Correctly honor expected type when converting string templates to UAST

#KT-17315 Fixed
 #KT-17316 Fixed

plugins/uast-kotlin/src/org/jetbrains/uast/kotlin/KotlinUastLanguagePlugin.kt

@@ -250,15 +250,28 @@ internal object KotlinConverter {
     }
 
 
-    internal fun convert(entry: KtStringTemplateEntry, parent: UElement?): UExpression = when (entry) {
-        is KtStringTemplateEntryWithExpression -> KotlinConverter.convertOrEmpty(entry.expression, parent)
-        is KtEscapeStringTemplateEntry -> KotlinStringULiteralExpression(entry, parent, entry.unescapedValue)
-        else -> {
-            KotlinStringULiteralExpression(entry, parent)
+    internal fun convertEntry(entry: KtStringTemplateEntry,
+                              parentCallback: (() -> UElement?)?,
+                              requiredType: Class<out UElement>? = null): UExpression? {
+        return with(requiredType) {
+            if (entry is KtStringTemplateEntryWithExpression) {
+                expr<UExpression> {
+                    val parent = if (parentCallback == null) null else (parentCallback() ?: return null)
+                    KotlinConverter.convertOrEmpty(entry.expression, parent)
+                }
+            }
+            else {
+                expr<ULiteralExpression> {
+                    val parent = if (parentCallback == null) null else (parentCallback() ?: return null)
+                    if (entry is KtEscapeStringTemplateEntry)
+                        KotlinStringULiteralExpression(entry, parent, entry.unescapedValue)
+                    else
+                        KotlinStringULiteralExpression(entry, parent)
+                }
+            }
         }
     }
 
-
     internal fun convertExpression(expression: KtExpression,
                                    parentCallback: (() -> UElement?)?,
                                    requiredType: Class<out UElement>? = null): UExpression? {
@@ -272,14 +285,17 @@ internal object KotlinConverter {
         return with (requiredType) { when (expression) {
             is KtVariableDeclaration -> expr<UDeclarationsExpression>(build(::convertVariablesDeclaration))
 
-            is KtStringTemplateExpression -> expr<ULiteralExpression> {
-                val parent = if (parentCallback == null) null else (parentCallback() ?: return null)
-                if (expression.entries.isEmpty())
-                    KotlinStringULiteralExpression(expression, parent, "")
+            is KtStringTemplateExpression -> {
+                if (expression.entries.isEmpty()) {
+                    val parent = if (parentCallback == null) null else (parentCallback() ?: return null)
+                    expr<ULiteralExpression> { KotlinStringULiteralExpression(expression, parent, "") }
+                }
                 else if (expression.entries.size == 1)
-                    convert(expression.entries[0], parent)
-                else
-                    KotlinStringTemplateUPolyadicExpression(expression, parent)
+                    convertEntry(expression.entries[0], parentCallback, requiredType)
+                else {
+                    val parent = if (parentCallback == null) null else (parentCallback() ?: return null)
+                    expr<UExpression> { KotlinStringTemplateUPolyadicExpression(expression, parent) }
+                }
             }
             is KtDestructuringDeclaration -> expr<UDeclarationsExpression> {
                 val parent = if (parentCallback == null) null else (parentCallback() ?: return null)

plugins/uast-kotlin/src/org/jetbrains/uast/kotlin/expressions/KotlinStringTemplateUPolyadicExpression.kt

@@ -29,6 +29,6 @@ class KotlinStringTemplateUPolyadicExpression(
         UPolyadicExpression,
         KotlinUElementWithType,
         KotlinEvaluatableUElement {
-    override val operands: List<UExpression> by lz { psi.entries.map { KotlinConverter.convert(it, this) } }
+    override val operands: List<UExpression> by lz { psi.entries.map { KotlinConverter.convertEntry(it, { this })!! } }
     override val operator = UastBinaryOperator.PLUS
 }

plugins/uast-kotlin/testData/StringTemplateWithVar.kt

@@ -0,0 +1,2 @@
+val bar = "bar"
+val f = "foo$bar"

plugins/uast-kotlin/tests/KotlinUastApiTest.kt

@@ -1,11 +1,10 @@
 package org.jetbrains.uast.test.kotlin
 
 import org.jetbrains.kotlin.psi.KtLiteralStringTemplateEntry
-import org.jetbrains.uast.UAnnotation
-import org.jetbrains.uast.UFile
-import org.jetbrains.uast.ULiteralExpression
+import org.jetbrains.kotlin.psi.KtStringTemplateExpression
+import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
+import org.jetbrains.uast.*
 import org.jetbrains.uast.test.env.findElementByText
-import org.jetbrains.uast.toUElement
 import org.junit.Assert
 import org.junit.Test
 
@@ -32,4 +31,13 @@ class KotlinUastApiTest : AbstractKotlinUastTest() {
 
         }
     }
+
+    @Test fun testConvertStringTemplateWithExpectedType() {
+        doTest("StringTemplateWithVar") { _, file ->
+            val index = file.psi.text.indexOf("foo")
+            val stringTemplate = file.psi.findElementAt(index)!!.getParentOfType<KtStringTemplateExpression>(false)
+            val uLiteral = stringTemplate.toUElementOfType<ULiteralExpression>()
+            assertNull(uLiteral)
+        }
+    }
 }