-Wuninitialized suggests `= 0` for enums

[nico]

Bugzilla Link	9143
Resolution	FIXED
Resolved on	Feb 04, 2011 19:19
Version	trunk
OS	All
CC	@tkremenek

Extended Description

hummer:src thakis$ cat test.cc
enum A {
A_a, A_b
};
A f() {
A a;
return a;
}

hummer:src thakis$ ~/src/llvm-svn/Release+Asserts/bin/clang -c test.cc -Wall
test.cc:6:10: warning: variable 'a' is possibly uninitialized when used here [-Wuninitialized]
return a;
^
test.cc:5:3: note: variable 'a' is declared here
A a;
^
test.cc:5:6: note: add initialization to silence this warning
A a;
^
= 0
1 warning generated.

But doing this is of course not valid:

hummer:src thakis$ cat test.cc
enum A {
A_a, A_b
};
A f() {
A a = 0;
return a;
}
hummer:src thakis$ ~/src/llvm-svn/Release+Asserts/bin/clang -c test.cc -Wall
test.cc:5:5: error: cannot initialize a variable of type 'A' with an rvalue of type 'int'
A a = 0;
^ ~
1 error generated.

[nico]

assigned to @tkremenek

[tkremenek]

Fixed here:

r124924

Now no fixit is emitted. That seems like a reasonable tradeoff, since it isn't always clear what should be the "default" enum value.