Sema: Fix crash on invalid code in diagnoseDictionaryLiteralDuplicateKeyEntries()

Author: slavapestov

lib/Sema/MiscDiagnostics.cpp

@@ -6268,9 +6268,9 @@ diagnoseDictionaryLiteralDuplicateKeyEntries(const Expr *E,
         note.fixItRemove(duplicated.first->getSourceRange());
         if (duplicatedEltIdx < commanLocs.size()) {
           note.fixItRemove(commanLocs[duplicatedEltIdx]);
-        } else {
+        } else if (!commanLocs.empty()) {
           // For the last element remove the previous comma.
-          note.fixItRemove(commanLocs[duplicatedEltIdx - 1]);
+          note.fixItRemove(commanLocs[commanLocs.size() - 1]);
         }
       };
 

validation-test/compiler_crashers_2/93eaba9fd0e76cdf.swift renamed to validation-test/compiler_crashers_2_fixed/93eaba9fd0e76cdf.swift

@@ -1,3 +1,3 @@
 // {"signature":"diagnoseDictionaryLiteralDuplicateKeyEntries(swift::Expr const*, swift::DeclContext const*)::DiagnoseWalker::walkToExprPre(swift::Expr*)"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 [ 1.01: "" 1.01: ""