Right now, `-Wformat` for a scoped enum will suggest a cast based on the
format specifier being used. This can lead to incorrect results, e.g.
attempting to format a scoped enum with `%s` would suggest casting to
`char *` instead of fixing the specifier. Change the logic to treat the
scoped enum's underlying type as the intended type to be printed, and
suggest format specifier changes and casts based on that.
`Lexer::getLocForEndOfToken` is documented as returning an invalid
source location when the end of the token is inside a macro expansion.
We don't want that for this particular application, so just calculate
the end location directly instead.
Before this, format fix-its would omit the closing parenthesis (thus
producing invalid code) for macros, e.g.:
```
$ cat format.cpp
extern "C" int printf(const char *, ...);
enum class Foo { Bar };
#define LOG(...) printf(__VA_ARGS__)
void f(Foo foo) { LOG("%d\n", foo); }
$ clang -fsyntax-only format.cpp
format.cpp:4:29: warning: format specifies type 'int' but the argument has type 'Foo' [-Wformat]
4 | void f(Foo f) { LOG("%d\n", f); }
| ~~ ^
| static_cast<int>(
format.cpp:3:25: note: expanded from macro 'LOG'
3 | #define LOG(...) printf(__VA_ARGS__)
| ^~~~~~~~~~~
1 warning generated.
```
We now emit a valid fix-it:
```
$ clang -fsyntax-only format.cpp
format.cpp:4:31: warning: format specifies type 'int' but the argument has type 'Foo' [-Wformat]
4 | void f(Foo foo) { LOG("%d\n", foo); }
| ~~ ^~~
| static_cast<int>( )
format.cpp:3:25: note: expanded from macro 'LOG'
3 | #define LOG(...) printf(__VA_ARGS__)
| ^~~~~~~~~~~
1 warning generated.
```
Fixes https://github.com/llvm/llvm-project/issues/63462
This helps transition code bases to handle the new warning added in 3632e2f5179
Before:
```
clang/test/FixIt/format.cpp:10:16: warning: format specifies type 'int' but the argument has type 'N::E' [-Wformat]
10 | printf("%d", N::E::One); // expected-warning{{format specifies type 'int' but the argument has type 'N::E'}}
| ~~ ^~~~~~~~~
| %d
```
After:
```
clang/test/FixIt/format.cpp:10:16: warning: format specifies type 'int' but the argument has type 'N::E' [-Wformat]
10 | printf("%d", N::E::One); // expected-warning{{format specifies type 'int' but the argument has type 'N::E'}}
| ~~ ^~~~~~~~~
| static_cast<int>( )
```
Differential Revision: https://reviews.llvm.org/D153623
