rust/tests/ui/macros/lint-trailing-macro-call.rs

// check-pass
//
// Ensures that we properly lint
// a removed 'expression' resulting from a macro
// in trailing expression position

macro_rules! expand_it {
    () => {
        #[cfg(FALSE)] 25; //~  WARN trailing semicolon in macro
                          //~| WARN this was previously
    }
}

fn main() {
    expand_it!()
}
Fix linting when trailing macro expands to a trailing semi When a macro is used in the trailing expression position of a block (e.g. `fn foo() { my_macro!() }`), we currently parse it as an expression, rather than a statement. As a result, we ended up using the `NodeId` of the containing statement as our `lint_node_id`, even though we don't normally do this for macro calls. If such a macro expands to an expression with a `#[cfg]` attribute, then the trailing statement can get removed entirely. This lead to an ICE, since we were usng the `NodeId` of the expression to emit a lint. Ths commit makes us skip updating `lint_node_id` when handling a macro in trailing expression position. This will cause us to lint at the closest parent of the macro call. 2021-09-16 00:32:03 +00:00			`// check-pass`
			`//`
			`// Ensures that we properly lint`
			`// a removed 'expression' resulting from a macro`
			`// in trailing expression position`

			`macro_rules! expand_it {`
			`() => {`
			`#[cfg(FALSE)] 25; //~ WARN trailing semicolon in macro`
			`//~\| WARN this was previously`
			`}`
			`}`

			`fn main() {`
			`expand_it!()`
			`}`