[llvm] [YAMLParser] Improve plain scalar spec compliance (PR #68946)

[Scott Linder via llvm-commits]

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@@ -1848,13 +1869,15 @@ bool Scanner::fetchMoreTokens() {
   if (*Current == ',')
     return scanFlowEntry();
 
-  if (*Current == '-' && isBlankOrBreak(Current + 1))
+  if (*Current == '-' && (isBlankOrBreak(Current + 1) || Current + 1 == End))
     return scanBlockEntry();
 
-  if (*Current == '?' && (FlowLevel || isBlankOrBreak(Current + 1)))
+  if (*Current == '?' && (Current + 1 == End || isBlankOrBreak(Current + 1)))
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slinder1 wrote:

Ditto here, but also a separate case for the expanded complex-key outside of flow case

https://github.com/llvm/llvm-project/pull/68946