Merge branch 'master' into feature/core_convert_id

1 files changed, 62 insertions, 29 deletions

diff --git a/src/libsyntax/std_inject.rs b/src/libsyntax/std_inject.rs
index 00546400bb5..626a610017d 100644
--- a/src/libsyntax/std_inject.rs
+++ b/src/libsyntax/std_inject.rs
@@ -11,10 +11,12 @@
 use ast;
 use attr;
 use std::cell::Cell;
+use std::iter;
+use edition::Edition;
 use ext::hygiene::{Mark, SyntaxContext};
 use symbol::{Symbol, keywords};
 use syntax_pos::{DUMMY_SP, Span};
-use codemap::{ExpnInfo, NameAndSpan, MacroAttribute};
+use codemap::{ExpnInfo, MacroAttribute, dummy_spanned, hygiene, respan};
 use ptr::P;
 use tokenstream::TokenStream;
 
@@ -25,12 +27,12 @@ fn ignored_span(sp: Span) -> Span {
     let mark = Mark::fresh(Mark::root());
     mark.set_expn_info(ExpnInfo {
         call_site: DUMMY_SP,
-        callee: NameAndSpan {
-            format: MacroAttribute(Symbol::intern("std_inject")),
-            span: None,
-            allow_internal_unstable: true,
-            allow_internal_unsafe: false,
-        }
+        def_site: None,
+        format: MacroAttribute(Symbol::intern("std_inject")),
+        allow_internal_unstable: true,
+        allow_internal_unsafe: false,
+        local_inner_macros: false,
+        edition: hygiene::default_edition(),
     });
     sp.with_ctxt(SyntaxContext::empty().apply_mark(mark))
 }
@@ -43,47 +45,78 @@ thread_local! {
     static INJECTED_CRATE_NAME: Cell<Option<&'static str>> = Cell::new(None);
 }
 
-pub fn maybe_inject_crates_ref(mut krate: ast::Crate, alt_std_name: Option<String>) -> ast::Crate {
-    let name = if attr::contains_name(&krate.attrs, "no_core") {
+pub fn maybe_inject_crates_ref(
+    mut krate: ast::Crate,
+    alt_std_name: Option<&str>,
+    edition: Edition,
+) -> ast::Crate {
+    let rust_2018 = edition >= Edition::Edition2018;
+
+    // the first name in this list is the crate name of the crate with the prelude
+    let names: &[&str] = if attr::contains_name(&krate.attrs, "no_core") {
         return krate;
     } else if attr::contains_name(&krate.attrs, "no_std") {
-        "core"
+        if attr::contains_name(&krate.attrs, "compiler_builtins") {
+            &["core"]
+        } else {
+            &["core", "compiler_builtins"]
+        }
     } else {
-        "std"
+        &["std"]
     };
 
-    INJECTED_CRATE_NAME.with(|opt_name| opt_name.set(Some(name)));
+    // .rev() to preserve ordering above in combination with insert(0, ...)
+    let alt_std_name = alt_std_name.map(Symbol::intern);
+    for orig_name in names.iter().rev() {
+        let orig_name = Symbol::intern(orig_name);
+        let mut rename = orig_name;
+        // HACK(eddyb) gensym the injected crates on the Rust 2018 edition,
+        // so they don't accidentally interfere with the new import paths.
+        if rust_2018 {
+            rename = orig_name.gensymed();
+        }
+        let orig_name = if rename != orig_name {
+            Some(orig_name)
+        } else {
+            None
+        };
+        krate.module.items.insert(0, P(ast::Item {
+            attrs: vec![attr::mk_attr_outer(DUMMY_SP,
+                                            attr::mk_attr_id(),
+                                            attr::mk_word_item(ast::Ident::from_str("macro_use")))],
+            vis: dummy_spanned(ast::VisibilityKind::Inherited),
+            node: ast::ItemKind::ExternCrate(alt_std_name.or(orig_name)),
+            ident: ast::Ident::with_empty_ctxt(rename),
+            id: ast::DUMMY_NODE_ID,
+            span: DUMMY_SP,
+            tokens: None,
+        }));
+    }
 
-    let crate_name = Symbol::intern(&alt_std_name.unwrap_or_else(|| name.to_string()));
+    // the crates have been injected, the assumption is that the first one is the one with
+    // the prelude.
+    let name = names[0];
 
-    krate.module.items.insert(0, P(ast::Item {
-        attrs: vec![attr::mk_attr_outer(DUMMY_SP,
-                                        attr::mk_attr_id(),
-                                        attr::mk_word_item(Symbol::intern("macro_use")))],
-        vis: ast::Visibility::Inherited,
-        node: ast::ItemKind::ExternCrate(Some(crate_name)),
-        ident: ast::Ident::from_str(name),
-        id: ast::DUMMY_NODE_ID,
-        span: DUMMY_SP,
-        tokens: None,
-    }));
+    INJECTED_CRATE_NAME.with(|opt_name| opt_name.set(Some(name)));
 
     let span = ignored_span(DUMMY_SP);
     krate.module.items.insert(0, P(ast::Item {
         attrs: vec![ast::Attribute {
             style: ast::AttrStyle::Outer,
-            path: ast::Path::from_ident(span, ast::Ident::from_str("prelude_import")),
+            path: ast::Path::from_ident(ast::Ident::new(Symbol::intern("prelude_import"), span)),
             tokens: TokenStream::empty(),
             id: attr::mk_attr_id(),
             is_sugared_doc: false,
             span,
         }],
-        vis: ast::Visibility::Inherited,
+        vis: respan(span.shrink_to_lo(), ast::VisibilityKind::Inherited),
         node: ast::ItemKind::Use(P(ast::UseTree {
             prefix: ast::Path {
-                segments: ["{{root}}", name, "prelude", "v1"].into_iter().map(|name| {
-                    ast::PathSegment::from_ident(ast::Ident::from_str(name), DUMMY_SP)
-                }).collect(),
+                segments: iter::once(keywords::CrateRoot.ident())
+                    .chain(
+                        [name, "prelude", "v1"].iter().cloned()
+                            .map(ast::Ident::from_str)
+                    ).map(ast::PathSegment::from_ident).collect(),
                 span,
             },
             kind: ast::UseTreeKind::Glob,