[PATCH] D140828: [C++] Implement "Deducing this" (P0847R7)

[Corentin Jabot via Phabricator via cfe-commits]

cor3ntin marked an inline comment as done.
cor3ntin added inline comments.


================
Comment at: clang/lib/CodeGen/CGExpr.cpp:4283
+  if (HasExplicitObjectParameter) {
+    const VarDecl *D = cast<CXXMethodDecl>(CurCodeDecl)->getParamDecl(0);
+    auto It = LocalDeclMap.find(D);
----------------
aaron.ballman wrote:
> Above we did `dyn_cast_if_present<CXXMethodDecl>(CurCodeDecl)` and here we're doing a straight-up `cast<>`. Which is incorrect?
neither, once `HasExplicitObjectParameter` is true we know it's a CXXMethodDecl


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Comment at: clang/test/SemaCXX/cxx2b-deducing-this.cpp:42
+    int f(this B&, int); // expected-warning {{hides overloaded virtual function}}
+    int f(this B&);  // expected-error {{an explicit object parameter cannot appear in a virtual function}}
+    int g(this B&); // expected-warning {{hides overloaded virtual function}}
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aaron.ballman wrote:
> According to the paper, this is accepted but `B::f()` does not override `A::f()`.
> 
> https://eel.is/c++draft/dcl.fct#6.sentence-3
> 
> `B::f()` is not declared as virtual, only `A::f()` is.
> 
> When this gets corrected, please add some codegen tests to demonstrate that a call to `f()` does not dispatch to `B::f()` unless the static type of the object is `B`.
This is this is https://cplusplus.github.io/CWG/issues/2553.html, I will leave a comment to clarify


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  https://reviews.llvm.org/D140828/new/

https://reviews.llvm.org/D140828