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Re: [C++ PATCH] PR c++/79133
On 7 July 2018 at 21:55, Ville Voutilainen <ville.voutilainen@gmail.com> wrote:
> On 7 July 2018 at 21:12, Paolo Carlini <paolo.carlini@oracle.com> wrote:
>> Should we really print the same name twice? Looks like we don't have
>> available (yet) a location for cap - that would likely enable fancy things -
>> but in that case too I don't think the user would find that interesting
>> seeing the same name twice. Also, we are using %E, thus we are pretty
>> printing expressions - which in general we don't want to do - I see that in
>> the case of cap it gives pretty obfuscated results for the last two tests
>> (what the heck is __lambda3?!?). So, all in all, maybe print the name once,
>> as parms, or something like that, for the time being? Or try to avoid %E
>> altogether?
>
> What should I print instead of %E?
%qD instead of %qE, presumably. That seems to do the same thing in the
new patch, but I can sure change it.
Attached.
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 3aafb0f..b883054 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -2640,6 +2640,7 @@ check_local_shadow (tree decl)
|| TREE_CODE (decl) == TYPE_DECL)))
&& DECL_FUNCTION_SCOPE_P (old)
&& (!DECL_ARTIFICIAL (decl)
+ || is_capture_proxy (decl)
|| DECL_IMPLICIT_TYPEDEF_P (decl)
|| (VAR_P (decl) && DECL_ANON_UNION_VAR_P (decl))))
{
@@ -2648,7 +2649,8 @@ check_local_shadow (tree decl)
/* Don't complain if it's from an enclosing function. */
if (DECL_CONTEXT (old) == current_function_decl
&& TREE_CODE (decl) != PARM_DECL
- && TREE_CODE (old) == PARM_DECL)
+ && TREE_CODE (old) == PARM_DECL
+ && !is_capture_proxy (decl))
{
/* Go to where the parms should be and see if we find
them there. */
@@ -2665,6 +2667,20 @@ check_local_shadow (tree decl)
return;
}
}
+ /* DR 2211: check that captures and parameters
+ do not have the same name. */
+ else if (current_lambda_expr ()
+ && DECL_CONTEXT (old) == lambda_function (current_lambda_expr ())
+ && TREE_CODE (old) == PARM_DECL
+ && is_capture_proxy (decl))
+ {
+ if (DECL_NAME (decl) != this_identifier)
+ error_at (DECL_SOURCE_LOCATION (old),
+ "capture %qD and lambda parameter %qD "
+ "have the same name",
+ decl, old);
+ return;
+ }
/* The local structure or class can't use parameters of
the containing function anyway. */
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-shadow3.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-shadow3.C
new file mode 100644
index 0000000..b006470
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-shadow3.C
@@ -0,0 +1,12 @@
+// { dg-do compile { target c++14 } }
+
+int main() {
+ int x = 42;
+ auto lambda = [x](int x) {}; // { dg-error "have the same name" }
+ auto lambda2 = [x=x](int x) {}; // { dg-error "have the same name" }
+ auto lambda3 = [x](auto... x) {}; // { dg-error "have the same name" }
+ auto lambda4 = [](auto... x) {
+ auto lambda5 = [x...](auto... x) {}; // { dg-error "have the same name" }
+ auto lambda6 = [x...](int x) {}; // { dg-error "have the same name" }
+ };
+}