[clang] [clang][Sema] Guard diagnose_if value-dependent conditions (PR #197647)

[Erich Keane via cfe-commits]

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@@ -7801,8 +7801,12 @@ bool Sema::diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function,
         // It's sane to use the same Args for any redecl of this function, since
         // EvaluateWithSubstitution only cares about the position of each
         // argument in the arg list, not the ParmVarDecl* it maps to.
-        if (!DIA->getCond()->EvaluateWithSubstitution(
-                Result, Context, cast<FunctionDecl>(DIA->getParent()), Args, ThisArg))
+        // FIXME: This doesn't consider value-dependent cases, because doing so
+        // is very difficult. Ideally, we should handle them more gracefully.
+        if (DIA->getCond()->isValueDependent() ||
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erichkeane wrote:

What do you mean by `error dependency bit`?  Do you mean the `RecoveryExpr` 'has error` thing?  If so, I don't think that really carries any problems other than perhaps some awkward diagnostics later.  We could perhaps have `hasError` checked here and ALSO return `false`, which would be completely sensible, though the result is 'we choose one of the behaviors here on error'.


https://github.com/llvm/llvm-project/pull/197647