[PATCH] D125622: [clang-tidy] Reject invalid enum initializers in C files

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added inline comments.


================
Comment at: clang-tools-extra/test/clang-tidy/checkers/modernize-macro-to-enum.c:9
+
+// C forbids comma operator in initializing expressions.
+#define BAD_OP 1, 2
----------------
LegalizeAdulthood wrote:
> aaron.ballman wrote:
> > It's also forbidden in C++.
> C++ just talks about a constant expression and doesn't explicitly disallow `operator,` in such expressions that I could find.  Can you point me to where it is disallowed?
> 
> If it is disallowed universally, then I don't see why you asked me to parse it `:)`
> C++ just talks about a constant expression and doesn't explicitly disallow operator, in such expressions that I could find. Can you point me to where it is disallowed?

It falls out from the grammar:

http://eel.is/c++draft/enum#nt:enumerator-definition
http://eel.is/c++draft/expr.const#nt:constant-expression
http://eel.is/c++draft/expr.cond#nt:conditional-expression

> If it is disallowed universally, then I don't see why you asked me to parse it :)

It can show up in paren expressions and the interface is generally about integer literal expressions.


Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D125622/new/

https://reviews.llvm.org/D125622