shortName().asString().quoteIfNeeded()
-        val parent = fqNameUnsafe.parent()
-        val parentQuotedIfNeeded =
-            if (parent.isRoot) {
-                ""
-            } else {
-                val quotesAreNeeded = parent.pathSegments().any { !it.identifier.isIdentifier() }
-                val asString = parent.asString()
-                "${if (quotesAreNeeded) asString.quoteIfNeeded() else asString}."
-            }
-        val expressionWithQualifier = psiFactory.createExpression(parentQuotedIfNeeded + shortName)
+        val packageSeparator = ".".takeUnless { packageQualifier.isEmpty() } ?: ""
+        val expressionWithQualifier = psiFactory.createExpression(packageQualifier + packageSeparator + shortName)
         return referenceExpression.replace(expressionWithQualifier) as KtElement
     }
 }

plugins/kotlin/idea/tests/testData/intentions/addFullQualifier/callExpressions/BacktickedPackageName.kt

@@ -2,7 +2,7 @@
 package foo.`b ar`
 
 object Clazz {
-    val foo = 0
+    val zoo = 0
 }
 
-fun Clazz.foo() = <caret>Clazz.foo
+fun Clazz.zoo() = <caret>Clazz.zoo

plugins/kotlin/idea/tests/testData/intentions/addFullQualifier/callExpressions/BacktickedPackageName.kt.after

@@ -2,7 +2,7 @@
 package foo.`b ar`
 
 object Clazz {
-    val foo = 0
+    val zoo = 0
 }
 
-fun Clazz.foo() = `foo.b ar`.Clazz.foo
+fun Clazz.zoo() = foo.`b ar`.Clazz.zoo

plugins/kotlin/idea/tests/testData/intentions/addFullQualifier/callExpressions/BacktickedPackageNameAndClass.kt

@@ -2,7 +2,7 @@
 package foo.`b ar`
 
 object `Cla zz` {
-    val foo = 0
+    val zoo = 0
 }
 
-fun `Cla zz`.foo() = <caret>`Cla zz`.foo
+fun `Cla zz`.zoo() = <caret>`Cla zz`.zoo

plugins/kotlin/idea/tests/testData/intentions/addFullQualifier/callExpressions/BacktickedPackageNameAndClass.kt.after

@@ -2,7 +2,7 @@
 package foo.`b ar`
 
 object `Cla zz` {
-    val foo = 0
+    val zoo = 0
 }
 
-fun `Cla zz`.foo() = `foo.b ar`.`Cla zz`.foo
+fun `Cla zz`.zoo() = foo.`b ar`.`Cla zz`.zoo