From fd4dd00ddef578aa01744e4146c1dfe3fbca4866 Mon Sep 17 00:00:00 2001 From: David Tolnay Date: Sun, 23 Aug 2020 03:42:19 -0700 Subject: [PATCH] Syntactically permit unsafety on mods --- compiler/rustc_ast/src/ast.rs | 10 ++- compiler/rustc_ast/src/mut_visit.rs | 7 +- .../rustc_ast_passes/src/ast_validation.rs | 10 ++- compiler/rustc_ast_pretty/src/pprust.rs | 11 ++- compiler/rustc_expand/src/config.rs | 2 +- compiler/rustc_expand/src/expand.rs | 27 ++++-- compiler/rustc_expand/src/module.rs | 12 ++- compiler/rustc_parse/src/parser/item.rs | 67 ++++++++++---- .../ast-json/ast-json-noexpand-output.stdout | 2 +- src/test/ui/ast-json/ast-json-output.stdout | 2 +- src/test/ui/parser/unsafe-foreign-mod.rs | 9 ++ src/test/ui/parser/unsafe-foreign-mod.stderr | 14 +++ src/test/ui/parser/unsafe-mod.rs | 9 ++ src/test/ui/parser/unsafe-mod.stderr | 23 +++++ .../proc-macro/auxiliary/macro-only-syntax.rs | 89 +++++++++++++++++++ src/test/ui/proc-macro/unsafe-foreign-mod.rs | 14 +++ src/test/ui/proc-macro/unsafe-mod.rs | 13 +++ 17 files changed, 284 insertions(+), 37 deletions(-) create mode 100644 src/test/ui/parser/unsafe-foreign-mod.rs create mode 100644 src/test/ui/parser/unsafe-foreign-mod.stderr create mode 100644 src/test/ui/parser/unsafe-mod.rs create mode 100644 src/test/ui/parser/unsafe-mod.stderr create mode 100644 src/test/ui/proc-macro/auxiliary/macro-only-syntax.rs create mode 100644 src/test/ui/proc-macro/unsafe-foreign-mod.rs create mode 100644 src/test/ui/proc-macro/unsafe-mod.rs diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs index 49aa1fc17357e..b9f380dc4e835 100644 --- a/compiler/rustc_ast/src/ast.rs +++ b/compiler/rustc_ast/src/ast.rs @@ -2289,12 +2289,15 @@ impl FnRetTy { /// Module declaration. /// /// E.g., `mod foo;` or `mod foo { .. }`. -#[derive(Clone, Encodable, Decodable, Debug, Default)] +#[derive(Clone, Encodable, Decodable, Debug)] pub struct Mod { /// A span from the first token past `{` to the last token until `}`. /// For `mod foo;`, the inner span ranges from the first token /// to the last token in the external file. pub inner: Span, + /// `unsafe` keyword accepted syntactically for macro DSLs, but not + /// semantically by Rust. + pub unsafety: Unsafe, pub items: Vec>, /// `true` for `mod foo { .. }`; `false` for `mod foo;`. pub inline: bool, @@ -2302,9 +2305,12 @@ pub struct Mod { /// Foreign module declaration. /// -/// E.g., `extern { .. }` or `extern C { .. }`. +/// E.g., `extern { .. }` or `extern "C" { .. }`. #[derive(Clone, Encodable, Decodable, Debug)] pub struct ForeignMod { + /// `unsafe` keyword accepted syntactically for macro DSLs, but not + /// semantically by Rust. + pub unsafety: Unsafe, pub abi: Option, pub items: Vec>, } diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs index 3ef83ef3fc973..3119c5e0a12fa 100644 --- a/compiler/rustc_ast/src/mut_visit.rs +++ b/compiler/rustc_ast/src/mut_visit.rs @@ -490,7 +490,7 @@ pub fn noop_visit_ty(ty: &mut P, vis: &mut T) { } pub fn noop_visit_foreign_mod(foreign_mod: &mut ForeignMod, vis: &mut T) { - let ForeignMod { abi: _, items } = foreign_mod; + let ForeignMod { unsafety: _, abi: _, items } = foreign_mod; items.flat_map_in_place(|item| vis.flat_map_foreign_item(item)); } @@ -970,7 +970,8 @@ pub fn noop_visit_fn_header(header: &mut FnHeader, vis: &mut T) { vis.visit_asyncness(asyncness); } -pub fn noop_visit_mod(Mod { inner, items, inline: _ }: &mut Mod, vis: &mut T) { +pub fn noop_visit_mod(module: &mut Mod, vis: &mut T) { + let Mod { inner, unsafety: _, items, inline: _ } = module; vis.visit_span(inner); items.flat_map_in_place(|item| vis.flat_map_item(item)); } @@ -990,7 +991,7 @@ pub fn noop_visit_crate(krate: &mut Crate, vis: &mut T) { let len = items.len(); if len == 0 { - let module = Mod { inner: span, items: vec![], inline: true }; + let module = Mod { inner: span, unsafety: Unsafe::No, items: vec![], inline: true }; Crate { module, attrs: vec![], span, proc_macros } } else if len == 1 { let Item { attrs, span, kind, .. } = items.into_iter().next().unwrap().into_inner(); diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs index a01dd8c939cf6..998acf4fd10cb 100644 --- a/compiler/rustc_ast_passes/src/ast_validation.rs +++ b/compiler/rustc_ast_passes/src/ast_validation.rs @@ -990,12 +990,15 @@ impl<'a> Visitor<'a> for AstValidator<'a> { self.error_item_without_body(item.span, "function", msg, " { }"); } } - ItemKind::ForeignMod(_) => { + ItemKind::ForeignMod(ForeignMod { unsafety, .. }) => { let old_item = mem::replace(&mut self.extern_mod, Some(item)); self.invalid_visibility( &item.vis, Some("place qualifiers on individual foreign items instead"), ); + if let Unsafe::Yes(span) = unsafety { + self.err_handler().span_err(span, "extern block cannot be declared unsafe"); + } visit::walk_item(self, item); self.extern_mod = old_item; return; // Avoid visiting again. @@ -1029,7 +1032,10 @@ impl<'a> Visitor<'a> for AstValidator<'a> { walk_list!(self, visit_attribute, &item.attrs); return; } - ItemKind::Mod(Mod { inline, .. }) => { + ItemKind::Mod(Mod { inline, unsafety, .. }) => { + if let Unsafe::Yes(span) = unsafety { + self.err_handler().span_err(span, "module cannot be declared unsafe"); + } // Ensure that `path` attributes on modules are recorded as used (cf. issue #35584). if !inline && !self.session.contains_name(&item.attrs, sym::path) { self.check_mod_file_item_asciionly(item.ident); diff --git a/compiler/rustc_ast_pretty/src/pprust.rs b/compiler/rustc_ast_pretty/src/pprust.rs index 9743a00042969..955d1677647ec 100644 --- a/compiler/rustc_ast_pretty/src/pprust.rs +++ b/compiler/rustc_ast_pretty/src/pprust.rs @@ -1139,7 +1139,11 @@ impl<'a> State<'a> { self.print_fn_full(sig, item.ident, gen, &item.vis, def, body, &item.attrs); } ast::ItemKind::Mod(ref _mod) => { - self.head(visibility_qualified(&item.vis, "mod")); + self.head(to_string(|s| { + s.print_visibility(&item.vis); + s.print_unsafety(_mod.unsafety); + s.word("mod"); + })); self.print_ident(item.ident); if _mod.inline || self.is_expanded { @@ -1154,7 +1158,10 @@ impl<'a> State<'a> { } } ast::ItemKind::ForeignMod(ref nmod) => { - self.head("extern"); + self.head(to_string(|s| { + s.print_unsafety(nmod.unsafety); + s.word("extern"); + })); if let Some(abi) = nmod.abi { self.print_literal(&abi.as_lit()); self.nbsp(); diff --git a/compiler/rustc_expand/src/config.rs b/compiler/rustc_expand/src/config.rs index 97608a389035b..dd087ab91509b 100644 --- a/compiler/rustc_expand/src/config.rs +++ b/compiler/rustc_expand/src/config.rs @@ -399,7 +399,7 @@ impl<'a> StripUnconfigured<'a> { } pub fn configure_foreign_mod(&mut self, foreign_mod: &mut ast::ForeignMod) { - let ast::ForeignMod { abi: _, items } = foreign_mod; + let ast::ForeignMod { unsafety: _, abi: _, items } = foreign_mod; items.flat_map_in_place(|item| self.configure(item)); } diff --git a/compiler/rustc_expand/src/expand.rs b/compiler/rustc_expand/src/expand.rs index ca6f7324ca40f..241566a042a0e 100644 --- a/compiler/rustc_expand/src/expand.rs +++ b/compiler/rustc_expand/src/expand.rs @@ -13,7 +13,7 @@ use rustc_ast::token; use rustc_ast::tokenstream::TokenStream; use rustc_ast::visit::{self, AssocCtxt, Visitor}; use rustc_ast::{self as ast, AttrItem, Block, LitKind, NodeId, PatKind, Path}; -use rustc_ast::{ItemKind, MacArgs, MacCallStmt, MacStmtStyle, StmtKind}; +use rustc_ast::{ItemKind, MacArgs, MacCallStmt, MacStmtStyle, StmtKind, Unsafe}; use rustc_ast_pretty::pprust; use rustc_attr::{self as attr, is_builtin_attr, HasAttrs}; use rustc_data_structures::map_in_place::MapInPlace; @@ -370,11 +370,21 @@ impl<'a, 'b> MacroExpander<'a, 'b> { None => { // Resolution failed so we return an empty expansion krate.attrs = vec![]; - krate.module = ast::Mod { inner: orig_mod_span, items: vec![], inline: true }; + krate.module = ast::Mod { + inner: orig_mod_span, + unsafety: Unsafe::No, + items: vec![], + inline: true, + }; } Some(ast::Item { span, kind, .. }) => { krate.attrs = vec![]; - krate.module = ast::Mod { inner: orig_mod_span, items: vec![], inline: true }; + krate.module = ast::Mod { + inner: orig_mod_span, + unsafety: Unsafe::No, + items: vec![], + inline: true, + }; self.cx.span_err( span, &format!( @@ -1441,8 +1451,15 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> { push_directory(&self.cx.sess, ident, &item.attrs, dir) } else { // We have an outline `mod foo;` so we need to parse the file. - let (new_mod, dir) = - parse_external_mod(&self.cx.sess, ident, span, dir, &mut attrs, pushed); + let (new_mod, dir) = parse_external_mod( + &self.cx.sess, + ident, + span, + old_mod.unsafety, + dir, + &mut attrs, + pushed, + ); let krate = ast::Crate { span: new_mod.inner, diff --git a/compiler/rustc_expand/src/module.rs b/compiler/rustc_expand/src/module.rs index fefc0bdeb7cc2..171cb3fa8e6e9 100644 --- a/compiler/rustc_expand/src/module.rs +++ b/compiler/rustc_expand/src/module.rs @@ -1,4 +1,4 @@ -use rustc_ast::{token, Attribute, Mod}; +use rustc_ast::{token, Attribute, Mod, Unsafe}; use rustc_errors::{struct_span_err, PResult}; use rustc_parse::new_parser_from_file; use rustc_session::parse::ParseSess; @@ -42,6 +42,7 @@ crate fn parse_external_mod( sess: &Session, id: Ident, span: Span, // The span to blame on errors. + unsafety: Unsafe, Directory { mut ownership, path }: Directory, attrs: &mut Vec, pop_mod_stack: &mut bool, @@ -60,13 +61,16 @@ crate fn parse_external_mod( drop(included_mod_stack); // Actually parse the external file as a module. - let mut module = - new_parser_from_file(&sess.parse_sess, &mp.path, Some(span)).parse_mod(&token::Eof)?; + let mut parser = new_parser_from_file(&sess.parse_sess, &mp.path, Some(span)); + let mut module = parser.parse_mod(&token::Eof, unsafety)?; module.0.inline = false; module }; // (1) ...instead, we return a dummy module. - let (module, mut new_attrs) = result.map_err(|mut err| err.emit()).unwrap_or_default(); + let (module, mut new_attrs) = result.map_err(|mut err| err.emit()).unwrap_or_else(|_| { + let module = Mod { inner: Span::default(), unsafety, items: Vec::new(), inline: false }; + (module, Vec::new()) + }); attrs.append(&mut new_attrs); // Extract the directory path for submodules of `module`. diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs index 9143af651df2d..1a428f8bb0ab5 100644 --- a/compiler/rustc_parse/src/parser/item.rs +++ b/compiler/rustc_parse/src/parser/item.rs @@ -28,7 +28,7 @@ impl<'a> Parser<'a> { /// Parses a source module as a crate. This is the main entry point for the parser. pub fn parse_crate_mod(&mut self) -> PResult<'a, ast::Crate> { let lo = self.token.span; - let (module, attrs) = self.parse_mod(&token::Eof)?; + let (module, attrs) = self.parse_mod(&token::Eof, Unsafe::No)?; let span = lo.to(self.token.span); let proc_macros = Vec::new(); // Filled in by `proc_macro_harness::inject()`. Ok(ast::Crate { attrs, module, span, proc_macros }) @@ -36,27 +36,38 @@ impl<'a> Parser<'a> { /// Parses a `mod { ... }` or `mod ;` item. fn parse_item_mod(&mut self, attrs: &mut Vec) -> PResult<'a, ItemInfo> { + let unsafety = self.parse_unsafety(); + self.expect_keyword(kw::Mod)?; let id = self.parse_ident()?; let (module, mut inner_attrs) = if self.eat(&token::Semi) { - Default::default() + (Mod { inner: Span::default(), unsafety, items: Vec::new(), inline: false }, Vec::new()) } else { self.expect(&token::OpenDelim(token::Brace))?; - self.parse_mod(&token::CloseDelim(token::Brace))? + self.parse_mod(&token::CloseDelim(token::Brace), unsafety)? }; attrs.append(&mut inner_attrs); Ok((id, ItemKind::Mod(module))) } /// Parses the contents of a module (inner attributes followed by module items). - pub fn parse_mod(&mut self, term: &TokenKind) -> PResult<'a, (Mod, Vec)> { + pub fn parse_mod( + &mut self, + term: &TokenKind, + unsafety: Unsafe, + ) -> PResult<'a, (Mod, Vec)> { let lo = self.token.span; let attrs = self.parse_inner_attributes()?; - let module = self.parse_mod_items(term, lo)?; + let module = self.parse_mod_items(term, lo, unsafety)?; Ok((module, attrs)) } /// Given a termination token, parses all of the items in a module. - fn parse_mod_items(&mut self, term: &TokenKind, inner_lo: Span) -> PResult<'a, Mod> { + fn parse_mod_items( + &mut self, + term: &TokenKind, + inner_lo: Span, + unsafety: Unsafe, + ) -> PResult<'a, Mod> { let mut items = vec![]; while let Some(item) = self.parse_item()? { items.push(item); @@ -75,7 +86,7 @@ impl<'a> Parser<'a> { let hi = if self.token.span.is_dummy() { inner_lo } else { self.prev_token.span }; - Ok(Mod { inner: inner_lo.to(hi), items, inline: true }) + Ok(Mod { inner: inner_lo.to(hi), unsafety, items, inline: true }) } } @@ -235,8 +246,13 @@ impl<'a> Parser<'a> { self.parse_item_extern_crate()? } else { // EXTERN BLOCK - self.parse_item_foreign_mod(attrs)? + self.parse_item_foreign_mod(attrs, Unsafe::No)? } + } else if self.is_unsafe_foreign_mod() { + // EXTERN BLOCK + let unsafety = self.parse_unsafety(); + self.expect_keyword(kw::Extern)?; + self.parse_item_foreign_mod(attrs, unsafety)? } else if self.is_static_global() { // STATIC ITEM self.bump(); // `static` @@ -256,7 +272,9 @@ impl<'a> Parser<'a> { { // IMPL ITEM self.parse_item_impl(attrs, def())? - } else if self.eat_keyword(kw::Mod) { + } else if self.check_keyword(kw::Mod) + || self.check_keyword(kw::Unsafe) && self.is_keyword_ahead(1, &[kw::Mod]) + { // MODULE ITEM self.parse_item_mod(attrs)? } else if self.eat_keyword(kw::Type) { @@ -893,10 +911,14 @@ impl<'a> Parser<'a> { /// extern "C" {} /// extern {} /// ``` - fn parse_item_foreign_mod(&mut self, attrs: &mut Vec) -> PResult<'a, ItemInfo> { + fn parse_item_foreign_mod( + &mut self, + attrs: &mut Vec, + unsafety: Unsafe, + ) -> PResult<'a, ItemInfo> { let abi = self.parse_abi(); // ABI? let items = self.parse_item_list(attrs, |p| p.parse_foreign_item())?; - let module = ast::ForeignMod { abi, items }; + let module = ast::ForeignMod { unsafety, abi, items }; Ok((Ident::invalid(), ItemKind::ForeignMod(module))) } @@ -938,6 +960,15 @@ impl<'a> Parser<'a> { .emit(); } + fn is_unsafe_foreign_mod(&self) -> bool { + self.token.is_keyword(kw::Unsafe) + && self.is_keyword_ahead(1, &[kw::Extern]) + && self.look_ahead( + 2 + self.look_ahead(2, |t| t.can_begin_literal_maybe_minus() as usize), + |t| t.kind == token::OpenDelim(token::Brace), + ) + } + fn is_static_global(&mut self) -> bool { if self.check_keyword(kw::Static) { // Check if this could be a closure. @@ -1552,10 +1583,14 @@ impl<'a> Parser<'a> { // `$qual fn` or `$qual $qual`: || QUALS.iter().any(|&kw| self.check_keyword(kw)) && self.look_ahead(1, |t| { - // ...qualified and then `fn`, e.g. `const fn`. + // `$qual fn`, e.g. `const fn` or `async fn`. t.is_keyword(kw::Fn) - // Two qualifiers. This is enough. Due `async` we need to check that it's reserved. - || t.is_non_raw_ident_where(|i| QUALS.contains(&i.name) && i.is_reserved()) + // Two qualifiers `$qual $qual` is enough, e.g. `async unsafe`. + || t.is_non_raw_ident_where(|i| QUALS.contains(&i.name) + // Rule out 2015 `const async: T = val`. + && i.is_reserved() + // Rule out unsafe extern block. + && !self.is_unsafe_foreign_mod()) }) // `extern ABI fn` || self.check_keyword(kw::Extern) @@ -1567,9 +1602,9 @@ impl<'a> Parser<'a> { /// up to and including the `fn` keyword. The formal grammar is: /// /// ``` - /// Extern = "extern" StringLit ; + /// Extern = "extern" StringLit? ; /// FnQual = "const"? "async"? "unsafe"? Extern? ; - /// FnFrontMatter = FnQual? "fn" ; + /// FnFrontMatter = FnQual "fn" ; /// ``` pub(super) fn parse_fn_front_matter(&mut self) -> PResult<'a, FnHeader> { let constness = self.parse_constness(); diff --git a/src/test/ui/ast-json/ast-json-noexpand-output.stdout b/src/test/ui/ast-json/ast-json-noexpand-output.stdout index 031c0d0cae51c..0e5a3a14ac7b5 100644 --- a/src/test/ui/ast-json/ast-json-noexpand-output.stdout +++ b/src/test/ui/ast-json/ast-json-noexpand-output.stdout @@ -1 +1 @@ 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+{"module":{"inner":{"lo":0,"hi":0},"unsafety":"No","items":[{"attrs":[],"id":0,"span":{"lo":0,"hi":0},"vis":{"node":"Inherited","span":{"lo":0,"hi":0}},"ident":{"name":"core","span":{"lo":0,"hi":0}},"kind":{"variant":"ExternCrate","fields":[null]},"tokens":null}],"inline":true},"attrs":[{"kind":{"variant":"Normal","fields":[{"path":{"span":{"lo":0,"hi":0},"segments":[{"ident":{"name":"crate_type","span":{"lo":0,"hi":0}},"id":0,"args":null}]},"args":{"variant":"Eq","fields":[{"lo":0,"hi":0},{"0":[[{"variant":"Token","fields":[{"kind":{"variant":"Literal","fields":[{"kind":"Str","symbol":"lib","suffix":null}]},"span":{"lo":0,"hi":0}}]},"Alone"]]}]}}]},"id":null,"style":"Inner","span":{"lo":0,"hi":0}}],"span":{"lo":0,"hi":0},"proc_macros":[]} diff --git a/src/test/ui/ast-json/ast-json-output.stdout b/src/test/ui/ast-json/ast-json-output.stdout index 9b3b6870cbe7e..8752ed2ae9993 100644 --- a/src/test/ui/ast-json/ast-json-output.stdout +++ b/src/test/ui/ast-json/ast-json-output.stdout @@ 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diff --git a/src/test/ui/parser/unsafe-foreign-mod.rs b/src/test/ui/parser/unsafe-foreign-mod.rs new file mode 100644 index 0000000000000..872af95bd225b --- /dev/null +++ b/src/test/ui/parser/unsafe-foreign-mod.rs @@ -0,0 +1,9 @@ +unsafe extern { + //~^ ERROR extern block cannot be declared unsafe +} + +unsafe extern "C" { + //~^ ERROR extern block cannot be declared unsafe +} + +fn main() {} diff --git a/src/test/ui/parser/unsafe-foreign-mod.stderr b/src/test/ui/parser/unsafe-foreign-mod.stderr new file mode 100644 index 0000000000000..5e10988051ea0 --- /dev/null +++ b/src/test/ui/parser/unsafe-foreign-mod.stderr @@ -0,0 +1,14 @@ +error: extern block cannot be declared unsafe + --> $DIR/unsafe-foreign-mod.rs:1:1 + | +LL | unsafe extern { + | ^^^^^^ + +error: extern block cannot be declared unsafe + --> $DIR/unsafe-foreign-mod.rs:5:1 + | +LL | unsafe extern "C" { + | ^^^^^^ + +error: aborting due to 2 previous errors + diff --git a/src/test/ui/parser/unsafe-mod.rs b/src/test/ui/parser/unsafe-mod.rs new file mode 100644 index 0000000000000..7916d878ea585 --- /dev/null +++ b/src/test/ui/parser/unsafe-mod.rs @@ -0,0 +1,9 @@ +unsafe mod m { + //~^ ERROR module cannot be declared unsafe +} + +unsafe mod n; +//~^ ERROR module cannot be declared unsafe +//~^^ ERROR file not found for module `n` + +fn main() {} diff --git a/src/test/ui/parser/unsafe-mod.stderr b/src/test/ui/parser/unsafe-mod.stderr new file mode 100644 index 0000000000000..259b2c1d61e08 --- /dev/null +++ b/src/test/ui/parser/unsafe-mod.stderr @@ -0,0 +1,23 @@ +error[E0583]: file not found for module `n` + --> $DIR/unsafe-mod.rs:5:1 + | +LL | unsafe mod n; + | ^^^^^^^^^^^^^ + | + = help: to create the module `n`, create file "$DIR/n.rs" + +error: module cannot be declared unsafe + --> $DIR/unsafe-mod.rs:1:1 + | +LL | unsafe mod m { + | ^^^^^^ + +error: module cannot be declared unsafe + --> $DIR/unsafe-mod.rs:5:1 + | +LL | unsafe mod n; + | ^^^^^^ + +error: aborting due to 3 previous errors + +For more information about this error, try `rustc --explain E0583`. diff --git a/src/test/ui/proc-macro/auxiliary/macro-only-syntax.rs b/src/test/ui/proc-macro/auxiliary/macro-only-syntax.rs new file mode 100644 index 0000000000000..c72306c3d50b3 --- /dev/null +++ b/src/test/ui/proc-macro/auxiliary/macro-only-syntax.rs @@ -0,0 +1,89 @@ +// force-host +// no-prefer-dynamic + +// These are tests for syntax that is accepted by the Rust parser but +// unconditionally rejected semantically after macro expansion. Attribute macros +// are permitted to accept such syntax as long as they replace it with something +// that makes sense to Rust. +// +// We also inspect some of the spans to verify the syntax is not triggering the +// lossy string reparse hack (https://github.com/rust-lang/rust/issues/43081). + +#![crate_type = "proc-macro"] +#![feature(proc_macro_span)] + +extern crate proc_macro; +use proc_macro::{token_stream, Delimiter, TokenStream, TokenTree}; +use std::path::Component; + +// unsafe mod m { +// pub unsafe mod inner; +// } +#[proc_macro_attribute] +pub fn expect_unsafe_mod(_attrs: TokenStream, input: TokenStream) -> TokenStream { + let tokens = &mut input.into_iter(); + expect(tokens, "unsafe"); + expect(tokens, "mod"); + expect(tokens, "m"); + let tokens = &mut expect_brace(tokens); + expect(tokens, "pub"); + expect(tokens, "unsafe"); + expect(tokens, "mod"); + let ident = expect(tokens, "inner"); + expect(tokens, ";"); + check_useful_span(ident, "unsafe-mod.rs"); + TokenStream::new() +} + +// unsafe extern { +// type T; +// } +#[proc_macro_attribute] +pub fn expect_unsafe_foreign_mod(_attrs: TokenStream, input: TokenStream) -> TokenStream { + let tokens = &mut input.into_iter(); + expect(tokens, "unsafe"); + expect(tokens, "extern"); + let tokens = &mut expect_brace(tokens); + expect(tokens, "type"); + let ident = expect(tokens, "T"); + expect(tokens, ";"); + check_useful_span(ident, "unsafe-foreign-mod.rs"); + TokenStream::new() +} + +// unsafe extern "C++" {} +#[proc_macro_attribute] +pub fn expect_unsafe_extern_cpp_mod(_attrs: TokenStream, input: TokenStream) -> TokenStream { + let tokens = &mut input.into_iter(); + expect(tokens, "unsafe"); + expect(tokens, "extern"); + let abi = expect(tokens, "\"C++\""); + expect_brace(tokens); + check_useful_span(abi, "unsafe-foreign-mod.rs"); + TokenStream::new() +} + +fn expect(tokens: &mut token_stream::IntoIter, expected: &str) -> TokenTree { + match tokens.next() { + Some(token) if token.to_string() == expected => token, + wrong => panic!("unexpected token: {:?}, expected `{}`", wrong, expected), + } +} + +fn expect_brace(tokens: &mut token_stream::IntoIter) -> token_stream::IntoIter { + match tokens.next() { + Some(TokenTree::Group(group)) if group.delimiter() == Delimiter::Brace => { + group.stream().into_iter() + } + wrong => panic!("unexpected token: {:?}, expected `{{`", wrong), + } +} + +fn check_useful_span(token: TokenTree, expected_filename: &str) { + let span = token.span(); + assert!(span.start().column < span.end().column); + + let source_path = span.source_file().path(); + let filename = source_path.components().last().unwrap(); + assert_eq!(filename, Component::Normal(expected_filename.as_ref())); +} diff --git a/src/test/ui/proc-macro/unsafe-foreign-mod.rs b/src/test/ui/proc-macro/unsafe-foreign-mod.rs new file mode 100644 index 0000000000000..7bdfa93c21fc7 --- /dev/null +++ b/src/test/ui/proc-macro/unsafe-foreign-mod.rs @@ -0,0 +1,14 @@ +// run-pass +// aux-build:macro-only-syntax.rs + +extern crate macro_only_syntax; + +#[macro_only_syntax::expect_unsafe_foreign_mod] +unsafe extern { + type T; +} + +#[macro_only_syntax::expect_unsafe_extern_cpp_mod] +unsafe extern "C++" {} + +fn main() {} diff --git a/src/test/ui/proc-macro/unsafe-mod.rs b/src/test/ui/proc-macro/unsafe-mod.rs new file mode 100644 index 0000000000000..8ff6e352c53d0 --- /dev/null +++ b/src/test/ui/proc-macro/unsafe-mod.rs @@ -0,0 +1,13 @@ +// run-pass +// aux-build:macro-only-syntax.rs + +#![feature(proc_macro_hygiene)] + +extern crate macro_only_syntax; + +#[macro_only_syntax::expect_unsafe_mod] +unsafe mod m { + pub unsafe mod inner; +} + +fn main() {}