Fix <rdar://problem/6454568>: BugReporter should correctly handle switch statements with no default case.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@61270 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/BugReporter.cpp b/lib/Analysis/BugReporter.cpp
index 8274ce7..e6840c3 100644
--- a/lib/Analysis/BugReporter.cpp
+++ b/lib/Analysis/BugReporter.cpp
@@ -549,12 +549,14 @@
           if (Stmt* S = Dst->getLabel())
             switch (S->getStmtClass()) {
                 
-            default:
-              assert(false && "Not a valid switch label.");
-              continue;
+            default: {
+              os << "No cases match in the switch statement. "
+                    "Control jumps to line "
+                 << SMgr.getLogicalLineNumber(S->getLocStart()) << ".\n";
+                break;
+            }
                 
-            case Stmt::DefaultStmtClass: {              
-              
+            case Stmt::DefaultStmtClass: {                            
               os << "Control jumps to the 'default' case at line "
                  << SMgr.getLogicalLineNumber(S->getLocStart()) << ".\n";