Move standard library injection into libsyntax_ext

4 files changed, 5 insertions, 116 deletions

diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 17f379f31b2..bb6a8dfb141 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -153,7 +153,6 @@ pub mod mut_visit;
 pub mod parse;
 pub mod ptr;
 pub mod show_span;
-pub mod std_inject;
 pub use syntax_pos::edition;
 pub use syntax_pos::symbol;
 pub mod tokenstream;
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index 225065c1cf1..1aac8bbb7aa 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -10,9 +10,10 @@ use crate::parse::token::TokenKind;
 use crate::tokenstream::{TokenStream, TokenTree};
 use crate::diagnostics::plugin::ErrorMap;
 use crate::print::pprust;
+use crate::symbol::Symbol;
 
 use errors::{Applicability, FatalError, Level, Handler, ColorConfig, Diagnostic, DiagnosticBuilder};
-use rustc_data_structures::sync::{Lrc, Lock};
+use rustc_data_structures::sync::{Lrc, Lock, Once};
 use syntax_pos::{Span, SourceFile, FileName, MultiSpan};
 use syntax_pos::edition::Edition;
 
@@ -58,6 +59,7 @@ pub struct ParseSess {
     pub let_chains_spans: Lock<Vec<Span>>,
     // Places where `async || ..` exprs were used and should be feature gated.
     pub async_closure_spans: Lock<Vec<Span>>,
+    pub injected_crate_name: Once<Symbol>,
 }
 
 impl ParseSess {
@@ -86,6 +88,7 @@ impl ParseSess {
             param_attr_spans: Lock::new(Vec::new()),
             let_chains_spans: Lock::new(Vec::new()),
             async_closure_spans: Lock::new(Vec::new()),
+            injected_crate_name: Once::new(),
         }
     }
 
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 16e0bace925..c4623576395 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -10,7 +10,6 @@ use crate::parse::{self, ParseSess};
 use crate::print::pp::{self, Breaks};
 use crate::print::pp::Breaks::{Consistent, Inconsistent};
 use crate::ptr::P;
-use crate::std_inject;
 use crate::symbol::{kw, sym};
 use crate::tokenstream::{self, TokenStream, TokenTree};
 
@@ -114,7 +113,7 @@ pub fn print_crate<'a>(cm: &'a SourceMap,
         is_expanded,
     };
 
-    if is_expanded && std_inject::injected_crate_name().is_some() {
+    if is_expanded && sess.injected_crate_name.try_get().is_some() {
         // We need to print `#![no_std]` (and its feature gate) so that
         // compiling pretty-printed source won't inject libstd again.
         // However we don't want these attributes in the AST because
diff --git a/src/libsyntax/std_inject.rs b/src/libsyntax/std_inject.rs
deleted file mode 100644
index 3fba81c0b69..00000000000
--- a/src/libsyntax/std_inject.rs
+++ /dev/null
@@ -1,112 +0,0 @@
-use crate::ast;
-use crate::attr;
-use crate::edition::Edition;
-use crate::ext::hygiene::{ExpnId, MacroKind};
-use crate::symbol::{Ident, Symbol, kw, sym};
-use crate::source_map::{ExpnInfo, ExpnKind, dummy_spanned, respan};
-use crate::ptr::P;
-use crate::tokenstream::TokenStream;
-
-use std::cell::Cell;
-use std::iter;
-use syntax_pos::DUMMY_SP;
-
-pub fn injected_crate_name() -> Option<&'static str> {
-    INJECTED_CRATE_NAME.with(|name| name.get())
-}
-
-thread_local! {
-    // A `Symbol` might make more sense here, but it doesn't work, probably for
-    // reasons relating to the use of thread-local storage for the Symbol
-    // interner.
-    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<&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, sym::no_core) {
-        return krate;
-    } else if attr::contains_name(&krate.attrs, sym::no_std) {
-        if attr::contains_name(&krate.attrs, sym::compiler_builtins) {
-            &["core"]
-        } else {
-            &["core", "compiler_builtins"]
-        }
-    } else {
-        &["std"]
-    };
-
-    // .rev() to preserve ordering above in combination with insert(0, ...)
-    let alt_std_name = alt_std_name.map(Symbol::intern);
-    for orig_name_str in names.iter().rev() {
-        // HACK(eddyb) gensym the injected crates on the Rust 2018 edition,
-        // so they don't accidentally interfere with the new import paths.
-        let orig_name_sym = Symbol::intern(orig_name_str);
-        let orig_name_ident = Ident::with_empty_ctxt(orig_name_sym);
-        let (rename, orig_name) = if rust_2018 {
-            (orig_name_ident.gensym(), Some(orig_name_sym))
-        } else {
-            (orig_name_ident, 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::with_empty_ctxt(sym::macro_use))
-            )],
-            vis: dummy_spanned(ast::VisibilityKind::Inherited),
-            node: ast::ItemKind::ExternCrate(alt_std_name.or(orig_name)),
-            ident: rename,
-            id: ast::DUMMY_NODE_ID,
-            span: DUMMY_SP,
-            tokens: None,
-        }));
-    }
-
-    // the crates have been injected, the assumption is that the first one is the one with
-    // the prelude.
-    let name = names[0];
-
-    INJECTED_CRATE_NAME.with(|opt_name| opt_name.set(Some(name)));
-
-    let span = DUMMY_SP.fresh_expansion(ExpnId::root(), ExpnInfo::allow_unstable(
-        ExpnKind::Macro(MacroKind::Attr, sym::std_inject), DUMMY_SP, edition,
-        [sym::prelude_import][..].into(),
-    ));
-
-    krate.module.items.insert(0, P(ast::Item {
-        attrs: vec![ast::Attribute {
-            style: ast::AttrStyle::Outer,
-            path: ast::Path::from_ident(ast::Ident::new(sym::prelude_import, span)),
-            tokens: TokenStream::empty(),
-            id: attr::mk_attr_id(),
-            is_sugared_doc: false,
-            span,
-        }],
-        vis: respan(span.shrink_to_lo(), ast::VisibilityKind::Inherited),
-        node: ast::ItemKind::Use(P(ast::UseTree {
-            prefix: ast::Path {
-                segments: iter::once(ast::Ident::with_empty_ctxt(kw::PathRoot))
-                    .chain(
-                        [name, "prelude", "v1"].iter().cloned()
-                            .map(ast::Ident::from_str)
-                    ).map(ast::PathSegment::from_ident).collect(),
-                span,
-            },
-            kind: ast::UseTreeKind::Glob,
-            span,
-        })),
-        id: ast::DUMMY_NODE_ID,
-        ident: ast::Ident::invalid(),
-        span,
-        tokens: None,
-    }));
-
-    krate
-}