[CodeCompletion] Fix incorrect upper bound for assertion

This assertion was bogus if there were fewer results than N.

Author: benlangmuir

test/SourceKit/CodeComplete/complete_sort_order.swift

@@ -118,6 +118,15 @@ func test3(x: Int) {
 // EXPR_TOP_1: z
 // EXPR_TOP_1: zzz
 
+// Test where there are fewer results than 'top'.
+// RUN: %complete-test -top=1000 -tok=FEW_1 %s | FileCheck %s -check-prefix=FEW_1
+func test3b() -> Int {
+  return #^FEW_1^#
+}
+// FEW_1: test3b()
+// FEW_1: Int
+// FEW_1: 0
+
 // Top 3
 // RUN: %complete-test -top=3 -tok=EXPR_2 %s | FileCheck %s -check-prefix=EXPR_TOP_3
 func test4(x: Int) {

tools/SourceKit/lib/SwiftLang/CodeCompletionOrganizer.cpp

@@ -924,7 +924,7 @@ static void sortTopN(const Options &options, Group *group,
     if (!beginNewIndex)
       return;
 
-    assert(endNewIndex > beginNewIndex && endNewIndex < contents.size());
+    assert(endNewIndex > beginNewIndex && endNewIndex <= contents.size());
 
     // Temporarily copy the first result to temporary storage.
     SmallVector<Item *, 16> firstResults;
@@ -938,6 +938,7 @@ static void sortTopN(const Options &options, Group *group,
       contents[ci] = std::unique_ptr<Item>(firstResults[i]);
     }
     unsigned topN = endNewIndex - beginNewIndex;
+    assert(topN <= options.showTopNonLiteralResults);
     for (unsigned ci = topN, i = 0; i < beginNewIndex; ++i, ++ci) {
       assert(ci < contents.size() && !contents[ci]);
       contents[ci] = std::unique_ptr<Item>(firstResults[i]);