From 4c37ad660714ab65d20226c743f686cf6174abc7 Mon Sep 17 00:00:00 2001 From: "Felix S. Klock II" Date: Tue, 17 May 2016 18:51:45 +0200 Subject: Add attribute support to generic lifetime and type parameters. I am using `ThinAttributes` rather than a vector for attributes attached to generics, since I expect almost all lifetime and types parameters to not carry any attributes. --- src/libsyntax/parse/parser.rs | 47 ++++++++++++++++++++++++++++++++++--------- 1 file changed, 38 insertions(+), 9 deletions(-) (limited to 'src/libsyntax/parse/parser.rs') diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index 23085fadc5e..fe5ff5c47b2 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -1184,7 +1184,7 @@ impl<'a> Parser<'a> { let lo = self.span.lo; let (name, node) = if self.eat_keyword(keywords::Type) { - let TyParam {ident, bounds, default, ..} = self.parse_ty_param()?; + let TyParam {ident, bounds, default, ..} = self.parse_ty_param(vec![])?; self.expect(&token::Semi)?; (ident, TraitItemKind::Type(bounds, default)) } else if self.is_const_item() { @@ -1923,10 +1923,22 @@ impl<'a> Parser<'a> { /// Parses `lifetime_defs = [ lifetime_defs { ',' lifetime_defs } ]` where `lifetime_def = /// lifetime [':' lifetimes]` - pub fn parse_lifetime_defs(&mut self) -> PResult<'a, Vec> { - + /// + /// If `followed_by_ty_params` is None, then we are in a context + /// where only lifetime parameters are allowed, and thus we should + /// error if we encounter attributes after the bound lifetimes. + /// + /// If `followed_by_ty_params` is Some(r), then there may be type + /// parameter bindings after the lifetimes, so we should pass + /// along the parsed attributes to be attached to the first such + /// type parmeter. + pub fn parse_lifetime_defs(&mut self, + followed_by_ty_params: Option<&mut Vec>) + -> PResult<'a, Vec> + { let mut res = Vec::new(); loop { + let attrs = self.parse_outer_attributes()?; match self.token { token::Lifetime(_) => { let lifetime = self.parse_lifetime()?; @@ -1936,11 +1948,20 @@ impl<'a> Parser<'a> { } else { Vec::new() }; - res.push(ast::LifetimeDef { lifetime: lifetime, + res.push(ast::LifetimeDef { attrs: attrs.into(), + lifetime: lifetime, bounds: bounds }); } _ => { + if let Some(recv) = followed_by_ty_params { + assert!(recv.is_empty()); + *recv = attrs; + } else { + let msg = "encountered trailing attributes after lifetime parameters"; + return Err(self.fatal(msg)); + } + debug!("parse_lifetime_defs ret {:?}", res); return Ok(res); } } @@ -4238,7 +4259,7 @@ impl<'a> Parser<'a> { } /// Matches typaram = IDENT (`?` unbound)? optbounds ( EQ ty )? - fn parse_ty_param(&mut self) -> PResult<'a, TyParam> { + fn parse_ty_param(&mut self, preceding_attrs: Vec) -> PResult<'a, TyParam> { let span = self.span; let ident = self.parse_ident()?; @@ -4252,6 +4273,7 @@ impl<'a> Parser<'a> { }; Ok(TyParam { + attrs: preceding_attrs.into(), ident: ident, id: ast::DUMMY_NODE_ID, bounds: bounds, @@ -4272,11 +4294,18 @@ impl<'a> Parser<'a> { let span_lo = self.span.lo; if self.eat(&token::Lt) { - let lifetime_defs = self.parse_lifetime_defs()?; + let mut attrs = vec![]; + let lifetime_defs = self.parse_lifetime_defs(Some(&mut attrs))?; let mut seen_default = false; + let mut post_lifetime_attrs = Some(attrs); let ty_params = self.parse_seq_to_gt(Some(token::Comma), |p| { p.forbid_lifetime()?; - let ty_param = p.parse_ty_param()?; + let attrs = match post_lifetime_attrs.as_mut() { + None => p.parse_outer_attributes()?, + Some(attrs) => mem::replace(attrs, vec![]), + }; + post_lifetime_attrs = None; + let ty_param = p.parse_ty_param(attrs)?; if ty_param.default.is_some() { seen_default = true; } else if seen_default { @@ -4433,7 +4462,7 @@ impl<'a> Parser<'a> { let bound_lifetimes = if self.eat_keyword(keywords::For) { // Higher ranked constraint. self.expect(&token::Lt)?; - let lifetime_defs = self.parse_lifetime_defs()?; + let lifetime_defs = self.parse_lifetime_defs(None)?; self.expect_gt()?; lifetime_defs } else { @@ -5006,7 +5035,7 @@ impl<'a> Parser<'a> { fn parse_late_bound_lifetime_defs(&mut self) -> PResult<'a, Vec> { if self.eat_keyword(keywords::For) { self.expect(&token::Lt)?; - let lifetime_defs = self.parse_lifetime_defs()?; + let lifetime_defs = self.parse_lifetime_defs(None)?; self.expect_gt()?; Ok(lifetime_defs) } else { -- cgit 1.4.1-3-g733a5 From 3a9b7be10b8e32d014008f9fde276cd032aa4e4a Mon Sep 17 00:00:00 2001 From: "Felix S. Klock II" Date: Mon, 11 Jul 2016 18:29:45 +0200 Subject: Added tests and fixed corner case for trailing attributes with no attached binding in generics. --- src/libsyntax/parse/parser.rs | 17 +++++++++++++- .../attrs-with-no-formal-in-generics-1.rs | 26 ++++++++++++++++++++++ .../attrs-with-no-formal-in-generics-2.rs | 26 ++++++++++++++++++++++ .../attrs-with-no-formal-in-generics-3.rs | 26 ++++++++++++++++++++++ 4 files changed, 94 insertions(+), 1 deletion(-) create mode 100644 src/test/compile-fail/attrs-with-no-formal-in-generics-1.rs create mode 100644 src/test/compile-fail/attrs-with-no-formal-in-generics-2.rs create mode 100644 src/test/compile-fail/attrs-with-no-formal-in-generics-3.rs (limited to 'src/libsyntax/parse/parser.rs') diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index fe5ff5c47b2..3c561780085 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -1958,7 +1958,7 @@ impl<'a> Parser<'a> { assert!(recv.is_empty()); *recv = attrs; } else { - let msg = "encountered trailing attributes after lifetime parameters"; + let msg = "trailing attribute after lifetime parameters"; return Err(self.fatal(msg)); } debug!("parse_lifetime_defs ret {:?}", res); @@ -4294,12 +4294,21 @@ impl<'a> Parser<'a> { let span_lo = self.span.lo; if self.eat(&token::Lt) { + // Upon encountering attribute in generics list, we do not + // know if it is attached to lifetime or to type param. + // + // Solution: 1. eagerly parse attributes in tandem with + // lifetime defs, 2. store last set of parsed (and unused) + // attributes in `attrs`, and 3. pass in those attributes + // when parsing formal type param after lifetime defs. let mut attrs = vec![]; let lifetime_defs = self.parse_lifetime_defs(Some(&mut attrs))?; let mut seen_default = false; let mut post_lifetime_attrs = Some(attrs); let ty_params = self.parse_seq_to_gt(Some(token::Comma), |p| { p.forbid_lifetime()?; + // Move out of `post_lifetime_attrs` if present. O/w + // not first type param: parse attributes anew. let attrs = match post_lifetime_attrs.as_mut() { None => p.parse_outer_attributes()?, Some(attrs) => mem::replace(attrs, vec![]), @@ -4315,6 +4324,12 @@ impl<'a> Parser<'a> { } Ok(ty_param) })?; + if let Some(attrs) = post_lifetime_attrs { + if !attrs.is_empty() { + self.span_err(attrs[0].span, + "trailing attribute after lifetime parameters"); + } + } Ok(ast::Generics { lifetimes: lifetime_defs, ty_params: ty_params, diff --git a/src/test/compile-fail/attrs-with-no-formal-in-generics-1.rs b/src/test/compile-fail/attrs-with-no-formal-in-generics-1.rs new file mode 100644 index 00000000000..53e287cda20 --- /dev/null +++ b/src/test/compile-fail/attrs-with-no-formal-in-generics-1.rs @@ -0,0 +1,26 @@ +// Copyright 2016 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// This test checks variations on `<#[attr] 'a, #[oops]>`, where +// `#[oops]` is left dangling (that is, it is unattached, with no +// formal binding following it). + +#![feature(generic_param_attrs, rustc_attrs)] +#![allow(dead_code)] + +struct RefIntPair<'a, 'b>(&'a u32, &'b u32); + +impl<#[rustc_1] 'a, 'b, #[oops]> RefIntPair<'a, 'b> { + //~^ ERROR trailing attribute after lifetime parameters +} + +fn main() { + +} diff --git a/src/test/compile-fail/attrs-with-no-formal-in-generics-2.rs b/src/test/compile-fail/attrs-with-no-formal-in-generics-2.rs new file mode 100644 index 00000000000..a38a7bfb937 --- /dev/null +++ b/src/test/compile-fail/attrs-with-no-formal-in-generics-2.rs @@ -0,0 +1,26 @@ +// Copyright 2016 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// This test checks variations on `<#[attr] 'a, #[oops]>`, where +// `#[oops]` is left dangling (that is, it is unattached, with no +// formal binding following it). + +#![feature(generic_param_attrs, rustc_attrs)] +#![allow(dead_code)] + +struct RefAny<'a, T>(&'a T); + +impl<#[rustc_1] 'a, #[rustc_2] T, #[oops]> RefAny<'a, T> { + //~^ ERROR expected identifier, found `>` +} + +fn main() { + +} diff --git a/src/test/compile-fail/attrs-with-no-formal-in-generics-3.rs b/src/test/compile-fail/attrs-with-no-formal-in-generics-3.rs new file mode 100644 index 00000000000..e7d5b94d242 --- /dev/null +++ b/src/test/compile-fail/attrs-with-no-formal-in-generics-3.rs @@ -0,0 +1,26 @@ +// Copyright 2016 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// This test checks variations on `<#[attr] 'a, #[oops]>`, where +// `#[oops]` is left dangling (that is, it is unattached, with no +// formal binding following it). + +struct RefIntPair<'a, 'b>(&'a u32, &'b u32); + +fn hof_lt(_: Q) + where Q: for <#[rustc_1] 'a, 'b, #[oops]> Fn(RefIntPair<'a,'b>) -> &'b u32 + //~^ ERROR trailing attribute after lifetime parameters +{ + +} + +fn main() { + +} -- cgit 1.4.1-3-g733a5