Hi! While cp_parser_lambda_body which is the other finish_lambda_function caller next to tsubst_lambda_expr temporarily increments function_depth around that call (if not nested) to avoid GC during expand_or_defer_fn from finish_lambda_function, tsubst_lambda_expr doesn't, and on the lambda-ice14.C we can see the GC in action in that case.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2018-02-19 Jakub Jelinek <ja...@redhat.com> PR c++/84455 * pt.c (tsubst_lambda_expr): If not nested, increment temporarily function_depth to avoid GC during finish_lambda_function. * g++.dg/cpp0x/lambda/lambda-ice26.C: New test. --- gcc/cp/pt.c.jj 2018-02-16 23:37:29.312364263 +0100 +++ gcc/cp/pt.c 2018-02-19 10:48:00.328184302 +0100 @@ -17070,6 +17070,10 @@ tsubst_lambda_expr (tree t, tree args, t bool nested = cfun; if (nested) push_function_context (); + else + /* Still increment function_depth so that we don't GC in the + middle of an expression. */ + ++function_depth; local_specialization_stack s (lss_copy); @@ -17084,6 +17088,8 @@ tsubst_lambda_expr (tree t, tree args, t if (nested) pop_function_context (); + else + --function_depth; /* The capture list was built up in reverse order; fix that now. */ LAMBDA_EXPR_CAPTURE_LIST (r) --- gcc/testsuite/g++.dg/cpp0x/lambda/lambda-ice26.C.jj 2018-02-19 10:51:24.838188732 +0100 +++ gcc/testsuite/g++.dg/cpp0x/lambda/lambda-ice26.C 2018-02-19 10:51:19.690188624 +0100 @@ -0,0 +1,5 @@ +// PR c++/84455 +// { dg-do compile { target c++11 } } +// { dg-options "--param ggc-min-heapsize=0" } + +#include "lambda-ice14.C" Jakub