rust/src/test/ui/parser/no-const-fn-in-extern-block.rs

extern {
    const fn foo();
    //~^ ERROR functions in `extern` blocks cannot have qualifiers
    const unsafe fn bar();
    //~^ ERROR functions in `extern` blocks cannot have qualifiers
}

fn main() {}
Add support for 'extern const fn' This works just as you might expect - an 'extern const fn' is a 'const fn' that is callable from foreign code. Currently, panicking is not allowed in consts. When RFC 2345 is stabilized, then panicking in an 'extern const fn' will produce a compile-time error when invoked at compile time, and an abort when invoked at runtime. Since this is extending the language (we're allowing the `const` keyword in a new context), I believe that this will need an FCP. However, it's a very minor change, so I didn't think that filing an RFC was necessary. This will allow libc (and other FFI crates) to make many functions `const`, without having to give up on making them `extern` as well. 2019-09-29 18:22:18 -05:00			`extern {`
			`const fn foo();`
parser: merge `fn` grammars wrt. bodies & headers also refactor `FnKind` and `visit_assoc_item` visitors 2020-01-29 17:18:54 -06:00			//~^ ERROR functions in `extern` blocks cannot have qualifiers
Add support for 'extern const fn' This works just as you might expect - an 'extern const fn' is a 'const fn' that is callable from foreign code. Currently, panicking is not allowed in consts. When RFC 2345 is stabilized, then panicking in an 'extern const fn' will produce a compile-time error when invoked at compile time, and an abort when invoked at runtime. Since this is extending the language (we're allowing the `const` keyword in a new context), I believe that this will need an FCP. However, it's a very minor change, so I didn't think that filing an RFC was necessary. This will allow libc (and other FFI crates) to make many functions `const`, without having to give up on making them `extern` as well. 2019-09-29 18:22:18 -05:00			`const unsafe fn bar();`
parser: merge `fn` grammars wrt. bodies & headers also refactor `FnKind` and `visit_assoc_item` visitors 2020-01-29 17:18:54 -06:00			//~^ ERROR functions in `extern` blocks cannot have qualifiers
Add support for 'extern const fn' This works just as you might expect - an 'extern const fn' is a 'const fn' that is callable from foreign code. Currently, panicking is not allowed in consts. When RFC 2345 is stabilized, then panicking in an 'extern const fn' will produce a compile-time error when invoked at compile time, and an abort when invoked at runtime. Since this is extending the language (we're allowing the `const` keyword in a new context), I believe that this will need an FCP. However, it's a very minor change, so I didn't think that filing an RFC was necessary. This will allow libc (and other FFI crates) to make many functions `const`, without having to give up on making them `extern` as well. 2019-09-29 18:22:18 -05:00			`}`

			`fn main() {}`