diff options
Diffstat (limited to 'src/libsyntax/feature_gate.rs')
| -rw-r--r-- | src/libsyntax/feature_gate.rs | 252 |
1 files changed, 201 insertions, 51 deletions
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs index fd1ca11818c..3bebba15a57 100644 --- a/src/libsyntax/feature_gate.rs +++ b/src/libsyntax/feature_gate.rs @@ -23,6 +23,7 @@ //! becomes stable. use self::Status::*; +use self::AttributeType::*; use abi::RustIntrinsic; use ast::NodeId; @@ -35,7 +36,6 @@ use visit; use visit::Visitor; use parse::token::{self, InternedString}; -use std::slice; use std::ascii::AsciiExt; // If you change this list without updating src/doc/reference.md, @cmr will be sad @@ -133,6 +133,12 @@ static KNOWN_FEATURES: &'static [(&'static str, &'static str, Status)] = &[ // Allows using the unsafe_no_drop_flag attribute (unlikely to // switch to Accepted; see RFC 320) ("unsafe_no_drop_flag", "1.0.0", Active), + + // Allows the use of custom attributes; RFC 572 + ("custom_attribute", "1.0.0", Active), + + // Allows the use of rustc_* attributes; RFC 572 + ("rustc_attrs", "1.0.0", Active), ]; // (changing above list without updating src/doc/reference.md makes @cmr sad) @@ -152,12 +158,148 @@ enum Status { Accepted, } +// Attributes that have a special meaning to rustc or rustdoc +pub static KNOWN_ATTRIBUTES: &'static [(&'static str, AttributeType)] = &[ + // Normal attributes + + ("warn", Normal), + ("allow", Normal), + ("forbid", Normal), + ("deny", Normal), + + ("macro_reexport", Normal), + ("macro_use", Normal), + ("macro_export", Normal), + ("plugin_registrar", Normal), + + ("cfg", Normal), + ("main", Normal), + ("start", Normal), + ("test", Normal), + ("bench", Normal), + ("simd", Normal), + ("repr", Normal), + ("path", Normal), + ("abi", Normal), + ("unsafe_destructor", Normal), + ("automatically_derived", Normal), + ("no_mangle", Normal), + ("no_link", Normal), + ("derive", Normal), + ("should_fail", Normal), + ("ignore", Normal), + ("no_implicit_prelude", Normal), + ("reexport_test_harness_main", Normal), + ("link_args", Normal), + ("macro_escape", Normal), + + + ("staged_api", Gated("staged_api", + "staged_api is for use by rustc only")), + ("plugin", Gated("plugin", + "compiler plugins are experimental \ + and possibly buggy")), + ("no_std", Gated("no_std", + "no_std is experimental")), + ("lang", Gated("lang_items", + "language items are subject to change")), + ("linkage", Gated("linkage", + "the `linkage` attribute is experimental \ + and not portable across platforms")), + ("thread_local", Gated("thread_local", + "`#[thread_local]` is an experimental feature, and does not \ + currently handle destructors. There is no corresponding \ + `#[task_local]` mapping to the task model")), + + ("rustc_on_unimplemented", Gated("on_unimplemented", + "the `#[rustc_on_unimplemented]` attribute \ + is an experimental feature")), + ("rustc_variance", Gated("rustc_attrs", + "the `#[rustc_variance]` attribute \ + is an experimental feature")), + ("rustc_error", Gated("rustc_attrs", + "the `#[rustc_error]` attribute \ + is an experimental feature")), + ("rustc_move_fragments", Gated("rustc_attrs", + "the `#[rustc_move_fragments]` attribute \ + is an experimental feature")), + + // FIXME: #14408 whitelist docs since rustdoc looks at them + ("doc", Whitelisted), + + // FIXME: #14406 these are processed in trans, which happens after the + // lint pass + ("cold", Whitelisted), + ("export_name", Whitelisted), + ("inline", Whitelisted), + ("link", Whitelisted), + ("link_name", Whitelisted), + ("link_section", Whitelisted), + ("no_builtins", Whitelisted), + ("no_mangle", Whitelisted), + ("no_split_stack", Whitelisted), + ("no_stack_check", Whitelisted), + ("packed", Whitelisted), + ("static_assert", Whitelisted), + ("no_debug", Whitelisted), + ("omit_gdb_pretty_printer_section", Whitelisted), + ("unsafe_no_drop_flag", Whitelisted), + + // used in resolve + ("prelude_import", Whitelisted), + + // FIXME: #14407 these are only looked at on-demand so we can't + // guarantee they'll have already been checked + ("deprecated", Whitelisted), + ("must_use", Whitelisted), + ("stable", Whitelisted), + ("unstable", Whitelisted), + + // FIXME: #19470 this shouldn't be needed forever + ("old_orphan_check", Whitelisted), + ("old_impl_check", Whitelisted), + ("rustc_paren_sugar", Whitelisted), // FIXME: #18101 temporary unboxed closure hack + + // Crate level attributes + ("crate_name", CrateLevel), + ("crate_type", CrateLevel), + ("crate_id", CrateLevel), + ("feature", CrateLevel), + ("no_start", CrateLevel), + ("no_main", CrateLevel), + ("no_builtins", CrateLevel), + ("recursion_limit", CrateLevel), +]; + +#[derive(PartialEq, Copy)] +pub enum AttributeType { + /// Normal, builtin attribute that is consumed + /// by the compiler before the unused_attribute check + Normal, + + /// Builtin attribute that may not be consumed by the compiler + /// before the unused_attribute check. These attributes + /// will be ignored by the unused_attribute lint + Whitelisted, + + /// Is gated by a given feature gate and reason + /// These get whitelisted too + Gated(&'static str, &'static str), + + /// Builtin attribute that is only allowed at the crate level + CrateLevel, +} + /// A set of features to be used by later passes. pub struct Features { pub unboxed_closures: bool, pub rustc_diagnostic_macros: bool, pub visible_private_types: bool, - pub quote: bool, + pub allow_quote: bool, + pub allow_asm: bool, + pub allow_log_syntax: bool, + pub allow_concat_idents: bool, + pub allow_trace_macros: bool, pub old_orphan_check: bool, pub simd_ffi: bool, pub unmarked_api: bool, @@ -173,7 +315,11 @@ impl Features { unboxed_closures: false, rustc_diagnostic_macros: false, visible_private_types: false, - quote: false, + allow_quote: false, + allow_asm: false, + allow_log_syntax: false, + allow_concat_idents: false, + allow_trace_macros: false, old_orphan_check: false, simd_ffi: false, unmarked_api: false, @@ -222,6 +368,18 @@ pub fn emit_feature_warn(diag: &SpanHandler, feature: &str, span: Span, explain: } } +pub const EXPLAIN_ASM: &'static str = + "inline assembly is not stable enough for use and is subject to change"; + +pub const EXPLAIN_LOG_SYNTAX: &'static str = + "`log_syntax!` is not stable enough for use and is subject to change"; + +pub const EXPLAIN_CONCAT_IDENTS: &'static str = + "`concat_idents` is not stable enough for use and is subject to change"; + +pub const EXPLAIN_TRACE_MACROS: &'static str = + "`trace_macros` is not stable enough for use and is subject to change"; + struct MacroVisitor<'a> { context: &'a Context<'a> } @@ -231,24 +389,28 @@ impl<'a, 'v> Visitor<'v> for MacroVisitor<'a> { let ast::MacInvocTT(ref path, _, _) = mac.node; let id = path.segments.last().unwrap().identifier; + // Issue 22234: If you add a new case here, make sure to also + // add code to catch the macro during or after expansion. + // + // We still keep this MacroVisitor (rather than *solely* + // relying on catching cases during or after expansion) to + // catch uses of these macros within conditionally-compiled + // code, e.g. `#[cfg]`-guarded functions. + if id == token::str_to_ident("asm") { - self.context.gate_feature("asm", path.span, "inline assembly is not \ - stable enough for use and is subject to change"); + self.context.gate_feature("asm", path.span, EXPLAIN_ASM); } else if id == token::str_to_ident("log_syntax") { - self.context.gate_feature("log_syntax", path.span, "`log_syntax!` is not \ - stable enough for use and is subject to change"); + self.context.gate_feature("log_syntax", path.span, EXPLAIN_LOG_SYNTAX); } else if id == token::str_to_ident("trace_macros") { - self.context.gate_feature("trace_macros", path.span, "`trace_macros` is not \ - stable enough for use and is subject to change"); + self.context.gate_feature("trace_macros", path.span, EXPLAIN_TRACE_MACROS); } else if id == token::str_to_ident("concat_idents") { - self.context.gate_feature("concat_idents", path.span, "`concat_idents` is not \ - stable enough for use and is subject to change"); + self.context.gate_feature("concat_idents", path.span, EXPLAIN_CONCAT_IDENTS); } } } @@ -274,22 +436,6 @@ impl<'a, 'v> Visitor<'v> for PostExpansionVisitor<'a> { } fn visit_item(&mut self, i: &ast::Item) { - for attr in &i.attrs { - if attr.name() == "thread_local" { - self.gate_feature("thread_local", i.span, - "`#[thread_local]` is an experimental feature, and does not \ - currently handle destructors. There is no corresponding \ - `#[task_local]` mapping to the task model"); - } else if attr.name() == "linkage" { - self.gate_feature("linkage", i.span, - "the `linkage` attribute is experimental \ - and not portable across platforms") - } else if attr.name() == "rustc_on_unimplemented" { - self.gate_feature("on_unimplemented", i.span, - "the `#[rustc_on_unimplemented]` attribute \ - is an experimental feature") - } - } match i.node { ast::ItemExternCrate(_) => { if attr::contains_name(&i.attrs[], "macro_reexport") { @@ -463,30 +609,27 @@ impl<'a, 'v> Visitor<'v> for PostExpansionVisitor<'a> { } fn visit_attribute(&mut self, attr: &ast::Attribute) { - if attr.check_name("staged_api") { - self.gate_feature("staged_api", attr.span, - "staged_api is for use by rustc only"); - } else if attr.check_name("plugin") { - self.gate_feature("plugin", attr.span, - "compiler plugins are experimental \ - and possibly buggy"); - } - - if attr::contains_name(slice::ref_slice(attr), "lang") { - self.gate_feature("lang_items", - attr.span, - "language items are subject to change"); - } - - if attr.check_name("no_std") { - self.gate_feature("no_std", attr.span, - "no_std is experimental"); + let name = &*attr.name(); + for &(n, ty) in KNOWN_ATTRIBUTES { + if n == name { + if let Gated(gate, desc) = ty { + self.gate_feature(gate, attr.span, desc); + } + return; + } } - - if attr.check_name("unsafe_no_drop_flag") { - self.gate_feature("unsafe_no_drop_flag", attr.span, - "unsafe_no_drop_flag has unstable semantics \ - and may be removed in the future"); + if name.starts_with("rustc_") { + self.gate_feature("rustc_attrs", attr.span, + "unless otherwise specified, attributes \ + with the prefix `rustc_` \ + are reserved for internal compiler diagnostics"); + } else { + self.gate_feature("custom_attribute", attr.span, + format!("The attribute `{}` is currently \ + unknown to the the compiler and \ + may have meaning \ + added to it in the future", + name).as_slice()); } } @@ -591,11 +734,18 @@ fn check_crate_inner<F>(cm: &CodeMap, span_handler: &SpanHandler, krate: &ast::C check(&mut cx, krate); + // FIXME (pnkfelix): Before adding the 99th entry below, change it + // to a single-pass (instead of N calls to `.has_feature`). + Features { unboxed_closures: cx.has_feature("unboxed_closures"), rustc_diagnostic_macros: cx.has_feature("rustc_diagnostic_macros"), visible_private_types: cx.has_feature("visible_private_types"), - quote: cx.has_feature("quote"), + allow_quote: cx.has_feature("quote"), + allow_asm: cx.has_feature("asm"), + allow_log_syntax: cx.has_feature("log_syntax"), + allow_concat_idents: cx.has_feature("concat_idents"), + allow_trace_macros: cx.has_feature("trace_macros"), old_orphan_check: cx.has_feature("old_orphan_check"), simd_ffi: cx.has_feature("simd_ffi"), unmarked_api: cx.has_feature("unmarked_api"), |