Here enclosing_instantiation_of was failing to find a match because otctx is
struct S<T> and current_function_decl is S<int>::S(), so the latter has more
function contexts, and we end up trying to compare S() to NULL_TREE.
After spending a bit of time working on establishing the correspondence in
this case (class <=> constructor), it occurred to me that we could just use
DECL_SOURCE_LOCATION, which is unique for lambdas, since they cannot be
redeclared. Since we're so close to release, for now I'm only doing this
for the case that was failing before.
gcc/cp/ChangeLog:
PR c++/95870
* pt.c (enclosing_instantiation_of): Compare DECL_SOURCE_LOCATION if
there is no enclosing non-lambda function.
gcc/testsuite/ChangeLog:
PR c++/95870
* g++.dg/cpp0x/lambda/lambda-nsdmi10.C: New test.
|| instantiated_lambda_fn_p (tctx));
tctx = decl_function_context (tctx))
++lambda_count;
+
+ if (!tctx)
+ {
+ /* Match using DECL_SOURCE_LOCATION, which is unique for all lambdas.
+
+ For GCC 11 the above condition limits this to the previously failing
+ case where all enclosing functions are lambdas (95870). FIXME. */
+ for (tree ofn = fn; ofn; ofn = decl_function_context (ofn))
+ if (DECL_SOURCE_LOCATION (ofn) == DECL_SOURCE_LOCATION (otctx))
+ return ofn;
+ gcc_unreachable ();
+ }
+
for (; fn; fn = decl_function_context (fn))
{
tree ofn = fn;
--- /dev/null
+// PR c++/95870
+// { dg-do compile { target c++11 } }
+
+template <typename> struct S {
+ S();
+ int b = []() -> int { enum E {}; return 1; }();
+};
+struct C : S<int> {
+ C();
+};
+template <typename T> S<T>::S() = default;
+C::C() {}