Auto merge of #21997 - Manishearth:rollup, r=alexcrichton

None

4 files changed, 63 insertions, 20 deletions

diff --git a/src/libsyntax/codemap.rs b/src/libsyntax/codemap.rs
index 00857d10f43..3231342cb50 100644
--- a/src/libsyntax/codemap.rs
+++ b/src/libsyntax/codemap.rs
@@ -437,18 +437,35 @@ impl CodeMap {
         FileLines {file: lo.file, lines: lines}
     }
 
-    pub fn span_to_snippet(&self, sp: Span) -> Option<String> {
+    pub fn span_to_snippet(&self, sp: Span) -> Result<String, SpanSnippetError> {
+        if sp.lo > sp.hi {
+            return Err(SpanSnippetError::IllFormedSpan(sp));
+        }
+
         let begin = self.lookup_byte_offset(sp.lo);
         let end = self.lookup_byte_offset(sp.hi);
 
-        // FIXME #8256: this used to be an assert but whatever precondition
-        // it's testing isn't true for all spans in the AST, so to allow the
-        // caller to not have to panic (and it can't catch it since the CodeMap
-        // isn't sendable), return None
         if begin.fm.start_pos != end.fm.start_pos {
-            None
+            return Err(SpanSnippetError::DistinctSources(DistinctSources {
+                begin: (begin.fm.name.clone(),
+                        begin.fm.start_pos),
+                end: (end.fm.name.clone(),
+                      end.fm.start_pos)
+            }));
         } else {
-            Some((&begin.fm.src[begin.pos.to_usize()..end.pos.to_usize()]).to_string())
+            let start = begin.pos.to_usize();
+            let limit = end.pos.to_usize();
+            if start > limit || limit > begin.fm.src.len() {
+                return Err(SpanSnippetError::MalformedForCodemap(
+                    MalformedCodemapPositions {
+                        name: begin.fm.name.clone(),
+                        source_len: begin.fm.src.len(),
+                        begin_pos: begin.pos,
+                        end_pos: end.pos,
+                    }));
+            }
+
+            return Ok((&begin.fm.src[start..limit]).to_string())
         }
     }
 
@@ -622,6 +639,27 @@ impl CodeMap {
     }
 }
 
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub enum SpanSnippetError {
+    IllFormedSpan(Span),
+    DistinctSources(DistinctSources),
+    MalformedForCodemap(MalformedCodemapPositions),
+}
+
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub struct DistinctSources {
+    begin: (String, BytePos),
+    end: (String, BytePos)
+}
+
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub struct MalformedCodemapPositions {
+    name: String,
+    source_len: usize,
+    begin_pos: BytePos,
+    end_pos: BytePos
+}
+
 #[cfg(test)]
 mod test {
     use super::*;
@@ -773,7 +811,7 @@ mod test {
         let span = Span {lo: BytePos(12), hi: BytePos(23), expn_id: NO_EXPANSION};
         let snippet = cm.span_to_snippet(span);
 
-        assert_eq!(snippet, Some("second line".to_string()));
+        assert_eq!(snippet, Ok("second line".to_string()));
     }
 
     #[test]
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 36701e7e25c..a93ddbb2379 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -109,7 +109,7 @@ static KNOWN_FEATURES: &'static [(&'static str, &'static str, Status)] = &[
     // int and uint are now deprecated
     ("int_uint", "1.0.0", Active),
 
-    // macro reexport needs more discusion and stabilization
+    // macro reexport needs more discussion and stabilization
     ("macro_reexport", "1.0.0", Active),
 
     // These are used to test this portion of the compiler, they don't actually
@@ -149,7 +149,10 @@ pub struct Features {
     pub old_orphan_check: bool,
     pub simd_ffi: bool,
     pub unmarked_api: bool,
-    pub lib_features: Vec<(InternedString, Span)>
+    /// spans of #![feature] attrs for stable language features. for error reporting
+    pub declared_stable_lang_features: Vec<Span>,
+    /// #![feature] attrs for non-language (library) features
+    pub declared_lib_features: Vec<(InternedString, Span)>
 }
 
 impl Features {
@@ -162,7 +165,8 @@ impl Features {
             old_orphan_check: false,
             simd_ffi: false,
             unmarked_api: false,
-            lib_features: Vec::new()
+            declared_stable_lang_features: Vec::new(),
+            declared_lib_features: Vec::new()
         }
     }
 }
@@ -511,6 +515,7 @@ fn check_crate_inner<F>(cm: &CodeMap, span_handler: &SpanHandler, krate: &ast::C
         cm: cm,
     };
 
+    let mut accepted_features = Vec::new();
     let mut unknown_features = Vec::new();
 
     for attr in &krate.attrs {
@@ -550,8 +555,7 @@ fn check_crate_inner<F>(cm: &CodeMap, span_handler: &SpanHandler, krate: &ast::C
                             span_handler.span_err(mi.span, "feature has been removed");
                         }
                         Some(&(_, _, Accepted)) => {
-                            span_handler.span_warn(mi.span, "feature has been added to Rust, \
-                                                             directive not necessary");
+                            accepted_features.push(mi.span);
                         }
                         None => {
                             unknown_features.push((name, mi.span));
@@ -572,7 +576,8 @@ fn check_crate_inner<F>(cm: &CodeMap, span_handler: &SpanHandler, krate: &ast::C
         old_orphan_check: cx.has_feature("old_orphan_check"),
         simd_ffi: cx.has_feature("simd_ffi"),
         unmarked_api: cx.has_feature("unmarked_api"),
-        lib_features: unknown_features
+        declared_stable_lang_features: accepted_features,
+        declared_lib_features: unknown_features
     }
 }
 
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index 6ff5c77f507..694da9b8b28 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -560,7 +560,7 @@ fn filtered_float_lit(data: token::InternedString, suffix: Option<&str>,
 }
 pub fn float_lit(s: &str, suffix: Option<&str>, sd: &SpanHandler, sp: Span) -> ast::Lit_ {
     debug!("float_lit: {:?}, {:?}", s, suffix);
-    // FIXME #2252: bounds checking float literals is defered until trans
+    // FIXME #2252: bounds checking float literals is deferred until trans
     let s = s.chars().filter(|&c| c != '_').collect::<String>();
     let data = token::intern_and_get_ident(&*s);
     filtered_float_lit(data, suffix, sd, sp)
@@ -1233,8 +1233,8 @@ mod test {
         let span = tts.iter().rev().next().unwrap().get_span();
 
         match sess.span_diagnostic.cm.span_to_snippet(span) {
-            Some(s) => assert_eq!(&s[], "{ body }"),
-            None => panic!("could not get snippet"),
+            Ok(s) => assert_eq!(&s[], "{ body }"),
+            Err(_) => panic!("could not get snippet"),
         }
     }
 }
diff --git a/src/libsyntax/parse/obsolete.rs b/src/libsyntax/parse/obsolete.rs
index 60de6c909b7..1df2e762ee7 100644
--- a/src/libsyntax/parse/obsolete.rs
+++ b/src/libsyntax/parse/obsolete.rs
@@ -63,15 +63,15 @@ impl<'a> ParserObsoleteMethods for parser::Parser<'a> {
                 "use a `move ||` expression instead",
             ),
             ObsoleteSyntax::ClosureType => (
-                "`|usize| -> bool` closure type syntax",
+                "`|usize| -> bool` closure type",
                 "use unboxed closures instead, no type annotation needed"
             ),
             ObsoleteSyntax::ClosureKind => (
-                "`:`, `&mut:`, or `&:` syntax",
+                "`:`, `&mut:`, or `&:`",
                 "rely on inference instead"
             ),
             ObsoleteSyntax::Sized => (
-                "`Sized? T` syntax for removing the `Sized` bound",
+                "`Sized? T` for removing the `Sized` bound",
                 "write `T: ?Sized` instead"
             ),
         };