https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65293
Bug ID: 65293
Summary: improve error message on static_casting incomplete
types.
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: chengniansun at gmail dot com
It took me a while to figure out that the cause of the error is the incomplete
definition of destination type. I wonder whether it is possible to improve the
error message by mentioning "incomplete", similar to what Clang does. I believe
doing this will provide more information to developers to fix this type of
errors.
$: cat t.cc
class A;
class B;
void f(const B &b) {
const A &a = static_cast<const A&>(b);
}
$:
$:
$: ~/tools/gcc-install/bin/g++ -c t.cc
t.cc: In function ‘void f(const B&)’:
t.cc:5:39: error: invalid static_cast from type ‘const B’ to type ‘const A&’
const A &a = static_cast<const A&>(b);
^
$:
$: clang++ -c t.cc
t.cc:5:16: error: no viable conversion from 'const B' to incomplete type 'const
A'
const A &a = static_cast<const A&>(b);
^ ~
t.cc:1:7: note: forward declaration of 'A'
class A;
^
1 error generated.
$:
