Implement fixits for malformed 'main' declaration

[ggreif]

Bugzilla Link	8104
Version	trunk
OS	All
CC	@dwblaikie,@gribozavr

Extended Description

[7:30pm] gabor: dgregor: FixIt idea: error: C++ requires a type specifier for all declarations
[7:30pm] gabor: main (int , const char * argv [])
[7:30pm] gabor: ^--- "int "

Since main must return "int" this is an always applicable fixit.

I am not so sure with the main arguments

• either "int main(void)" in C++ also "int main()"
• or "int main(int argc, const char* argv[])"

But these are often mis-declared, so a fixit would be useful too.

[ggreif]

assigned to @dwblaikie

[dwblaikie]

I've made some progress on this already. r139282 implements fixits for declaring main 'virtual' and 'static'.

I'm also going to resolve llvm/llvm-bugzilla-archive#8269 as fixed/no repro because clang no longer suggests the wrong fixit (for the return type of main). In fact, it doesn't suggest any fixit at all - we should address that in this bug.

[assigning to myself since this bug is fairly old & seems untouched, so I assume it's not being actively worked on by the person currently assigned]

[dwblaikie]

Dmitri addressed another part of this in r172684, providing a fixit for an incorrect return type.

[gribozavr]

Added a fixit for _Noreturn in r173024.

[dwblaikie]

mentioned in issue llvm/llvm-bugzilla-archive#8269

[philnik777]

There are quite a few fixits now for misdeclared mains, so I think this can be closed.