In a template we were happily embedding error_mark_node in a MODOP_EXPR,
leading to confusion later.
Tested x86_64-pc-linux-gnu, applying to trunk.
gcc/cp/ChangeLog
2020-05-21 Jason Merrill
* typeck.c (build_x_modify_expr): Handle error_mark_node arguments.
---
gcc/cp/typeck.c
If a parameter is erroneous, we currently drop it, leading to "too many
arguments" errors later. Treating the function as (...) avoids those
errors.
Tested x86_64-pc-linux-gnu, applying to trunk.
gcc/cp/ChangeLog
2020-05-21 Jason Merrill
* decl.c (grokparms): Return NULL_TREE if any
