https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83692
Bug ID: 83692
Summary: Rejects valid constexpr with unrelated code fixing
problem
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: david at doublewise dot net
Target Milestone: ---
The following program fails to compile
struct integer {
constexpr int value() const {
return m_value;
}
int m_value;
};
struct outer {
integer m_x{0};
constexpr outer() {
if (m_x.value() != 0) throw 0;
m_x.m_value = integer{1}.value();
if (m_x.value() != 1) throw 0;
}
};
constexpr outer o{};
Giving the error message:
17 : <source>:17:19: in 'constexpr' expansion of 'outer()'
13 : <source>:13:37: error: expression '<throw-expression>' is not a constant
expression
if (m_x.value() != 1) throw 0;
^
Compiler returned: 1
Seemingly insignificant changes in the code lead to the error disappearing: for
instance, removing the first if statement (which is not rejected as invalid)
causes the second if statement to be accepted.
