Minor

idea/src/org/jetbrains/jet/plugin/completion/CompletionSession.kt

@@ -194,7 +194,7 @@ abstract class CompletionSessionBase(protected val configuration: CompletionSess
     }
 
     protected fun shouldRunExtensionsCompletion(): Boolean
-            = configuration.completeNonImportedDeclarations || prefixMatcher.getPrefix().length() >= 3
+            = configuration.completeNonImportedDeclarations || prefix.length() >= 3
 
     protected fun getKotlinTopLevelCallables(): Collection<DeclarationDescriptor>
             = indicesHelper.getTopLevelCallables({ prefixMatcher.prefixMatches(it) }, reference!!.expression)

idea/src/org/jetbrains/jet/plugin/completion/CompletionUtils.kt

@@ -210,10 +210,7 @@ fun InsertionContext.isAfterDot(): Boolean {
 fun shouldCompleteThisItems(prefixMatcher: PrefixMatcher): Boolean {
     val prefix = prefixMatcher.getPrefix()
     val s = "this@"
-    return if (prefix.length() > s.length())
-        prefix.startsWith(s)
-    else
-        s.startsWith(prefix)
+    return prefix.startsWith(s) || s.startsWith(prefix)
 }
 
 data class ThisItemInfo(val factory: () -> LookupElement, val type: FuzzyType)

idea/src/org/jetbrains/jet/plugin/editor/KotlinTypedHandler.java

@@ -160,6 +160,7 @@ public class KotlinTypedHandler extends TypedHandlerDelegate {
     }
 
     private static boolean endsWith(CharSequence chars, int offset, String text) {
+        if (offset < text.length()) return false;
         return chars.subSequence(offset - text.length(), offset).toString().equals(text);
     }