Correctly handle editor selection in "Show expression type"

To avoid showing a large list, the previous logic returned only the
element directly at caret and other elements with the same start
offset. When selection is present, the platform logic looks only at
elements which have a larger range than the selection, so our elements
could be completely filtered out. Now we look at the selection
ourselves and adjust the returned elements accordingly.

 #KT-16423 Fixed

idea/src/org/jetbrains/kotlin/idea/codeInsight/KotlinExpressionTypeProvider.kt

@@ -17,6 +17,10 @@
 package org.jetbrains.kotlin.idea.codeInsight
 
 import com.intellij.lang.ExpressionTypeProvider
+import com.intellij.openapi.editor.ex.util.EditorUtil
+import com.intellij.openapi.fileEditor.FileEditorManager
+import com.intellij.openapi.fileEditor.TextEditor
+import com.intellij.openapi.util.TextRange
 import com.intellij.psi.PsiElement
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.descriptors.ClassifierDescriptor
@@ -50,7 +54,14 @@ class KotlinExpressionTypeProvider : ExpressionTypeProvider<KtExpression>() {
 
     override fun getExpressionsAt(elementAt: PsiElement): List<KtExpression> {
         val candidates = elementAt.parentsWithSelf.filterIsInstance<KtExpression>().filter { it.shouldShowType() }.toList()
-        return candidates.takeWhile { it.textRange.startOffset == candidates.first().textRange.startOffset }
+        val fileEditor = elementAt.containingFile?.virtualFile?.let { FileEditorManager.getInstance(elementAt.project).getSelectedEditor(it) }
+        val selectionTextRange = if (fileEditor is TextEditor) {
+            EditorUtil.getSelectionInAnyMode(fileEditor.editor)
+        } else {
+            TextRange.EMPTY_RANGE
+        }
+        val anchor = candidates.firstOrNull { selectionTextRange.isEmpty || it.textRange.contains(selectionTextRange) } ?: return emptyList()
+        return candidates.filter { it.textRange.startOffset == anchor.textRange.startOffset }
     }
 
     private fun KtExpression.shouldShowType() = when (this) {