From eafeb9a2676e16ed322e9e0695b5ce9407f5de8d Mon Sep 17 00:00:00 2001 From: Vadim Petrochenkov Date: Mon, 30 Dec 2019 21:38:43 +0300 Subject: [PATCH 1/3] expand/builtin_macros: Minor cleanup --- src/librustc_builtin_macros/util.rs | 2 +- src/librustc_expand/base.rs | 13 +++---------- src/librustc_feature/builtin_attrs.rs | 8 +------- 3 files changed, 5 insertions(+), 18 deletions(-) diff --git a/src/librustc_builtin_macros/util.rs b/src/librustc_builtin_macros/util.rs index 8ef76a8657e1e..b486eadd1a8be 100644 --- a/src/librustc_builtin_macros/util.rs +++ b/src/librustc_builtin_macros/util.rs @@ -6,7 +6,7 @@ use rustc_span::Symbol; pub fn check_builtin_macro_attribute(ecx: &ExtCtxt<'_>, meta_item: &MetaItem, name: Symbol) { // All the built-in macro attributes are "words" at the moment. - let template = AttributeTemplate::only_word(); + let template = AttributeTemplate { word: true, ..Default::default() }; let attr = ecx.attribute(meta_item.clone()); validate_attr::check_builtin_attribute(ecx.parse_sess, &attr, name, template); } diff --git a/src/librustc_expand/base.rs b/src/librustc_expand/base.rs index f15e626c2783b..55e9c70d63732 100644 --- a/src/librustc_expand/base.rs +++ b/src/librustc_expand/base.rs @@ -270,10 +270,9 @@ pub trait MultiItemModifier { ) -> Vec; } -impl MultiItemModifier for F +impl MultiItemModifier for F where - F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> T, - T: Into>, + F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> Vec, { fn expand( &self, @@ -282,13 +281,7 @@ where meta_item: &ast::MetaItem, item: Annotatable, ) -> Vec { - (*self)(ecx, span, meta_item, item).into() - } -} - -impl Into> for Annotatable { - fn into(self) -> Vec { - vec![self] + self(ecx, span, meta_item, item) } } diff --git a/src/librustc_feature/builtin_attrs.rs b/src/librustc_feature/builtin_attrs.rs index e9a5364c65838..e0e38c2dba941 100644 --- a/src/librustc_feature/builtin_attrs.rs +++ b/src/librustc_feature/builtin_attrs.rs @@ -85,19 +85,13 @@ impl AttributeGate { /// A template that the attribute input must match. /// Only top-level shape (`#[attr]` vs `#[attr(...)]` vs `#[attr = ...]`) is considered now. -#[derive(Clone, Copy)] +#[derive(Clone, Copy, Default)] pub struct AttributeTemplate { pub word: bool, pub list: Option<&'static str>, pub name_value_str: Option<&'static str>, } -impl AttributeTemplate { - pub fn only_word() -> Self { - Self { word: true, list: None, name_value_str: None } - } -} - /// A convenience macro for constructing attribute templates. /// E.g., `template!(Word, List: "description")` means that the attribute /// supports forms `#[attr]` and `#[attr(description)]`. From 552a8875bd5520c2e8c01ab05a12c304c730c5b9 Mon Sep 17 00:00:00 2001 From: Vadim Petrochenkov Date: Mon, 9 Mar 2020 20:50:12 +0300 Subject: [PATCH 2/3] expand: Implement support for retrying macro expansions --- src/librustc_builtin_macros/deriving/mod.rs | 6 +- src/librustc_expand/base.rs | 19 ++- src/librustc_expand/expand.rs | 145 ++++++++++++++------ src/librustc_expand/proc_macro.rs | 8 +- 4 files changed, 124 insertions(+), 54 deletions(-) diff --git a/src/librustc_builtin_macros/deriving/mod.rs b/src/librustc_builtin_macros/deriving/mod.rs index 5ba9d3800e118..b5ad67abf6201 100644 --- a/src/librustc_builtin_macros/deriving/mod.rs +++ b/src/librustc_builtin_macros/deriving/mod.rs @@ -2,7 +2,7 @@ use rustc_ast::ast::{self, ItemKind, MetaItem}; use rustc_ast::ptr::P; -use rustc_expand::base::{Annotatable, ExtCtxt, MultiItemModifier}; +use rustc_expand::base::{Annotatable, ExpandResult, ExtCtxt, MultiItemModifier}; use rustc_span::symbol::{sym, Symbol}; use rustc_span::Span; @@ -48,13 +48,13 @@ impl MultiItemModifier for BuiltinDerive { span: Span, meta_item: &MetaItem, item: Annotatable, - ) -> Vec { + ) -> ExpandResult, Annotatable> { // FIXME: Built-in derives often forget to give spans contexts, // so we are doing it here in a centralized way. let span = ecx.with_def_site_ctxt(span); let mut items = Vec::new(); (self.0)(ecx, span, meta_item, &item, &mut |a| items.push(a)); - items + ExpandResult::Ready(items) } } diff --git a/src/librustc_expand/base.rs b/src/librustc_expand/base.rs index 55e9c70d63732..3782746a57de4 100644 --- a/src/librustc_expand/base.rs +++ b/src/librustc_expand/base.rs @@ -258,8 +258,17 @@ impl Annotatable { } } -// `meta_item` is the annotation, and `item` is the item being modified. -// FIXME Decorators should follow the same pattern too. +/// Result of an expansion that may need to be retried. +/// Consider using this for non-`MultiItemModifier` expanders as well. +pub enum ExpandResult { + /// Expansion produced a result (possibly dummy). + Ready(T), + /// Expansion could not produce a result and needs to be retried. + /// The string is an explanation that will be printed if we are stuck in an infinite retry loop. + Retry(U, String), +} + +// `meta_item` is the attribute, and `item` is the item being modified. pub trait MultiItemModifier { fn expand( &self, @@ -267,7 +276,7 @@ pub trait MultiItemModifier { span: Span, meta_item: &ast::MetaItem, item: Annotatable, - ) -> Vec; + ) -> ExpandResult, Annotatable>; } impl MultiItemModifier for F @@ -280,8 +289,8 @@ where span: Span, meta_item: &ast::MetaItem, item: Annotatable, - ) -> Vec { - self(ecx, span, meta_item, item) + ) -> ExpandResult, Annotatable> { + ExpandResult::Ready(self(ecx, span, meta_item, item)) } } diff --git a/src/librustc_expand/expand.rs b/src/librustc_expand/expand.rs index effa89e8bfb21..f2af6755517f1 100644 --- a/src/librustc_expand/expand.rs +++ b/src/librustc_expand/expand.rs @@ -408,7 +408,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> { let mut undetermined_invocations = Vec::new(); let (mut progress, mut force) = (false, !self.monotonic); loop { - let invoc = if let Some(invoc) = invocations.pop() { + let (invoc, res) = if let Some(invoc) = invocations.pop() { invoc } else { self.resolve_imports(); @@ -420,30 +420,51 @@ impl<'a, 'b> MacroExpander<'a, 'b> { continue; }; - let eager_expansion_root = - if self.monotonic { invoc.expansion_data.id } else { orig_expansion_data.id }; - let res = match self.cx.resolver.resolve_macro_invocation( - &invoc, - eager_expansion_root, - force, - ) { - Ok(res) => res, - Err(Indeterminate) => { - undetermined_invocations.push(invoc); - continue; + let res = match res { + Some(res) => res, + None => { + let eager_expansion_root = if self.monotonic { + invoc.expansion_data.id + } else { + orig_expansion_data.id + }; + match self.cx.resolver.resolve_macro_invocation( + &invoc, + eager_expansion_root, + force, + ) { + Ok(res) => res, + Err(Indeterminate) => { + // Cannot resolve, will retry this invocation later. + undetermined_invocations.push((invoc, None)); + continue; + } + } } }; - progress = true; let ExpansionData { depth, id: expn_id, .. } = invoc.expansion_data; self.cx.current_expansion = invoc.expansion_data.clone(); // FIXME(jseyfried): Refactor out the following logic let (expanded_fragment, new_invocations) = match res { - InvocationRes::Single(ext) => { - let fragment = self.expand_invoc(invoc, &ext.kind); - self.collect_invocations(fragment, &[]) - } + InvocationRes::Single(ext) => match self.expand_invoc(invoc, &ext.kind) { + ExpandResult::Ready(fragment) => self.collect_invocations(fragment, &[]), + ExpandResult::Retry(invoc, explanation) => { + if force { + // We are stuck, stop retrying and produce a dummy fragment. + let span = invoc.span(); + self.cx.span_err(span, &explanation); + let fragment = invoc.fragment_kind.dummy(span); + self.collect_invocations(fragment, &[]) + } else { + // Cannot expand, will retry this invocation later. + undetermined_invocations + .push((invoc, Some(InvocationRes::Single(ext)))); + continue; + } + } + }, InvocationRes::DeriveContainer(_exts) => { // FIXME: Consider using the derive resolutions (`_exts`) immediately, // instead of enqueuing the derives to be resolved again later. @@ -463,14 +484,17 @@ impl<'a, 'b> MacroExpander<'a, 'b> { for path in derives { let expn_id = ExpnId::fresh(None); derive_placeholders.push(NodeId::placeholder_from_expn_id(expn_id)); - invocations.push(Invocation { - kind: InvocationKind::Derive { path, item: item.clone() }, - fragment_kind: invoc.fragment_kind, - expansion_data: ExpansionData { - id: expn_id, - ..invoc.expansion_data.clone() + invocations.push(( + Invocation { + kind: InvocationKind::Derive { path, item: item.clone() }, + fragment_kind: invoc.fragment_kind, + expansion_data: ExpansionData { + id: expn_id, + ..invoc.expansion_data.clone() + }, }, - }); + None, + )); } let fragment = invoc.fragment_kind.expect_from_annotatables(::std::iter::once(item)); @@ -478,6 +502,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> { } }; + progress = true; if expanded_fragments.len() < depth { expanded_fragments.push(Vec::new()); } @@ -535,7 +560,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> { &mut self, mut fragment: AstFragment, extra_placeholders: &[NodeId], - ) -> (AstFragment, Vec) { + ) -> (AstFragment, Vec<(Invocation, Option)>) { // Resolve `$crate`s in the fragment for pretty-printing. self.cx.resolver.resolve_dollar_crates(); @@ -635,13 +660,17 @@ impl<'a, 'b> MacroExpander<'a, 'b> { self.cx.trace_macros_diag(); } - fn expand_invoc(&mut self, invoc: Invocation, ext: &SyntaxExtensionKind) -> AstFragment { + fn expand_invoc( + &mut self, + invoc: Invocation, + ext: &SyntaxExtensionKind, + ) -> ExpandResult { if self.cx.current_expansion.depth > self.cx.ecfg.recursion_limit { self.error_recursion_limit_reached(); } let (fragment_kind, span) = (invoc.fragment_kind, invoc.span()); - match invoc.kind { + ExpandResult::Ready(match invoc.kind { InvocationKind::Bang { mac, .. } => match ext { SyntaxExtensionKind::Bang(expander) => { self.gate_proc_macro_expansion_kind(span, fragment_kind); @@ -663,7 +692,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> { } _ => unreachable!(), }, - InvocationKind::Attr { attr, mut item, .. } => match ext { + InvocationKind::Attr { attr, mut item, derives, after_derive } => match ext { SyntaxExtensionKind::Attr(expander) => { self.gate_proc_macro_input(&item); self.gate_proc_macro_attr_item(span, &item); @@ -679,8 +708,25 @@ impl<'a, 'b> MacroExpander<'a, 'b> { SyntaxExtensionKind::LegacyAttr(expander) => { match validate_attr::parse_meta(self.cx.parse_sess, &attr) { Ok(meta) => { - let item = expander.expand(self.cx, span, &meta, item); - fragment_kind.expect_from_annotatables(item) + let items = match expander.expand(self.cx, span, &meta, item) { + ExpandResult::Ready(items) => items, + ExpandResult::Retry(item, explanation) => { + // Reassemble the original invocation for retrying. + return ExpandResult::Retry( + Invocation { + kind: InvocationKind::Attr { + attr, + item, + derives, + after_derive, + }, + ..invoc + }, + explanation, + ); + } + }; + fragment_kind.expect_from_annotatables(items) } Err(mut err) => { err.emit(); @@ -702,19 +748,31 @@ impl<'a, 'b> MacroExpander<'a, 'b> { SyntaxExtensionKind::Derive(expander) | SyntaxExtensionKind::LegacyDerive(expander) => { if !item.derive_allowed() { - return fragment_kind.dummy(span); + return ExpandResult::Ready(fragment_kind.dummy(span)); } if let SyntaxExtensionKind::Derive(..) = ext { self.gate_proc_macro_input(&item); } let meta = ast::MetaItem { kind: ast::MetaItemKind::Word, span, path }; - let items = expander.expand(self.cx, span, &meta, item); + let items = match expander.expand(self.cx, span, &meta, item) { + ExpandResult::Ready(items) => items, + ExpandResult::Retry(item, explanation) => { + // Reassemble the original invocation for retrying. + return ExpandResult::Retry( + Invocation { + kind: InvocationKind::Derive { path: meta.path, item }, + ..invoc + }, + explanation, + ); + } + }; fragment_kind.expect_from_annotatables(items) } _ => unreachable!(), }, InvocationKind::DeriveContainer { .. } => unreachable!(), - } + }) } fn gate_proc_macro_attr_item(&self, span: Span, item: &Annotatable) { @@ -933,7 +991,7 @@ pub fn ensure_complete_parse<'a>( struct InvocationCollector<'a, 'b> { cx: &'a mut ExtCtxt<'b>, cfg: StripUnconfigured<'a>, - invocations: Vec, + invocations: Vec<(Invocation, Option)>, monotonic: bool, } @@ -955,15 +1013,18 @@ impl<'a, 'b> InvocationCollector<'a, 'b> { }; let expn_id = ExpnId::fresh(expn_data); let vis = kind.placeholder_visibility(); - self.invocations.push(Invocation { - kind, - fragment_kind, - expansion_data: ExpansionData { - id: expn_id, - depth: self.cx.current_expansion.depth + 1, - ..self.cx.current_expansion.clone() + self.invocations.push(( + Invocation { + kind, + fragment_kind, + expansion_data: ExpansionData { + id: expn_id, + depth: self.cx.current_expansion.depth + 1, + ..self.cx.current_expansion.clone() + }, }, - }); + None, + )); placeholder(fragment_kind, NodeId::placeholder_from_expn_id(expn_id), vis) } diff --git a/src/librustc_expand/proc_macro.rs b/src/librustc_expand/proc_macro.rs index 84a546345bb28..cb9afa4cd4f02 100644 --- a/src/librustc_expand/proc_macro.rs +++ b/src/librustc_expand/proc_macro.rs @@ -79,7 +79,7 @@ impl MultiItemModifier for ProcMacroDerive { span: Span, _meta_item: &ast::MetaItem, item: Annotatable, - ) -> Vec { + ) -> ExpandResult, Annotatable> { let item = match item { Annotatable::Arm(..) | Annotatable::Field(..) @@ -99,7 +99,7 @@ impl MultiItemModifier for ProcMacroDerive { "proc-macro derives may only be \ applied to a struct, enum, or union", ); - return Vec::new(); + return ExpandResult::Ready(Vec::new()); } }; match item.kind { @@ -110,7 +110,7 @@ impl MultiItemModifier for ProcMacroDerive { "proc-macro derives may only be \ applied to a struct, enum, or union", ); - return Vec::new(); + return ExpandResult::Ready(Vec::new()); } } @@ -158,7 +158,7 @@ impl MultiItemModifier for ProcMacroDerive { FatalError.raise(); } - items + ExpandResult::Ready(items) } } From 2e6528961c44a4f3841fd319af71f1d1a6af029c Mon Sep 17 00:00:00 2001 From: Vadim Petrochenkov Date: Tue, 10 Mar 2020 00:56:20 +0300 Subject: [PATCH 3/3] builtin_macros: Add attribute macro `#[cfg_accessible(path)]` --- src/libcore/macros/mod.rs | 12 +++++ src/libcore/prelude/v1.rs | 9 ++++ src/librustc_builtin_macros/cfg_accessible.rs | 54 +++++++++++++++++++ src/librustc_builtin_macros/lib.rs | 2 + src/librustc_expand/base.rs | 1 + src/librustc_resolve/macros.rs | 36 +++++++++++++ src/librustc_span/symbol.rs | 1 + src/libstd/lib.rs | 1 + src/libstd/prelude/v1.rs | 9 ++++ .../cfg_accessible-input-validation.rs | 24 +++++++++ .../cfg_accessible-input-validation.stderr | 44 +++++++++++++++ .../cfg_accessible-stuck.rs | 9 ++++ .../cfg_accessible-stuck.stderr | 14 +++++ .../cfg_accessible-unstable.rs | 2 + .../cfg_accessible-unstable.stderr | 12 +++++ .../conditional-compilation/cfg_accessible.rs | 43 +++++++++++++++ .../cfg_accessible.stderr | 38 +++++++++++++ 17 files changed, 311 insertions(+) create mode 100644 src/librustc_builtin_macros/cfg_accessible.rs create mode 100644 src/test/ui/conditional-compilation/cfg_accessible-input-validation.rs create mode 100644 src/test/ui/conditional-compilation/cfg_accessible-input-validation.stderr create mode 100644 src/test/ui/conditional-compilation/cfg_accessible-stuck.rs create mode 100644 src/test/ui/conditional-compilation/cfg_accessible-stuck.stderr create mode 100644 src/test/ui/conditional-compilation/cfg_accessible-unstable.rs create mode 100644 src/test/ui/conditional-compilation/cfg_accessible-unstable.stderr create mode 100644 src/test/ui/conditional-compilation/cfg_accessible.rs create mode 100644 src/test/ui/conditional-compilation/cfg_accessible.stderr diff --git a/src/libcore/macros/mod.rs b/src/libcore/macros/mod.rs index 76e58f0cc62bc..3b615a5246c29 100644 --- a/src/libcore/macros/mod.rs +++ b/src/libcore/macros/mod.rs @@ -1383,6 +1383,18 @@ pub(crate) mod builtin { /* compiler built-in */ } + /// Keeps the item it's applied to if the passed path is accessible, and removes it otherwise. + #[cfg(not(bootstrap))] + #[unstable( + feature = "cfg_accessible", + issue = "64797", + reason = "`cfg_accessible` is not fully implemented" + )] + #[rustc_builtin_macro] + pub macro cfg_accessible($item:item) { + /* compiler built-in */ + } + /// Unstable implementation detail of the `rustc` compiler, do not use. #[rustc_builtin_macro] #[stable(feature = "rust1", since = "1.0.0")] diff --git a/src/libcore/prelude/v1.rs b/src/libcore/prelude/v1.rs index 66b5a90b77b91..c91370b271992 100644 --- a/src/libcore/prelude/v1.rs +++ b/src/libcore/prelude/v1.rs @@ -67,3 +67,12 @@ pub use crate::{ pub use crate::macros::builtin::{ bench, global_allocator, test, test_case, RustcDecodable, RustcEncodable, }; + +#[cfg(not(bootstrap))] +#[unstable( + feature = "cfg_accessible", + issue = "64797", + reason = "`cfg_accessible` is not fully implemented" +)] +#[doc(no_inline)] +pub use crate::macros::builtin::cfg_accessible; diff --git a/src/librustc_builtin_macros/cfg_accessible.rs b/src/librustc_builtin_macros/cfg_accessible.rs new file mode 100644 index 0000000000000..3607a4d0d15b6 --- /dev/null +++ b/src/librustc_builtin_macros/cfg_accessible.rs @@ -0,0 +1,54 @@ +//! Implementation of the `#[cfg_accessible(path)]` attribute macro. + +use rustc_ast::ast; +use rustc_expand::base::{Annotatable, ExpandResult, ExtCtxt, MultiItemModifier}; +use rustc_feature::AttributeTemplate; +use rustc_parse::validate_attr; +use rustc_span::symbol::sym; +use rustc_span::Span; + +crate struct Expander; + +fn validate_input<'a>(ecx: &mut ExtCtxt<'_>, mi: &'a ast::MetaItem) -> Option<&'a ast::Path> { + match mi.meta_item_list() { + None => {} + Some([]) => ecx.span_err(mi.span, "`cfg_accessible` path is not specified"), + Some([_, .., l]) => ecx.span_err(l.span(), "multiple `cfg_accessible` paths are specified"), + Some([nmi]) => match nmi.meta_item() { + None => ecx.span_err(nmi.span(), "`cfg_accessible` path cannot be a literal"), + Some(mi) => { + if !mi.is_word() { + ecx.span_err(mi.span, "`cfg_accessible` path cannot accept arguments"); + } + return Some(&mi.path); + } + }, + } + None +} + +impl MultiItemModifier for Expander { + fn expand( + &self, + ecx: &mut ExtCtxt<'_>, + _span: Span, + meta_item: &ast::MetaItem, + item: Annotatable, + ) -> ExpandResult, Annotatable> { + let template = AttributeTemplate { list: Some("path"), ..Default::default() }; + let attr = &ecx.attribute(meta_item.clone()); + validate_attr::check_builtin_attribute(ecx.parse_sess, attr, sym::cfg_accessible, template); + + let path = match validate_input(ecx, meta_item) { + Some(path) => path, + None => return ExpandResult::Ready(Vec::new()), + }; + + let failure_msg = "cannot determine whether the path is accessible or not"; + match ecx.resolver.cfg_accessible(ecx.current_expansion.id, path) { + Ok(true) => ExpandResult::Ready(vec![item]), + Ok(false) => ExpandResult::Ready(Vec::new()), + Err(_) => ExpandResult::Retry(item, failure_msg.into()), + } + } +} diff --git a/src/librustc_builtin_macros/lib.rs b/src/librustc_builtin_macros/lib.rs index 9a8b0a87cb793..26a59c6b1bedb 100644 --- a/src/librustc_builtin_macros/lib.rs +++ b/src/librustc_builtin_macros/lib.rs @@ -22,6 +22,7 @@ use rustc_span::symbol::sym; mod asm; mod assert; mod cfg; +mod cfg_accessible; mod compile_error; mod concat; mod concat_idents; @@ -85,6 +86,7 @@ pub fn register_builtin_macros(resolver: &mut dyn Resolver, edition: Edition) { register_attr! { bench: test::expand_bench, + cfg_accessible: cfg_accessible::Expander, global_allocator: global_allocator::expand, test: test::expand_test, test_case: test::expand_test_case, diff --git a/src/librustc_expand/base.rs b/src/librustc_expand/base.rs index 3782746a57de4..4839651ac844b 100644 --- a/src/librustc_expand/base.rs +++ b/src/librustc_expand/base.rs @@ -897,6 +897,7 @@ pub trait Resolver { fn has_derive_copy(&self, expn_id: ExpnId) -> bool; fn add_derive_copy(&mut self, expn_id: ExpnId); + fn cfg_accessible(&mut self, expn_id: ExpnId, path: &ast::Path) -> Result; } #[derive(Clone)] diff --git a/src/librustc_resolve/macros.rs b/src/librustc_resolve/macros.rs index e11aec906693e..4e41ea82c47c9 100644 --- a/src/librustc_resolve/macros.rs +++ b/src/librustc_resolve/macros.rs @@ -339,6 +339,42 @@ impl<'a> base::Resolver for Resolver<'a> { fn add_derive_copy(&mut self, expn_id: ExpnId) { self.containers_deriving_copy.insert(expn_id); } + + // The function that implements the resolution logic of `#[cfg_accessible(path)]`. + // Returns true if the path can certainly be resolved in one of three namespaces, + // returns false if the path certainly cannot be resolved in any of the three namespaces. + // Returns `Indeterminate` if we cannot give a certain answer yet. + fn cfg_accessible(&mut self, expn_id: ExpnId, path: &ast::Path) -> Result { + let span = path.span; + let path = &Segment::from_path(path); + let parent_scope = self.invocation_parent_scopes[&expn_id]; + + let mut indeterminate = false; + for ns in [TypeNS, ValueNS, MacroNS].iter().copied() { + match self.resolve_path(path, Some(ns), &parent_scope, false, span, CrateLint::No) { + PathResult::Module(ModuleOrUniformRoot::Module(_)) => return Ok(true), + PathResult::NonModule(partial_res) if partial_res.unresolved_segments() == 0 => { + return Ok(true); + } + PathResult::Indeterminate => indeterminate = true, + // FIXME: `resolve_path` is not ready to report partially resolved paths + // correctly, so we just report an error if the path was reported as unresolved. + // This needs to be fixed for `cfg_accessible` to be useful. + PathResult::NonModule(..) | PathResult::Failed { .. } => {} + PathResult::Module(_) => panic!("unexpected path resolution"), + } + } + + if indeterminate { + return Err(Indeterminate); + } + + self.session + .struct_span_err(span, "not sure whether the path is accessible or not") + .span_note(span, "`cfg_accessible` is not fully implemented") + .emit(); + Ok(false) + } } impl<'a> Resolver<'a> { diff --git a/src/librustc_span/symbol.rs b/src/librustc_span/symbol.rs index c39f9f360c027..55284e73efcfa 100644 --- a/src/librustc_span/symbol.rs +++ b/src/librustc_span/symbol.rs @@ -181,6 +181,7 @@ symbols! { caller_location, cdylib, cfg, + cfg_accessible, cfg_attr, cfg_attr_multi, cfg_doctest, diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs index 784868b52e517..9950a8132555f 100644 --- a/src/libstd/lib.rs +++ b/src/libstd/lib.rs @@ -240,6 +240,7 @@ #![feature(atomic_mut_ptr)] #![feature(box_syntax)] #![feature(c_variadic)] +#![cfg_attr(not(bootstrap), feature(cfg_accessible))] #![feature(cfg_target_has_atomic)] #![feature(cfg_target_thread_local)] #![feature(char_error_internals)] diff --git a/src/libstd/prelude/v1.rs b/src/libstd/prelude/v1.rs index 7c0efe828c27a..6712f5ba5808c 100644 --- a/src/libstd/prelude/v1.rs +++ b/src/libstd/prelude/v1.rs @@ -53,6 +53,15 @@ pub use core::prelude::v1::{ PartialEq, PartialOrd, RustcDecodable, RustcEncodable, }; +#[cfg(not(bootstrap))] +#[unstable( + feature = "cfg_accessible", + issue = "64797", + reason = "`cfg_accessible` is not fully implemented" +)] +#[doc(hidden)] +pub use core::prelude::v1::cfg_accessible; + // The file so far is equivalent to src/libcore/prelude/v1.rs, // and below to src/liballoc/prelude.rs. // Those files are duplicated rather than using glob imports diff --git a/src/test/ui/conditional-compilation/cfg_accessible-input-validation.rs b/src/test/ui/conditional-compilation/cfg_accessible-input-validation.rs new file mode 100644 index 0000000000000..c51c908a4262e --- /dev/null +++ b/src/test/ui/conditional-compilation/cfg_accessible-input-validation.rs @@ -0,0 +1,24 @@ +#![feature(cfg_accessible)] + +#[cfg_accessible] //~ ERROR malformed `cfg_accessible` attribute input +struct S1; + +#[cfg_accessible = "value"] //~ ERROR malformed `cfg_accessible` attribute input +struct S2; + +#[cfg_accessible()] //~ ERROR `cfg_accessible` path is not specified +struct S3; + +#[cfg_accessible(std, core)] //~ ERROR multiple `cfg_accessible` paths are specified +struct S4; + +#[cfg_accessible("std")] //~ ERROR `cfg_accessible` path cannot be a literal +struct S5; + +#[cfg_accessible(std = "value")] //~ ERROR `cfg_accessible` path cannot accept arguments +struct S6; + +#[cfg_accessible(std(value))] //~ ERROR `cfg_accessible` path cannot accept arguments +struct S7; + +fn main() {} diff --git a/src/test/ui/conditional-compilation/cfg_accessible-input-validation.stderr b/src/test/ui/conditional-compilation/cfg_accessible-input-validation.stderr new file mode 100644 index 0000000000000..86706c766356e --- /dev/null +++ b/src/test/ui/conditional-compilation/cfg_accessible-input-validation.stderr @@ -0,0 +1,44 @@ +error: malformed `cfg_accessible` attribute input + --> $DIR/cfg_accessible-input-validation.rs:3:1 + | +LL | #[cfg_accessible] + | ^^^^^^^^^^^^^^^^^ help: must be of the form: `#[cfg_accessible(path)]` + +error: malformed `cfg_accessible` attribute input + --> $DIR/cfg_accessible-input-validation.rs:6:1 + | +LL | #[cfg_accessible = "value"] + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[cfg_accessible(path)]` + +error: `cfg_accessible` path is not specified + --> $DIR/cfg_accessible-input-validation.rs:9:1 + | +LL | #[cfg_accessible()] + | ^^^^^^^^^^^^^^^^^^^ + +error: multiple `cfg_accessible` paths are specified + --> $DIR/cfg_accessible-input-validation.rs:12:23 + | +LL | #[cfg_accessible(std, core)] + | ^^^^ + +error: `cfg_accessible` path cannot be a literal + --> $DIR/cfg_accessible-input-validation.rs:15:18 + | +LL | #[cfg_accessible("std")] + | ^^^^^ + +error: `cfg_accessible` path cannot accept arguments + --> $DIR/cfg_accessible-input-validation.rs:18:18 + | +LL | #[cfg_accessible(std = "value")] + | ^^^^^^^^^^^^^ + +error: `cfg_accessible` path cannot accept arguments + --> $DIR/cfg_accessible-input-validation.rs:21:18 + | +LL | #[cfg_accessible(std(value))] + | ^^^^^^^^^^ + +error: aborting due to 7 previous errors + diff --git a/src/test/ui/conditional-compilation/cfg_accessible-stuck.rs b/src/test/ui/conditional-compilation/cfg_accessible-stuck.rs new file mode 100644 index 0000000000000..8bc93fa324378 --- /dev/null +++ b/src/test/ui/conditional-compilation/cfg_accessible-stuck.rs @@ -0,0 +1,9 @@ +#![feature(cfg_accessible)] + +#[cfg_accessible(Z)] //~ ERROR cannot determine whether the path is accessible or not +struct S; + +#[cfg_accessible(S)] //~ ERROR cannot determine whether the path is accessible or not +struct Z; + +fn main() {} diff --git a/src/test/ui/conditional-compilation/cfg_accessible-stuck.stderr b/src/test/ui/conditional-compilation/cfg_accessible-stuck.stderr new file mode 100644 index 0000000000000..9641441a819b0 --- /dev/null +++ b/src/test/ui/conditional-compilation/cfg_accessible-stuck.stderr @@ -0,0 +1,14 @@ +error: cannot determine whether the path is accessible or not + --> $DIR/cfg_accessible-stuck.rs:6:1 + | +LL | #[cfg_accessible(S)] + | ^^^^^^^^^^^^^^^^^^^^ + +error: cannot determine whether the path is accessible or not + --> $DIR/cfg_accessible-stuck.rs:3:1 + | +LL | #[cfg_accessible(Z)] + | ^^^^^^^^^^^^^^^^^^^^ + +error: aborting due to 2 previous errors + diff --git a/src/test/ui/conditional-compilation/cfg_accessible-unstable.rs b/src/test/ui/conditional-compilation/cfg_accessible-unstable.rs new file mode 100644 index 0000000000000..e9247e67a2a26 --- /dev/null +++ b/src/test/ui/conditional-compilation/cfg_accessible-unstable.rs @@ -0,0 +1,2 @@ +#[cfg_accessible(std)] //~ ERROR use of unstable library feature 'cfg_accessible' +fn main() {} diff --git a/src/test/ui/conditional-compilation/cfg_accessible-unstable.stderr b/src/test/ui/conditional-compilation/cfg_accessible-unstable.stderr new file mode 100644 index 0000000000000..2f55b9559c78f --- /dev/null +++ b/src/test/ui/conditional-compilation/cfg_accessible-unstable.stderr @@ -0,0 +1,12 @@ +error[E0658]: use of unstable library feature 'cfg_accessible': `cfg_accessible` is not fully implemented + --> $DIR/cfg_accessible-unstable.rs:1:3 + | +LL | #[cfg_accessible(std)] + | ^^^^^^^^^^^^^^ + | + = note: see issue #64797 for more information + = help: add `#![feature(cfg_accessible)]` to the crate attributes to enable + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0658`. diff --git a/src/test/ui/conditional-compilation/cfg_accessible.rs b/src/test/ui/conditional-compilation/cfg_accessible.rs new file mode 100644 index 0000000000000..07b0be5b1ae26 --- /dev/null +++ b/src/test/ui/conditional-compilation/cfg_accessible.rs @@ -0,0 +1,43 @@ +#![feature(cfg_accessible)] + +mod m { + pub struct ExistingPublic; + struct ExistingPrivate; +} + +#[cfg_accessible(m::ExistingPublic)] +struct ExistingPublic; + +// FIXME: Not implemented yet. +#[cfg_accessible(m::ExistingPrivate)] //~ ERROR not sure whether the path is accessible or not +struct ExistingPrivate; + +// FIXME: Not implemented yet. +#[cfg_accessible(m::NonExistent)] //~ ERROR not sure whether the path is accessible or not +struct ExistingPrivate; + +#[cfg_accessible(n::AccessibleExpanded)] // OK, `cfg_accessible` can wait and retry. +struct AccessibleExpanded; + +macro_rules! generate_accessible_expanded { + () => { + mod n { + pub struct AccessibleExpanded; + } + }; +} + +generate_accessible_expanded!(); + +struct S { + field: u8, +} + +// FIXME: Not implemented yet. +#[cfg_accessible(S::field)] //~ ERROR not sure whether the path is accessible or not +struct Field; + +fn main() { + ExistingPublic; + AccessibleExpanded; +} diff --git a/src/test/ui/conditional-compilation/cfg_accessible.stderr b/src/test/ui/conditional-compilation/cfg_accessible.stderr new file mode 100644 index 0000000000000..167765cd66ee6 --- /dev/null +++ b/src/test/ui/conditional-compilation/cfg_accessible.stderr @@ -0,0 +1,38 @@ +error: not sure whether the path is accessible or not + --> $DIR/cfg_accessible.rs:12:18 + | +LL | #[cfg_accessible(m::ExistingPrivate)] + | ^^^^^^^^^^^^^^^^^^ + | +note: `cfg_accessible` is not fully implemented + --> $DIR/cfg_accessible.rs:12:18 + | +LL | #[cfg_accessible(m::ExistingPrivate)] + | ^^^^^^^^^^^^^^^^^^ + +error: not sure whether the path is accessible or not + --> $DIR/cfg_accessible.rs:16:18 + | +LL | #[cfg_accessible(m::NonExistent)] + | ^^^^^^^^^^^^^^ + | +note: `cfg_accessible` is not fully implemented + --> $DIR/cfg_accessible.rs:16:18 + | +LL | #[cfg_accessible(m::NonExistent)] + | ^^^^^^^^^^^^^^ + +error: not sure whether the path is accessible or not + --> $DIR/cfg_accessible.rs:37:18 + | +LL | #[cfg_accessible(S::field)] + | ^^^^^^^^ + | +note: `cfg_accessible` is not fully implemented + --> $DIR/cfg_accessible.rs:37:18 + | +LL | #[cfg_accessible(S::field)] + | ^^^^^^^^ + +error: aborting due to 3 previous errors +