[clang] [clang] Remove the EnableLifetimeWarnings flag in lifetime analysis. (PR #105884)

[Haojian Wu via cfe-commits]

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@@ -408,7 +405,8 @@ static void visitFunctionCallArguments(IndirectLocalPath &Path, Expr *Call,
     // Once we initialized a value with a reference, it can no longer dangle.
     if (!Value) {
       for (const IndirectLocalPathEntry &PE : llvm::reverse(Path)) {
-        if (PE.Kind == IndirectLocalPathEntry::GslReferenceInit)
+        if (PE.Kind == IndirectLocalPathEntry::GslReferenceInit ||
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hokein wrote:

This code isn't used elsewhere, so I think it's fine to leave it as is (and I'm not sure it's a good idea to expose it as a function).

I think this section could benefit from better documentation. Essentially, it bails out cases where we construct a GSL pointer from a reference, and before this change, the path could only contain GSL-specific IndirectLocalPathEntry. With this change, we should also consider the LifetimeBoundCall.

There’s also some refactoring and enhancement in this part of the code in #104556, and I’ll add more documentation there.

https://github.com/llvm/llvm-project/pull/105884