build_m_component_ref checks if either datum/component it got are erroneous but they can be turned into the error_mark_node by mark_use as in this case: datum is "a" before the call to mark_lvalue_use, but that emits an error and returns the error_mark_node, which then crashes.
We can just move the checks after calling mark_[lr]value_use; those just return when they get the error_mark_node. But I tweaked mark_use to also handle the case when the type is erroneous. Bootstrapped/regtested on x86_64-linux, ok for trunk? 2019-09-23 Marek Polacek <pola...@redhat.com> PR c++/91845 - ICE with invalid pointer-to-member. * expr.c (mark_use): Use error_operand_p. * typeck2.c (build_m_component_ref): Check error_operand_p after calling mark_[lr]value_use. * g++.dg/cpp1y/pr91845.C: New test. diff --git gcc/cp/expr.c gcc/cp/expr.c index 212a7f93c5a..d488912d5db 100644 --- gcc/cp/expr.c +++ gcc/cp/expr.c @@ -96,7 +96,7 @@ mark_use (tree expr, bool rvalue_p, bool read_p, { #define RECUR(t) mark_use ((t), rvalue_p, read_p, loc, reject_builtin) - if (expr == NULL_TREE || expr == error_mark_node) + if (expr == NULL_TREE || error_operand_p (expr)) return expr; if (reject_builtin && reject_gcc_builtin (expr, loc)) diff --git gcc/cp/typeck2.c gcc/cp/typeck2.c index d5098fa24bb..58fa54f40af 100644 --- gcc/cp/typeck2.c +++ gcc/cp/typeck2.c @@ -2068,12 +2068,12 @@ build_m_component_ref (tree datum, tree component, tsubst_flags_t complain) tree binfo; tree ctype; - if (error_operand_p (datum) || error_operand_p (component)) - return error_mark_node; - datum = mark_lvalue_use (datum); component = mark_rvalue_use (component); + if (error_operand_p (datum) || error_operand_p (component)) + return error_mark_node; + ptrmem_type = TREE_TYPE (component); if (!TYPE_PTRMEM_P (ptrmem_type)) { diff --git gcc/testsuite/g++.dg/cpp1y/pr91845.C gcc/testsuite/g++.dg/cpp1y/pr91845.C new file mode 100644 index 00000000000..cb80dd7a8a7 --- /dev/null +++ gcc/testsuite/g++.dg/cpp1y/pr91845.C @@ -0,0 +1,14 @@ +// PR c++/91845 - ICE with invalid pointer-to-member. +// { dg-do compile { target c++14 } } + +void non_const_mem_ptr() { + struct A { + }; + constexpr A a = {1, 2}; // { dg-error "too many initializers" } + struct B { + int A::*p; + constexpr int g() const { + return a.*p; // { dg-error "use of local variable" } + }; + }; +}