Auto merge of #49390 - Zoxc:sync-syntax, r=michaelwoerister

More thread-safety changes

r? @michaelwoerister

3 files changed, 18 insertions, 29 deletions

diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index 152c4c31eb3..39b2f77f230 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -1781,7 +1781,6 @@ mod tests {
     use errors;
     use feature_gate::UnstableFeatures;
     use parse::token;
-    use std::cell::RefCell;
     use std::collections::HashSet;
     use std::io;
     use std::path::PathBuf;
@@ -1797,12 +1796,12 @@ mod tests {
             span_diagnostic: errors::Handler::with_emitter(true, false, Box::new(emitter)),
             unstable_features: UnstableFeatures::from_environment(),
             config: CrateConfig::new(),
-            included_mod_stack: RefCell::new(Vec::new()),
+            included_mod_stack: Lock::new(Vec::new()),
             code_map: cm,
-            missing_fragment_specifiers: RefCell::new(HashSet::new()),
-            raw_identifier_spans: RefCell::new(Vec::new()),
+            missing_fragment_specifiers: Lock::new(HashSet::new()),
+            raw_identifier_spans: Lock::new(Vec::new()),
             registered_diagnostics: Lock::new(ErrorMap::new()),
-            non_modrs_mods: RefCell::new(vec![]),
+            non_modrs_mods: Lock::new(vec![]),
         }
     }
 
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index 428b3b136df..ff63c9a5c6d 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -23,7 +23,6 @@ use symbol::Symbol;
 use tokenstream::{TokenStream, TokenTree};
 use diagnostics::plugin::ErrorMap;
 
-use std::cell::RefCell;
 use std::collections::HashSet;
 use std::iter;
 use std::path::{Path, PathBuf};
@@ -46,17 +45,17 @@ pub struct ParseSess {
     pub span_diagnostic: Handler,
     pub unstable_features: UnstableFeatures,
     pub config: CrateConfig,
-    pub missing_fragment_specifiers: RefCell<HashSet<Span>>,
+    pub missing_fragment_specifiers: Lock<HashSet<Span>>,
     /// Places where raw identifiers were used. This is used for feature gating
     /// raw identifiers
-    pub raw_identifier_spans: RefCell<Vec<Span>>,
+    pub raw_identifier_spans: Lock<Vec<Span>>,
     /// The registered diagnostics codes
     pub registered_diagnostics: Lock<ErrorMap>,
     // Spans where a `mod foo;` statement was included in a non-mod.rs file.
     // These are used to issue errors if the non_modrs_mods feature is not enabled.
-    pub non_modrs_mods: RefCell<Vec<(ast::Ident, Span)>>,
+    pub non_modrs_mods: Lock<Vec<(ast::Ident, Span)>>,
     /// Used to determine and report recursive mod inclusions
-    included_mod_stack: RefCell<Vec<PathBuf>>,
+    included_mod_stack: Lock<Vec<PathBuf>>,
     code_map: Lrc<CodeMap>,
 }
 
@@ -75,12 +74,12 @@ impl ParseSess {
             span_diagnostic: handler,
             unstable_features: UnstableFeatures::from_environment(),
             config: HashSet::new(),
-            missing_fragment_specifiers: RefCell::new(HashSet::new()),
-            raw_identifier_spans: RefCell::new(Vec::new()),
+            missing_fragment_specifiers: Lock::new(HashSet::new()),
+            raw_identifier_spans: Lock::new(Vec::new()),
             registered_diagnostics: Lock::new(ErrorMap::new()),
-            included_mod_stack: RefCell::new(vec![]),
+            included_mod_stack: Lock::new(vec![]),
             code_map,
-            non_modrs_mods: RefCell::new(vec![]),
+            non_modrs_mods: Lock::new(vec![]),
         }
     }
 
diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index df0ea05005c..8da79f92768 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -25,9 +25,8 @@ use syntax_pos::{self, Span, FileName};
 use tokenstream::{TokenStream, TokenTree};
 use tokenstream;
 
-use std::cell::Cell;
 use std::{cmp, fmt};
-use rustc_data_structures::sync::Lrc;
+use rustc_data_structures::sync::{Lrc, Lock};
 
 #[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Hash, Debug, Copy)]
 pub enum BinOpToken {
@@ -627,15 +626,8 @@ pub fn is_op(tok: &Token) -> bool {
     }
 }
 
-pub struct LazyTokenStream(Cell<Option<TokenStream>>);
-
-impl Clone for LazyTokenStream {
-    fn clone(&self) -> Self {
-        let opt_stream = self.0.take();
-        self.0.set(opt_stream.clone());
-        LazyTokenStream(Cell::new(opt_stream))
-    }
-}
+#[derive(Clone)]
+pub struct LazyTokenStream(Lock<Option<TokenStream>>);
 
 impl cmp::Eq for LazyTokenStream {}
 impl PartialEq for LazyTokenStream {
@@ -652,15 +644,14 @@ impl fmt::Debug for LazyTokenStream {
 
 impl LazyTokenStream {
     pub fn new() -> Self {
-        LazyTokenStream(Cell::new(None))
+        LazyTokenStream(Lock::new(None))
     }
 
     pub fn force<F: FnOnce() -> TokenStream>(&self, f: F) -> TokenStream {
-        let mut opt_stream = self.0.take();
+        let mut opt_stream = self.0.lock();
         if opt_stream.is_none() {
-            opt_stream = Some(f());
+            *opt_stream = Some(f());
         }
-        self.0.set(opt_stream.clone());
         opt_stream.clone().unwrap()
     }
 }