fn type_alias_(&mut self) -> WeldResult<TypeAlias> {
        self.consume(TType)?;
        let name = self.symbol()?;
        self.consume(TEqual)?;
        let ty = self.type_()?;
        self.consume(TSemicolon)?;
        Ok(TypeAlias {
            name: name.to_string(),
            ty,
        })
    }
Parse a single macro starting at the current position.
weld/src/syntax/parser.rs