Refactoring: rewrite without local any values

idea/idea-jvm/src/org/jetbrains/kotlin/idea/injection/InterpolatedStringInjectorProcessor.kt

@@ -18,7 +18,6 @@ package org.jetbrains.kotlin.idea.injection
 
 import com.intellij.openapi.util.TextRange
 import com.intellij.openapi.util.Trinity
-import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiLanguageInjectionHost
 import org.intellij.plugins.intelliLang.inject.InjectedLanguage
 import org.intellij.plugins.intelliLang.inject.InjectorUtils
@@ -48,59 +47,66 @@ fun splitLiteralToInjectionParts(injection: BaseInjection, literal: KtStringTemp
         result.add(Trinity.create(literal, injectedLanguage, range))
     }
 
+    fun suffix(i: Int) = if (i == len - 1) injection.suffix else ""
+
     var unparsable = false
 
     var prefix = injection.prefix
-    val lastChild = children.lastOrNull()
 
     var i = 0
     while (i < len) {
         val child = children[i]
         val partOffsetInParent = child.startOffsetInParent
 
-        @Suppress("IMPLICIT_CAST_TO_ANY")
-        val part = when (child) {
-            is KtLiteralStringTemplateEntry, is KtEscapeStringTemplateEntry -> {
-                val partSize = children.subList(i, len).asSequence()
-                    .takeWhile { it is KtLiteralStringTemplateEntry || it is KtEscapeStringTemplateEntry }
-                    .count()
-                i += partSize - 1
-                children[i]
+        if (child is KtSimpleNameStringTemplateEntry || child is KtBlockStringTemplateEntry) {
+            if (!prefix.isEmpty() || i == 0) {
+                // Store part with prefix before replacing it
+                addInjectionRange(TextRange.from(partOffsetInParent, 0), prefix, suffix(i))
             }
-            is KtSimpleNameStringTemplateEntry ->
-                tryEvaluateConstant(child.expression) ?: run {
-                    unparsable = true
-                    child.expression?.text ?: NO_VALUE_NAME
+
+            prefix = when (child) {
+                is KtSimpleNameStringTemplateEntry -> {
+                    tryEvaluateConstant(child.expression) ?: run {
+                        unparsable = true
+                        child.expression?.text ?: NO_VALUE_NAME
+                    }
                 }
-            is KtBlockStringTemplateEntry ->
-                tryEvaluateConstant(child.expression) ?: run {
-                    unparsable = true
-                    NO_VALUE_NAME
+                is KtBlockStringTemplateEntry -> {
+                    tryEvaluateConstant(child.expression) ?: run {
+                        unparsable = true
+                        NO_VALUE_NAME
+                    }
                 }
-            else -> {
+                else -> {
+                    error("Child type should be KtSimpleNameStringTemplateEntry or KtBlockStringTemplateEntry")
+                }
+            }
+
+            if (i == len - 1 && !prefix.isEmpty()) {
+                // There won't be more elements, so create part with prefix right away
+                addInjectionRange(TextRange.from(partOffsetInParent + child.textLength, 0), prefix, suffix(i))
+            }
+        } else {
+            if (child is KtLiteralStringTemplateEntry || child is KtEscapeStringTemplateEntry) {
+                // Merge all consecutive string literals into one part
+                i += children.countFromWhile(i + 1) { it is KtLiteralStringTemplateEntry || it is KtEscapeStringTemplateEntry }
+            } else {
                 unparsable = true
-                child
             }
+
+            val lastInPart = children[i]
+            addInjectionRange(
+                TextRange.create(partOffsetInParent, lastInPart.startOffsetInParent + lastInPart.textLength),
+                prefix,
+                suffix(i)
+            )
+
+            prefix = ""
         }
 
-        val suffix = if (i == len - 1) injection.suffix else ""
-
-        if (part is PsiElement) {
-            addInjectionRange(TextRange.create(partOffsetInParent, part.startOffsetInParent + part.textLength), prefix, suffix)
-        }
-        else if (!prefix.isEmpty() || i == 0) {
-            addInjectionRange(TextRange.from(partOffsetInParent, 0), prefix, suffix)
-        }
-
-        prefix = part as? String ?: ""
         i++
     }
 
-    if (lastChild != null && !prefix.isEmpty()) {
-        // Last element was interpolated part, need to add a range after it
-        addInjectionRange(TextRange.from(lastChild.startOffsetInParent + lastChild.textLength, 0), prefix, injection.suffix)
-    }
-
     return InjectionSplitResult(unparsable, result)
 }
 
@@ -112,4 +118,16 @@ private fun tryEvaluateConstant(ktExpression: KtExpression?) =
             ?.safeAs<String>()
     }
 
-private val NO_VALUE_NAME = "missingValue"
+private const val NO_VALUE_NAME = "missingValue"
+
+private inline fun <T : Any> List<T>.countFromWhile(from: Int, predicate: (T) -> Boolean): Int {
+    var i = from
+    while (i < size) {
+        if (!predicate(get(i))) {
+            break
+        }
+        i++
+    }
+
+    return i - from
+}