[clang] [C] Disallow declarations where a statement is required (PR #92908)

[Shafik Yaghmour via cfe-commits]

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@@ -467,15 +467,18 @@ class Parser : public CodeCompletionHandler {
 
   /// Flags describing a context in which we're parsing a statement.
   enum class ParsedStmtContext {
+    /// This context permits declarations in language modes where declarations
+    /// are not statements.
+    AllowDeclarationsInC = 0x1,
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shafik wrote:

This feels a little mysterious, I only see that we check it but it is not obvious how it gets set. 

https://github.com/llvm/llvm-project/pull/92908