Make various fixes:
- add feature gate - add basic tests - adjust parser to eliminate conflict between `const fn` and associated constants - allow `const fn` in traits/trait-impls, but forbid later in type check - correct some merge conflicts
This commit is contained in:
Niko Matsakis
parent
fb206bf34a
commit
df93deab10
36 changed files with 322 additions and 108 deletions
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@ -1160,7 +1160,8 @@ impl<'a> Parser<'a> {
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let TyParam {ident, bounds, default, ..} = try!(p.parse_ty_param());
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try!(p.expect(&token::Semi));
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(ident, TypeTraitItem(bounds, default))
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} else if try!(p.eat_keyword(keywords::Const)) {
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} else if p.is_const_item() {
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try!(p.expect_keyword(keywords::Const));
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let ident = try!(p.parse_ident());
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try!(p.expect(&token::Colon));
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let ty = try!(p.parse_ty_sum());
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@ -1175,13 +1176,7 @@ impl<'a> Parser<'a> {
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};
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(ident, ConstTraitItem(ty, default))
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} else {
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let unsafety = try!(p.parse_unsafety());
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let abi = if try!(p.eat_keyword(keywords::Extern)) {
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try!(p.parse_opt_abi()).unwrap_or(abi::C)
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} else {
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abi::Rust
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};
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try!(p.expect_keyword(keywords::Fn));
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let (constness, unsafety, abi) = try!(p.parse_fn_front_matter());
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let ident = try!(p.parse_ident());
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let mut generics = try!(p.parse_generics());
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@ -1196,7 +1191,7 @@ impl<'a> Parser<'a> {
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generics.where_clause = try!(p.parse_where_clause());
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let sig = ast::MethodSig {
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unsafety: unsafety,
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constness: ast::Constness::NotConst;
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constness: constness,
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decl: d,
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generics: generics,
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abi: abi,
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@ -4372,6 +4367,36 @@ impl<'a> Parser<'a> {
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Ok((ident, ItemFn(decl, unsafety, constness, abi, generics, body), Some(inner_attrs)))
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}
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/// true if we are looking at `const ID`, false for things like `const fn` etc
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pub fn is_const_item(&mut self) -> bool {
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self.token.is_keyword(keywords::Const) &&
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!self.look_ahead(1, |t| t.is_keyword(keywords::Fn))
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}
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/// parses all the "front matter" for a `fn` declaration, up to
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/// and including the `fn` keyword:
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///
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/// - `const fn`
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/// - `unsafe fn`
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/// - `extern fn`
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/// - etc
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pub fn parse_fn_front_matter(&mut self) -> PResult<(ast::Constness, ast::Unsafety, abi::Abi)> {
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let is_const_fn = try!(self.eat_keyword(keywords::Const));
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let (constness, unsafety, abi) = if is_const_fn {
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(Constness::Const, Unsafety::Normal, abi::Rust)
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} else {
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let unsafety = try!(self.parse_unsafety());
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let abi = if try!(self.eat_keyword(keywords::Extern)) {
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try!(self.parse_opt_abi()).unwrap_or(abi::C)
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} else {
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abi::Rust
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};
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(Constness::NotConst, unsafety, abi)
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};
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try!(self.expect_keyword(keywords::Fn));
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Ok((constness, unsafety, abi))
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}
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/// Parse an impl item.
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pub fn parse_impl_item(&mut self) -> PResult<P<ImplItem>> {
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maybe_whole!(no_clone self, NtImplItem);
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@ -4385,7 +4410,8 @@ impl<'a> Parser<'a> {
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let typ = try!(self.parse_ty_sum());
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try!(self.expect(&token::Semi));
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(name, TypeImplItem(typ))
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} else if try!(self.eat_keyword(keywords::Const)) {
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} else if self.is_const_item() {
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try!(self.expect_keyword(keywords::Const));
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let name = try!(self.parse_ident());
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try!(self.expect(&token::Colon));
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let typ = try!(self.parse_ty_sum());
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@ -4450,19 +4476,7 @@ impl<'a> Parser<'a> {
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}
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Ok((token::special_idents::invalid, vec![], ast::MacImplItem(m)))
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} else {
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let is_const_fn = !is_trait_impl && self.eat_keyword(keywords::Const);
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let (constness, unsafety, abi) = if is_const_fn {
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(Constness::Const, Unsafety::Normal, abi::Rust)
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} else {
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let unsafety = try!(self.parse_unsafety());
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let abi = if try!(self.eat_keyword(keywords::Extern)) {
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try!(self.parse_opt_abi()).unwrap_or(abi::C)
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} else {
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abi::Rust
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};
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(Constness::NotConst, unsafety, abi)
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};
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try!(self.expect_keyword(keywords::Fn));
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let (constness, unsafety, abi) = try!(self.parse_fn_front_matter());
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let ident = try!(self.parse_ident());
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let mut generics = try!(self.parse_generics());
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let (explicit_self, decl) = try!(self.parse_fn_decl_with_self(|p| {
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@ -4475,7 +4489,7 @@ impl<'a> Parser<'a> {
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abi: abi,
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explicit_self: explicit_self,
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unsafety: unsafety,
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constness: constness;
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constness: constness,
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decl: decl
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}, body)))
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}
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@ -5301,9 +5315,9 @@ impl<'a> Parser<'a> {
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if try!(self.eat_keyword(keywords::Const) ){
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if self.check_keyword(keywords::Fn) {
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// CONST FUNCTION ITEM
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self.bump();
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try!(self.bump());
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let (ident, item_, extra_attrs) =
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self.parse_item_fn(Unsafety::Normal, Constness::Const, abi::Rust);
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try!(self.parse_item_fn(Unsafety::Normal, Constness::Const, abi::Rust));
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let last_span = self.last_span;
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let item = self.mk_item(lo,
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last_span.hi,
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@ -5311,7 +5325,7 @@ impl<'a> Parser<'a> {
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item_,
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visibility,
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maybe_append(attrs, extra_attrs));
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return Ok(item);
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return Ok(Some(item));
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}
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// CONST ITEM
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