https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97372
--- Comment #4 from marian <public at enkore dot de> --- Running gcc under valgrind with the original testcase produces some interesting output. These binaries of course barely have any symbols at all, but it might at least provide a hint: ==882380== Invalid read of size 2 ==882380== at 0x75DCA1: ??? (in /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/cc1plus) ==882380== by 0x2: ??? ==882380== by 0x771307: ??? (in /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/cc1plus) ==882380== by 0x76F4CD: ??? (in /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/cc1plus) ==882380== by 0x76D86E: ??? (in /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/cc1plus) ==882380== by 0x76CFBD: ??? (in /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/cc1plus) ==882380== by 0x76CFBD: ??? (in /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/cc1plus) ==882380== by 0x77206F: tsubst_lambda_expr(tree_node*, tree_node*, int, tree_node*) (in /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/cc1plus) ==882380== by 0x7748C3: ??? (in /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/cc1plus) ==882380== by 0x773684: ??? (in /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/cc1plus) ==882380== by 0x774CA4: ??? (in /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/cc1plus) ==882380== by 0x6E8EE9: get_nsdmi(tree_node*, bool, int) (in /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/cc1plus) ==882380== Address 0x0 is not stack'd, malloc'd or (recently) free'd
