diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs index 127331152c155..26c0ede48b7b4 100644 --- a/src/librustc_resolve/lib.rs +++ b/src/librustc_resolve/lib.rs @@ -1407,6 +1407,7 @@ pub struct Resolver<'a> { graph_root: Module<'a>, prelude: Option>, + extern_prelude: FxHashSet, /// n.b. This is used only for better diagnostics, not name resolution itself. has_self: FxHashSet, @@ -1715,6 +1716,7 @@ impl<'a> Resolver<'a> { // AST. graph_root, prelude: None, + extern_prelude: session.opts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect(), has_self: FxHashSet(), field_names: FxHashMap(), @@ -1970,13 +1972,32 @@ impl<'a> Resolver<'a> { } } - match self.prelude { - Some(prelude) if !module.no_implicit_prelude => { - self.resolve_ident_in_module_unadjusted(prelude, ident, ns, false, false, path_span) - .ok().map(LexicalScopeBinding::Item) + if !module.no_implicit_prelude { + // `record_used` means that we don't try to load crates during speculative resolution + if record_used && ns == TypeNS && self.extern_prelude.contains(&ident.name) { + if !self.session.features_untracked().extern_prelude { + feature_err(&self.session.parse_sess, "extern_prelude", + ident.span, GateIssue::Language, + "access to extern crates through prelude is experimental").emit(); + } + + let crate_id = self.crate_loader.process_path_extern(ident.name, ident.span); + let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX }); + self.populate_module_if_necessary(crate_root); + + let binding = (crate_root, ty::Visibility::Public, + ident.span, Mark::root()).to_name_binding(self.arenas); + return Some(LexicalScopeBinding::Item(binding)); + } + if let Some(prelude) = self.prelude { + if let Ok(binding) = self.resolve_ident_in_module_unadjusted(prelude, ident, ns, + false, false, path_span) { + return Some(LexicalScopeBinding::Item(binding)); + } } - _ => None, } + + None } fn hygienic_lexical_parent(&mut self, mut module: Module<'a>, span: &mut Span) @@ -3587,8 +3608,9 @@ impl<'a> Resolver<'a> { // We can see through blocks } else { // Items from the prelude - if let Some(prelude) = self.prelude { - if !module.no_implicit_prelude { + if !module.no_implicit_prelude { + names.extend(self.extern_prelude.iter().cloned()); + if let Some(prelude) = self.prelude { add_module_candidates(prelude, &mut names); } } diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs index f16b1ba440ac4..0fb8fe2ad6319 100644 --- a/src/libsyntax/feature_gate.rs +++ b/src/libsyntax/feature_gate.rs @@ -391,7 +391,7 @@ declare_features! ( (active, generic_associated_types, "1.23.0", Some(44265), None), // Resolve absolute paths as paths from other crates - (active, extern_absolute_paths, "1.24.0", Some(44660), None), + (active, extern_absolute_paths, "1.24.0", Some(44660), Some(Edition::Edition2018)), // `foo.rs` as an alternative to `foo/mod.rs` (active, non_modrs_mods, "1.24.0", Some(44660), Some(Edition::Edition2018)), @@ -460,6 +460,9 @@ declare_features! ( // #[doc(alias = "...")] (active, doc_alias, "1.27.0", Some(50146), None), + + // Access to crate names passed via `--extern` through prelude + (active, extern_prelude, "1.27.0", Some(44660), Some(Edition::Edition2018)), ); declare_features! ( diff --git a/src/test/run-make-fulldeps/extern-prelude/Makefile b/src/test/run-make-fulldeps/extern-prelude/Makefile new file mode 100644 index 0000000000000..aa8158c6eb381 --- /dev/null +++ b/src/test/run-make-fulldeps/extern-prelude/Makefile @@ -0,0 +1,12 @@ +-include ../tools.mk + +all: + $(RUSTC) ep-lib.rs + $(RUSTC) ep-vec.rs + + $(RUSTC) basic.rs --extern ep_lib=$(TMPDIR)/libep_lib.rlib + $(RUSTC) shadow-mod.rs --extern ep_lib=$(TMPDIR)/libep_lib.rlib + $(RUSTC) shadow-prelude.rs --extern Vec=$(TMPDIR)/libep_vec.rlib + $(RUSTC) feature-gate.rs --extern ep_lib=$(TMPDIR)/libep_lib.rlib 2>&1 | $(CGREP) "access to extern crates through prelude is experimental" + $(RUSTC) relative-only.rs --extern ep_lib=$(TMPDIR)/libep_lib.rlib 2>&1 | $(CGREP) "unresolved import" + $(RUSTC) relative-only.rs --extern ep_lib=$(TMPDIR)/libep_lib.rlib 2>&1 | $(CGREP) "failed to resolve" diff --git a/src/test/run-make-fulldeps/extern-prelude/basic.rs b/src/test/run-make-fulldeps/extern-prelude/basic.rs new file mode 100644 index 0000000000000..b8d6a772e2a98 --- /dev/null +++ b/src/test/run-make-fulldeps/extern-prelude/basic.rs @@ -0,0 +1,16 @@ +// Copyright 2018 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. + +#![feature(extern_prelude)] + +fn main() { + let s = ep_lib::S; // It works + s.external(); +} diff --git a/src/test/run-make-fulldeps/extern-prelude/ep-lib.rs b/src/test/run-make-fulldeps/extern-prelude/ep-lib.rs new file mode 100644 index 0000000000000..dac0a3ce760fa --- /dev/null +++ b/src/test/run-make-fulldeps/extern-prelude/ep-lib.rs @@ -0,0 +1,17 @@ +// Copyright 2017 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. + +#![crate_type = "rlib"] + +pub struct S; + +impl S { + pub fn external(&self) {} +} diff --git a/src/test/run-make-fulldeps/extern-prelude/ep-vec.rs b/src/test/run-make-fulldeps/extern-prelude/ep-vec.rs new file mode 100644 index 0000000000000..f750a26f9e6ff --- /dev/null +++ b/src/test/run-make-fulldeps/extern-prelude/ep-vec.rs @@ -0,0 +1,13 @@ +// Copyright 2017 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. + +#![crate_type = "rlib"] + +pub fn new(arg1: f32, arg2: ()) {} diff --git a/src/test/run-make-fulldeps/extern-prelude/feature-gate.rs b/src/test/run-make-fulldeps/extern-prelude/feature-gate.rs new file mode 100644 index 0000000000000..49763f3ba6a23 --- /dev/null +++ b/src/test/run-make-fulldeps/extern-prelude/feature-gate.rs @@ -0,0 +1,13 @@ +// Copyright 2018 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. + +fn main() { + let s = ep_lib::S; // Feature error +} diff --git a/src/test/run-make-fulldeps/extern-prelude/relative-only.rs b/src/test/run-make-fulldeps/extern-prelude/relative-only.rs new file mode 100644 index 0000000000000..0cd56b93de6a0 --- /dev/null +++ b/src/test/run-make-fulldeps/extern-prelude/relative-only.rs @@ -0,0 +1,19 @@ +// Copyright 2018 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. + +// Extern prelude names are not available by absolute paths + +#![feature(extern_prelude)] + +use ep_lib::S; + +fn main() { + let s = ::ep_lib::S; +} diff --git a/src/test/run-make-fulldeps/extern-prelude/shadow-mod.rs b/src/test/run-make-fulldeps/extern-prelude/shadow-mod.rs new file mode 100644 index 0000000000000..52213c8d4f950 --- /dev/null +++ b/src/test/run-make-fulldeps/extern-prelude/shadow-mod.rs @@ -0,0 +1,24 @@ +// Copyright 2018 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. + +// Local module shadows `ep_lib` from extern prelude + +mod ep_lib { + pub struct S; + + impl S { + pub fn internal(&self) {} + } +} + +fn main() { + let s = ep_lib::S; + s.internal(); // OK +} diff --git a/src/test/run-make-fulldeps/extern-prelude/shadow-prelude.rs b/src/test/run-make-fulldeps/extern-prelude/shadow-prelude.rs new file mode 100644 index 0000000000000..de1c4d16d39bb --- /dev/null +++ b/src/test/run-make-fulldeps/extern-prelude/shadow-prelude.rs @@ -0,0 +1,17 @@ +// Copyright 2018 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. + +// Extern prelude shadows standard library prelude + +#![feature(extern_prelude)] + +fn main() { + let x = Vec::new(0f32, ()); // OK +} diff --git a/src/test/run-pass/extern-prelude-no-speculative.rs b/src/test/run-pass/extern-prelude-no-speculative.rs new file mode 100644 index 0000000000000..ff3aec439aae0 --- /dev/null +++ b/src/test/run-pass/extern-prelude-no-speculative.rs @@ -0,0 +1,21 @@ +// Copyright 2014 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. + +// compile-flags: --extern LooksLikeExternCrate=/path/to/nowhere + +mod m { + pub struct LooksLikeExternCrate; +} + +fn main() { + // OK, speculative resolution for `unused_qualifications` doesn't try + // to resolve this as an extern crate and load that crate + let s = m::LooksLikeExternCrate {}; +} diff --git a/src/test/ui/feature-gate-extern_prelude.rs b/src/test/ui/feature-gate-extern_prelude.rs new file mode 100644 index 0000000000000..8d3a30305bdb0 --- /dev/null +++ b/src/test/ui/feature-gate-extern_prelude.rs @@ -0,0 +1,11 @@ +// Copyright 2018 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. + +can-only-test-this-in-run-make-fulldeps //~ ERROR expected one of `!` or `::`, found `-` diff --git a/src/test/ui/feature-gate-extern_prelude.stderr b/src/test/ui/feature-gate-extern_prelude.stderr new file mode 100644 index 0000000000000..5abf369baf9c0 --- /dev/null +++ b/src/test/ui/feature-gate-extern_prelude.stderr @@ -0,0 +1,8 @@ +error: expected one of `!` or `::`, found `-` + --> $DIR/feature-gate-extern_prelude.rs:11:4 + | +LL | can-only-test-this-in-run-make-fulldeps //~ ERROR expected one of `!` or `::`, found `-` + | ^ expected one of `!` or `::` here + +error: aborting due to previous error +