[PATCH] D85613: [clang] Look through bindings when checking whether a default argument references a local entity.

[Richard Smith - zygoloid via Phabricator via cfe-commits]

rsmith added inline comments.


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Comment at: clang/lib/Sema/SemaDeclCXX.cpp:101-105
+    if (const VarDecl *HoldingVar = Binding->getHoldingVar()) {
+      // C++20 [dcl.struct.bind]p4:
+      //   Each vi is the name [...] that refers to the object bound to ri [...]
+      Decl = HoldingVar;
+    } else {
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Is there a reason to separate these two cases? (Could we just use the decomposed decl unconditionally?) Generally treating tuple-like decompositions differently from other kinds seems error-prone.


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Comment at: clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p7.cpp:51
+  extern void h8a(int = sizeof(z)); // ok
+  extern void h8b(int = w);         // expected-error {{default argument references local variable 'w'}}
 
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The diagnostic in this case is inconsistent with the non-tuple-like cases. I think this diagnostic is better; we should use the original `Decl` when producing the diagnostic, not the decomposed variable.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D85613/new/

https://reviews.llvm.org/D85613