Dispose range markers in UI thread to prevent race condition at getting range (KT-28870)

#KT-28870 Fixed

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

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.idea.conversion.copy
 
+import com.intellij.openapi.diagnostic.Logger
 import com.intellij.openapi.editor.RangeMarker
 import com.intellij.openapi.util.TextRange
 import com.intellij.psi.PsiElement
@@ -32,4 +33,16 @@ val PsiElement.range: TextRange
     get() = textRange!!
 
 val RangeMarker.range: TextRange?
-    get() = if (isValid) TextRange(startOffset, endOffset) else null
+    get() = if (isValid) {
+        val start = startOffset
+        val end = endOffset
+        if (start in 0..end) {
+            TextRange(start, end)
+        } else {
+            // Probably a race condition had happened
+            LOG.error("Invalid range [$start, $end] for range marker (valid = $isValid)")
+            null
+        }
+    } else null
+
+private val LOG = Logger.getInstance("RangeUtils")

idea/src/org/jetbrains/kotlin/idea/parameterInfo/custom/KotlinCodeHintsModel.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.idea.parameterInfo.custom
 
+import com.intellij.openapi.application.ApplicationManager
 import com.intellij.openapi.editor.Document
 import com.intellij.openapi.editor.Editor
 import com.intellij.openapi.editor.EditorFactory
@@ -66,8 +67,11 @@ class KotlinCodeHintsModel(val project: Project) : EditorFactoryListenerWrapper
         }
 
         fun dispose() {
-            for (marker in lineEndMarkers.keys()) {
+            val keys = lineEndMarkers.keys()
-                marker.dispose()
+            ApplicationManager.getApplication().invokeLater {
+                for (marker in keys) {
+                    marker.dispose()
+                }
             }
         }
     }