stylo: Update rust-cssparser; extract more specific error types when reporting (bug 1352669).

21 files changed, 318 insertions, 80 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 02ee71c6823..1e1b8d66c47 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -325,7 +325,7 @@ version = "0.0.1"
 dependencies = [
  "azure 0.19.0 (git+https://github.com/servo/rust-azure)",
  "canvas_traits 0.0.1",
- "cssparser 0.16.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "gleam 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -340,7 +340,7 @@ dependencies = [
 name = "canvas_traits"
 version = "0.0.1"
 dependencies = [
- "cssparser 0.16.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "heapsize 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "heapsize_derive 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -585,7 +585,7 @@ dependencies = [
 
 [[package]]
 name = "cssparser"
-version = "0.16.1"
+version = "0.17.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cssparser-macros 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1017,7 +1017,7 @@ name = "geckoservo"
 version = "0.0.1"
 dependencies = [
  "atomic_refcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.16.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1083,7 +1083,7 @@ dependencies = [
 name = "gfx_tests"
 version = "0.0.1"
 dependencies = [
- "cssparser 0.16.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "gfx 0.0.1",
  "ipc-channel 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
@@ -2418,7 +2418,7 @@ dependencies = [
  "caseless 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "cmake 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "cookie 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.16.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "deny_public_fields 0.0.1",
  "devtools_traits 0.0.1",
  "dom_struct 0.0.1",
@@ -2491,7 +2491,7 @@ dependencies = [
  "app_units 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "atomic_refcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "canvas_traits 0.0.1",
- "cssparser 0.16.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "gfx_traits 0.0.1",
  "heapsize 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2562,7 +2562,7 @@ name = "selectors"
 version = "0.19.0"
 dependencies = [
  "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.16.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "matches 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2954,7 +2954,7 @@ dependencies = [
  "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cfg-if 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.16.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "encoding 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3007,7 +3007,7 @@ version = "0.0.1"
 dependencies = [
  "app_units 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.16.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "html5ever 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3028,7 +3028,7 @@ version = "0.0.1"
 dependencies = [
  "app_units 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.16.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "heapsize 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "heapsize_derive 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3041,7 +3041,7 @@ name = "stylo_tests"
 version = "0.0.1"
 dependencies = [
  "atomic_refcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.16.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "geckoservo 0.0.1",
@@ -3624,7 +3624,7 @@ dependencies = [
 "checksum core-foundation-sys 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "41115a6aa5d3e1e5ef98148373f25971d1fad53818553f216495f9e67e90a624"
 "checksum core-graphics 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a9f841e9637adec70838c537cae52cb4c751cc6514ad05669b51d107c2021c79"
 "checksum core-text 5.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "74ba2a7abdccb94fb6c00822addef48504182b285aa45a30e78286487888fcb4"
-"checksum cssparser 0.16.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2842253baded8e712e9d8d80ebfe5ea8e95c5b27071e6a6db6080ca1e81c07d1"
+"checksum cssparser 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e7063452c60432cb306ed54d538178c20792d47fa960c240ce6c083239ee55ec"
 "checksum cssparser-macros 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "079adec4af52bb5275eadd004292028c79eb3c5f5b4ee8086a36d4197032f6df"
 "checksum dbghelp-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "97590ba53bcb8ac28279161ca943a924d1fd4a8fb3fa63302591647c4fc5b850"
 "checksum dbus 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "4aee01fb76ada3e5e7ca642ea6664ebf7308a810739ca2aca44909a1191ac254"
diff --git a/components/canvas/Cargo.toml b/components/canvas/Cargo.toml
index 42e8b853e53..cb9b9801937 100644
--- a/components/canvas/Cargo.toml
+++ b/components/canvas/Cargo.toml
@@ -12,7 +12,7 @@ path = "lib.rs"
 [dependencies]
 azure = {git = "https://github.com/servo/rust-azure"}
 canvas_traits = {path = "../canvas_traits"}
-cssparser = "0.16.1"
+cssparser = "0.17.0"
 euclid = "0.15"
 gleam = "0.4"
 ipc-channel = "0.8"
diff --git a/components/canvas_traits/Cargo.toml b/components/canvas_traits/Cargo.toml
index 1c6ca6bb1a4..d9cbf34cb75 100644
--- a/components/canvas_traits/Cargo.toml
+++ b/components/canvas_traits/Cargo.toml
@@ -10,7 +10,7 @@ name = "canvas_traits"
 path = "lib.rs"
 
 [dependencies]
-cssparser = "0.16.1"
+cssparser = "0.17.0"
 euclid = "0.15"
 heapsize = "0.4"
 heapsize_derive = "0.1"
diff --git a/components/script/Cargo.toml b/components/script/Cargo.toml
index 12f84eeaf12..c9ce38c1f35 100644
--- a/components/script/Cargo.toml
+++ b/components/script/Cargo.toml
@@ -35,7 +35,7 @@ byteorder = "1.0"
 canvas_traits = {path = "../canvas_traits"}
 caseless = "0.1.0"
 cookie = "0.6"
-cssparser = "0.16.1"
+cssparser = "0.17.0"
 deny_public_fields = {path = "../deny_public_fields"}
 devtools_traits = {path = "../devtools_traits"}
 dom_struct = {path = "../dom_struct"}
diff --git a/components/script_layout_interface/Cargo.toml b/components/script_layout_interface/Cargo.toml
index 73d1f506636..6a74eeda086 100644
--- a/components/script_layout_interface/Cargo.toml
+++ b/components/script_layout_interface/Cargo.toml
@@ -13,7 +13,7 @@ path = "lib.rs"
 app_units = "0.5"
 atomic_refcell = "0.1"
 canvas_traits = {path = "../canvas_traits"}
-cssparser = "0.16.1"
+cssparser = "0.17.0"
 euclid = "0.15"
 gfx_traits = {path = "../gfx_traits"}
 heapsize = "0.4"
diff --git a/components/selectors/Cargo.toml b/components/selectors/Cargo.toml
index 4a1ad7dd894..8a8ddfda946 100644
--- a/components/selectors/Cargo.toml
+++ b/components/selectors/Cargo.toml
@@ -25,7 +25,7 @@ unstable = []
 [dependencies]
 bitflags = "0.7"
 matches = "0.1"
-cssparser = "0.16.1"
+cssparser = "0.17.0"
 log = "0.3"
 fnv = "1.0"
 phf = "0.7.18"
diff --git a/components/selectors/parser.rs b/components/selectors/parser.rs
index f341911a33c..676c1946822 100644
--- a/components/selectors/parser.rs
+++ b/components/selectors/parser.rs
@@ -59,7 +59,7 @@ pub enum SelectorParseError<'i, T> {
     PseudoElementExpectedIdent,
     UnsupportedPseudoClass,
     UnexpectedIdent(CompactCowStr<'i>),
-    ExpectedNamespace,
+    ExpectedNamespace(CompactCowStr<'i>),
     Custom(T),
 }
 
@@ -1105,9 +1105,10 @@ fn parse_qualified_name<'i, 't, P, E, Impl>
             let position = input.position();
             match input.next_including_whitespace() {
                 Ok(Token::Delim('|')) => {
-                    let prefix = from_cow_str(value.into());
+                    let prefix = from_cow_str(value.clone().into());
                     let result = parser.namespace_for_prefix(&prefix);
-                    let url = result.ok_or(ParseError::Custom(SelectorParseError::ExpectedNamespace))?;
+                    let url = result.ok_or(ParseError::Custom(
+                        SelectorParseError::ExpectedNamespace(value.into())))?;
                     explicit_namespace(input, QNamePrefix::ExplicitNamespace(prefix, url))
                 },
                 _ => {
diff --git a/components/style/Cargo.toml b/components/style/Cargo.toml
index 29a77455833..c6d23ab2b8c 100644
--- a/components/style/Cargo.toml
+++ b/components/style/Cargo.toml
@@ -38,7 +38,7 @@ bitflags = "0.7"
 bit-vec = "0.4.3"
 byteorder = "1.0"
 cfg-if = "0.1.0"
-cssparser = "0.16.1"
+cssparser = "0.17.0"
 encoding = {version = "0.2", optional = true}
 euclid = "0.15"
 fnv = "1.0"
diff --git a/components/style/custom_properties.rs b/components/style/custom_properties.rs
index 5b7c125739a..0f22a0b075c 100644
--- a/components/style/custom_properties.rs
+++ b/components/style/custom_properties.rs
@@ -280,10 +280,10 @@ fn parse_declaration_value_block<'i, 't>
                 }
                 token.serialization_type()
             }
-            Token::BadUrl =>
-                return Err(StyleParseError::BadUrlInDeclarationValueBlock.into()),
-            Token::BadString =>
-                return Err(StyleParseError::BadStringInDeclarationValueBlock.into()),
+            Token::BadUrl(u) =>
+                return Err(StyleParseError::BadUrlInDeclarationValueBlock(u).into()),
+            Token::BadString(s) =>
+                return Err(StyleParseError::BadStringInDeclarationValueBlock(s).into()),
             Token::CloseParenthesis =>
                 return Err(StyleParseError::UnbalancedCloseParenthesisInDeclarationValueBlock.into()),
             Token::CloseSquareBracket =>
diff --git a/components/style/error_reporting.rs b/components/style/error_reporting.rs
index eda926f8cf3..09b7abf1c1d 100644
--- a/components/style/error_reporting.rs
+++ b/components/style/error_reporting.rs
@@ -76,8 +76,8 @@ impl<'a> ContextualParseError<'a> {
                 Token::ParenthesisBlock => format!("parenthesis ("),
                 Token::SquareBracketBlock => format!("square bracket ["),
                 Token::CurlyBracketBlock => format!("curly bracket {{"),
-                Token::BadUrl => format!("bad url parse error"),
-                Token::BadString => format!("bad string parse error"),
+                Token::BadUrl(ref _u) => format!("bad url parse error"),
+                Token::BadString(ref _s) => format!("bad string parse error"),
                 Token::CloseParenthesis => format!("unmatched close parenthesis"),
                 Token::CloseSquareBracket => format!("unmatched close square bracket"),
                 Token::CloseCurlyBracket => format!("unmatched close curly bracket"),
@@ -88,11 +88,11 @@ impl<'a> ContextualParseError<'a> {
             match *err {
                 CssParseError::Basic(BasicParseError::UnexpectedToken(ref t)) =>
                     format!("found unexpected {}", token_to_str(t)),
-                CssParseError::Basic(BasicParseError::ExpectedToken(ref t)) =>
-                    format!("expected {}", token_to_str(t)),
                 CssParseError::Basic(BasicParseError::EndOfInput) =>
                     format!("unexpected end of input"),
-                CssParseError::Basic(BasicParseError::AtRuleInvalid) =>
+                CssParseError::Basic(BasicParseError::AtRuleInvalid(ref i)) =>
+                    format!("@ rule invalid: {}", i),
+                CssParseError::Basic(BasicParseError::AtRuleBodyInvalid) =>
                     format!("@ rule invalid"),
                 CssParseError::Basic(BasicParseError::QualifiedRuleInvalid) =>
                     format!("qualified rule invalid"),
diff --git a/components/style/properties/declaration_block.rs b/components/style/properties/declaration_block.rs
index a6695b7b40d..5a6eed8c5af 100644
--- a/components/style/properties/declaration_block.rs
+++ b/components/style/properties/declaration_block.rs
@@ -908,10 +908,17 @@ pub fn parse_one_declaration_into(declarations: &mut SourcePropertyDeclaration,
                                      parsing_mode,
                                      quirks_mode);
     let mut input = ParserInput::new(input);
-    Parser::new(&mut input).parse_entirely(|parser| {
+    let mut parser = Parser::new(&mut input);
+    let start = parser.position();
+    parser.parse_entirely(|parser| {
         PropertyDeclaration::parse_into(declarations, id, &context, parser)
             .map_err(|e| e.into())
-    }).map_err(|_| ())
+    }).map_err(|err| {
+        let end = parser.position();
+        let error = ContextualParseError::UnsupportedPropertyDeclaration(
+            parser.slice(start..end), err);
+        log_css_error(&mut parser, start, error, &context);
+    })
 }
 
 /// A struct to parse property declarations.
diff --git a/components/style/properties/properties.mako.rs b/components/style/properties/properties.mako.rs
index 2c6c7971846..de94c5a0fca 100644
--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@@ -37,7 +37,8 @@ use properties::animated_properties::AnimatableLonghand;
 use selectors::parser::SelectorParseError;
 #[cfg(feature = "servo")] use servo_config::prefs::PREFS;
 use shared_lock::StylesheetGuards;
-use style_traits::{PARSING_MODE_DEFAULT, HasViewportPercentage, ToCss, ParseError, PropertyDeclarationParseError};
+use style_traits::{PARSING_MODE_DEFAULT, HasViewportPercentage, ToCss, ParseError};
+use style_traits::{PropertyDeclarationParseError, StyleParseError};
 use stylesheets::{CssRuleType, MallocSizeOf, MallocSizeOfFn, Origin, UrlExtraData};
 #[cfg(feature = "servo")] use values::Either;
 use values::generics::text::LineHeight;
@@ -1009,7 +1010,7 @@ impl PropertyId {
         match static_id(&property_name) {
             Some(&StaticId::Longhand(id)) => Ok(PropertyId::Longhand(id)),
             Some(&StaticId::Shorthand(id)) => Ok(PropertyId::Shorthand(id)),
-            None => Err(SelectorParseError::UnexpectedIdent(property_name).into()),
+            None => Err(StyleParseError::UnknownProperty(property_name).into()),
         }
     }
 
@@ -1414,7 +1415,7 @@ impl PropertyDeclaration {
                     Ok(keyword) => DeclaredValueOwned::CSSWideKeyword(keyword),
                     Err(_) => match ::custom_properties::SpecifiedValue::parse(context, input) {
                         Ok(value) => DeclaredValueOwned::Value(value),
-                        Err(_) => return Err(PropertyDeclarationParseError::InvalidValue),
+                        Err(_) => return Err(PropertyDeclarationParseError::InvalidValue(name.to_string())),
                     }
                 };
                 declarations.push(PropertyDeclaration::Custom(name, value));
@@ -1442,7 +1443,7 @@ impl PropertyDeclaration {
                                 declarations.push(value);
                                 Ok(())
                             },
-                            Err(_) => Err(PropertyDeclarationParseError::InvalidValue),
+                            Err(_) => Err(PropertyDeclarationParseError::InvalidValue("${property.ident}".into())),
                         }
                     % else:
                         Err(PropertyDeclarationParseError::UnknownProperty)
@@ -1482,7 +1483,7 @@ impl PropertyDeclaration {
                         },
                         Err(_) => {
                             shorthands::${shorthand.ident}::parse_into(declarations, context, input)
-                                .map_err(|_| PropertyDeclarationParseError::InvalidValue)
+                                .map_err(|_| PropertyDeclarationParseError::InvalidValue("${shorthand.ident}".into()))
                         }
                     }
                 }
diff --git a/components/style/stylesheets/rule_parser.rs b/components/style/stylesheets/rule_parser.rs
index b622ef1001a..3e9872b5a1c 100644
--- a/components/style/stylesheets/rule_parser.rs
+++ b/components/style/stylesheets/rule_parser.rs
@@ -7,7 +7,7 @@
 use {Namespace, Prefix};
 use counter_style::{parse_counter_style_body, parse_counter_style_name};
 use cssparser::{AtRuleParser, AtRuleType, Parser, QualifiedRuleParser, RuleListParser};
-use cssparser::{CompactCowStr, SourceLocation};
+use cssparser::{CompactCowStr, SourceLocation, BasicParseError};
 use error_reporting::ContextualParseError;
 use font_face::parse_font_face_block;
 use media_queries::{parse_media_query_list, MediaList};
@@ -184,7 +184,13 @@ impl<'a, 'i> AtRuleParser<'i> for TopLevelRuleParser<'a> {
                 self.state = State::Namespaces;
 
                 let prefix_result = input.try(|input| input.expect_ident());
-                let url = Namespace::from(Cow::from(input.expect_url_or_string()?));
+                let maybe_namespace = match input.expect_url_or_string() {
+                    Ok(url_or_string) => url_or_string,
+                    Err(BasicParseError::UnexpectedToken(t)) =>
+                        return Err(StyleParseError::UnexpectedTokenWithinNamespace(t).into()),
+                    Err(e) => return Err(e.into()),
+                };
+                let url = Namespace::from(Cow::from(maybe_namespace));
 
                 let id = register_namespace(&url)
                     .map_err(|()| StyleParseError::UnspecifiedError)?;
@@ -509,7 +515,7 @@ fn get_location_with_offset(
     offset: u64
 ) -> SourceLocation {
     SourceLocation {
-        line: location.line + offset as u32 - 1,
+        line: location.line + offset as u32,
         column: location.column,
     }
 }
diff --git a/components/style_traits/Cargo.toml b/components/style_traits/Cargo.toml
index feeeb7c786a..3473d710353 100644
--- a/components/style_traits/Cargo.toml
+++ b/components/style_traits/Cargo.toml
@@ -16,7 +16,7 @@ gecko = []
 [dependencies]
 app_units = "0.5"
 bitflags = "0.7"
-cssparser = "0.16.1"
+cssparser = "0.17.0"
 euclid = "0.15"
 heapsize = {version = "0.4", optional = true}
 heapsize_derive = {version = "0.1", optional = true}
diff --git a/components/style_traits/lib.rs b/components/style_traits/lib.rs
index 7cb28e7f7c7..d6336ca9e0c 100644
--- a/components/style_traits/lib.rs
+++ b/components/style_traits/lib.rs
@@ -22,7 +22,7 @@ extern crate euclid;
 extern crate selectors;
 #[cfg(feature = "servo")] #[macro_use] extern crate serde;
 
-use cssparser::CompactCowStr;
+use cssparser::{CompactCowStr, Token};
 use selectors::parser::SelectorParseError;
 
 /// Opaque type stored in type-unsafe work queues for parallel layout.
@@ -81,9 +81,9 @@ pub type ParseError<'i> = cssparser::ParseError<'i, SelectorParseError<'i, Style
 /// Errors that can be encountered while parsing CSS values.
 pub enum StyleParseError<'i> {
     /// A bad URL token in a DVB.
-    BadUrlInDeclarationValueBlock,
+    BadUrlInDeclarationValueBlock(CompactCowStr<'i>),
     /// A bad string token in a DVB.
-    BadStringInDeclarationValueBlock,
+    BadStringInDeclarationValueBlock(CompactCowStr<'i>),
     /// Unexpected closing parenthesis in a DVB.
     UnbalancedCloseParenthesisInDeclarationValueBlock,
     /// Unexpected closing bracket in a DVB.
@@ -110,17 +110,21 @@ pub enum StyleParseError<'i> {
     UnsupportedAtRule(CompactCowStr<'i>),
     /// A placeholder for many sources of errors that require more specific variants.
     UnspecifiedError,
+    /// An unexpected token was found within a namespace rule.
+    UnexpectedTokenWithinNamespace(Token<'i>),
+    /// An unknown CSS property was encountered.
+    UnknownProperty(CompactCowStr<'i>),
 }
 
 /// The result of parsing a property declaration.
-#[derive(Eq, PartialEq, Copy, Clone, Debug)]
+#[derive(Eq, PartialEq, Clone, Debug)]
 pub enum PropertyDeclarationParseError {
     /// The property declaration was for an unknown property.
     UnknownProperty,
     /// The property declaration was for a disabled experimental property.
     ExperimentalProperty,
     /// The property declaration contained an invalid value.
-    InvalidValue,
+    InvalidValue(String),
     /// The declaration contained an animation property, and we were parsing
     /// this as a keyframe block (so that property should be ignored).
     ///
diff --git a/ports/geckolib/Cargo.toml b/ports/geckolib/Cargo.toml
index d63a2819fe1..5c50eb6bf7a 100644
--- a/ports/geckolib/Cargo.toml
+++ b/ports/geckolib/Cargo.toml
@@ -16,7 +16,7 @@ gecko_debug = ["style/gecko_debug"]
 
 [dependencies]
 atomic_refcell = "0.1"
-cssparser = "0.16.1"
+cssparser = "0.17.0"
 env_logger = {version = "0.4", default-features = false} # disable `regex` to reduce code size
 libc = "0.2"
 log = {version = "0.3.5", features = ["release_max_level_info"]}
diff --git a/ports/geckolib/error_reporter.rs b/ports/geckolib/error_reporter.rs
index 77ce1f4ea12..cb7fae7e1a5 100644
--- a/ports/geckolib/error_reporter.rs
+++ b/ports/geckolib/error_reporter.rs
@@ -6,7 +6,9 @@
 
 #![allow(unsafe_code)]
 
-use cssparser::{Parser, SourcePosition};
+use cssparser::{Parser, SourcePosition, ParseError as CssParseError, Token, BasicParseError};
+use cssparser::CompactCowStr;
+use selectors::parser::SelectorParseError;
 use style::error_reporting::{ParseErrorReporter, ContextualParseError};
 use style::gecko_bindings::bindings::{Gecko_CreateCSSErrorReporter, Gecko_DestroyCSSErrorReporter};
 use style::gecko_bindings::bindings::Gecko_ReportUnexpectedCSSError;
@@ -15,6 +17,7 @@ use style::gecko_bindings::structs::ErrorReporter as GeckoErrorReporter;
 use style::gecko_bindings::structs::URLExtraData as RawUrlExtraData;
 use style::gecko_bindings::sugar::refptr::RefPtr;
 use style::stylesheets::UrlExtraData;
+use style_traits::{ParseError, StyleParseError, PropertyDeclarationParseError};
 
 /// Wrapper around an instance of Gecko's CSS error reporter.
 pub struct ErrorReporter(*mut GeckoErrorReporter);
@@ -39,25 +42,239 @@ impl Drop for ErrorReporter {
     }
 }
 
+enum ErrorString<'a> {
+    Snippet(CompactCowStr<'a>),
+    Ident(CompactCowStr<'a>),
+    UnexpectedToken(Token<'a>),
+}
+
+impl<'a> ErrorString<'a> {
+    fn into_str(self) -> String {
+        match self {
+            ErrorString::Snippet(s) => s.into_owned(),
+            ErrorString::Ident(i) => escape_css_ident(&i),
+            ErrorString::UnexpectedToken(t) => token_to_str(t),
+        }
+    }
+}
+
+// This is identical to the behaviour of cssparser::serialize_identifier, except that
+// it uses numerical escapes for a larger set of characters.
+fn escape_css_ident(ident: &str) -> String {
+    // The relevant parts of the CSS grammar are:
+    //   ident    ([-]?{nmstart}|[-][-]){nmchar}*
+    //   nmstart  [_a-z]|{nonascii}|{escape}
+    //   nmchar   [_a-z0-9-]|{nonascii}|{escape}
+    //   nonascii [^\0-\177]
+    //   escape   {unicode}|\\[^\n\r\f0-9a-f]
+    //   unicode  \\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?
+    // from http://www.w3.org/TR/CSS21/syndata.html#tokenization but
+    // modified for idents by
+    // http://dev.w3.org/csswg/cssom/#serialize-an-identifier and
+    // http://dev.w3.org/csswg/css-syntax/#would-start-an-identifier
+    if ident.is_empty() {
+        return ident.into()
+    }
+
+    let mut escaped = String::new();
+
+    // A leading dash does not need to be escaped as long as it is not the
+    // *only* character in the identifier.
+    let mut iter = ident.chars().peekable();
+    if iter.peek() == Some(&'-') {
+        if ident.len() == 1 {
+            return "\\-".into();
+        }
+
+        escaped.push('-');
+        // Skip the first character.
+        let _ = iter.next();
+    }
+
+    // Escape a digit at the start (including after a dash),
+    // numerically.  If we didn't escape it numerically, it would get
+    // interpreted as a numeric escape for the wrong character.
+    if iter.peek().map_or(false, |&c| '0' <= c && c <= '9') {
+        let ch = iter.next().unwrap();
+        escaped.push_str(&format!("\\{:x} ", ch as u32));
+    }
+
+    while let Some(ch) = iter.next() {
+        if ch == '\0' {
+            escaped.push_str("\u{FFFD}");
+        } else if ch < (0x20 as char) || (0x7f as char <= ch && ch < (0xA0 as char)) {
+            // Escape U+0000 through U+001F and U+007F through U+009F numerically.
+            escaped.push_str(&format!("\\{:x} ", ch as u32));
+        } else {
+            // Escape ASCII non-identifier printables as a backslash plus
+            // the character.
+            if (ch < (0x7F as char)) &&
+                ch != '_' && ch != '-' &&
+                (ch < '0' || '9' < ch) &&
+                (ch < 'A' || 'Z' < ch) &&
+                (ch < 'a' || 'z' < ch)
+            {
+                escaped.push('\\');
+            }
+            escaped.push(ch);
+        }
+    }
+
+    escaped
+}
+
+// This is identical to the behaviour of cssparser::CssStringWriter, except that
+// the characters between 0x7F and 0xA0 as numerically escaped as well.
+fn escape_css_string(s: &str) -> String {
+    let mut escaped = String::new();
+    for ch in s.chars() {
+        if ch < ' ' || (ch >= (0x7F as char) && ch < (0xA0 as char)) {
+            escaped.push_str(&format!("\\{:x} ", ch as u32));
+        } else {
+            if ch == '"' || ch == '\'' || ch == '\\' {
+                // Escape backslash and quote characters symbolically.
+                // It's not technically necessary to escape the quote
+                // character that isn't being used to delimit the string,
+                // but we do it anyway because that makes testing simpler.
+                escaped.push('\\');
+            }
+            escaped.push(ch);
+        }
+    }
+    escaped
+}
+
+fn token_to_str<'a>(t: Token<'a>) -> String {
+    match t {
+        Token::Ident(i) => escape_css_ident(&i),
+        Token::AtKeyword(kw) => format!("@{}", escape_css_ident(&kw)),
+        Token::Hash(h) | Token::IDHash(h) => format!("#{}", escape_css_ident(&h)),
+        Token::QuotedString(s) => format!("'{}'", escape_css_string(&s)),
+        Token::UnquotedUrl(u) => format!("'{}'", escape_css_string(&u)),
+        Token::Delim(d) => d.to_string(),
+        Token::Number { int_value: Some(i), .. } => i.to_string(),
+        Token::Number { value, .. } => value.to_string(),
+        Token::Percentage { int_value: Some(i), .. } => i.to_string(),
+        Token::Percentage { unit_value, .. } => unit_value.to_string(),
+        Token::Dimension { int_value: Some(i), ref unit, .. } =>
+            format!("{}{}", i.to_string(), escape_css_ident(&unit.to_string())),
+        Token::Dimension { value, ref unit, .. } =>
+            format!("{}{}", value.to_string(), escape_css_ident(&unit.to_string())),
+        Token::WhiteSpace(_) => "whitespace".into(),
+        Token::Comment(_) => "comment".into(),
+        Token::Colon => ":".into(),
+        Token::Semicolon => ";".into(),
+        Token::Comma => ",".into(),
+        Token::IncludeMatch => "~=".into(),
+        Token::DashMatch => "|=".into(),
+        Token::PrefixMatch => "^=".into(),
+        Token::SuffixMatch => "$=".into(),
+        Token::SubstringMatch => "*=".into(),
+        Token::Column => "||".into(),
+        Token::CDO => "<!--".into(),
+        Token::CDC => "-->".into(),
+        Token::Function(f) => format!("{}(", escape_css_ident(&f)),
+        Token::ParenthesisBlock => "(".into(),
+        Token::SquareBracketBlock => "[".into(),
+        Token::CurlyBracketBlock => "{".into(),
+        Token::BadUrl(url) => format!("url('{}", escape_css_string(&url)).into(),
+        Token::BadString(s) => format!("'{}", escape_css_string(&s)).into(),
+        Token::CloseParenthesis => "unmatched close parenthesis".into(),
+        Token::CloseSquareBracket => "unmatched close square bracket".into(),
+        Token::CloseCurlyBracket => "unmatched close curly bracket".into(),
+    }
+}
+
 trait ErrorHelpers<'a> {
-    fn to_gecko_message(&self) -> (&'static [u8], &'a str);
+    fn error_data(self) -> (CompactCowStr<'a>, ParseError<'a>);
+    fn error_param(self) -> ErrorString<'a>;
+    fn to_gecko_message(&self) -> &'static [u8];
 }
 
 impl<'a> ErrorHelpers<'a> for ContextualParseError<'a> {
-    fn to_gecko_message(&self) -> (&'static [u8], &'a str) {
+    fn error_data(self) -> (CompactCowStr<'a>, ParseError<'a>) {
+        match self {
+            ContextualParseError::UnsupportedPropertyDeclaration(s, err) |
+            ContextualParseError::UnsupportedFontFaceDescriptor(s, err) |
+            ContextualParseError::InvalidKeyframeRule(s, err) |
+            ContextualParseError::UnsupportedKeyframePropertyDeclaration(s, err) |
+            ContextualParseError::InvalidRule(s, err) |
+            ContextualParseError::UnsupportedRule(s, err) |
+            ContextualParseError::UnsupportedViewportDescriptorDeclaration(s, err) |
+            ContextualParseError::UnsupportedCounterStyleDescriptorDeclaration(s, err) =>
+                (s.into(), err),
+            ContextualParseError::InvalidCounterStyleWithoutSymbols(s) |
+            ContextualParseError::InvalidCounterStyleNotEnoughSymbols(s) =>
+                (s.into(), StyleParseError::UnspecifiedError.into()),
+            ContextualParseError::InvalidCounterStyleWithoutAdditiveSymbols |
+            ContextualParseError::InvalidCounterStyleExtendsWithSymbols |
+            ContextualParseError::InvalidCounterStyleExtendsWithAdditiveSymbols =>
+                ("".into(), StyleParseError::UnspecifiedError.into())
+        }
+    }
+
+    fn error_param(self) -> ErrorString<'a> {
+        match self.error_data() {
+            (_, CssParseError::Basic(BasicParseError::UnexpectedToken(t))) =>
+                ErrorString::UnexpectedToken(t),
+
+            (_, CssParseError::Basic(BasicParseError::AtRuleInvalid(i))) =>
+                ErrorString::Snippet(format!("@{}", escape_css_ident(&i)).into()),
+
+            (_, CssParseError::Custom(SelectorParseError::Custom(
+                StyleParseError::PropertyDeclaration(
+                    PropertyDeclarationParseError::InvalidValue(property))))) =>
+                ErrorString::Snippet(property.into()),
+
+            (_, CssParseError::Custom(SelectorParseError::UnexpectedIdent(ident))) =>
+                ErrorString::Ident(ident),
+
+            (_, CssParseError::Custom(SelectorParseError::ExpectedNamespace(namespace))) =>
+                ErrorString::Ident(namespace),
+
+            (_, CssParseError::Custom(SelectorParseError::Custom(
+                StyleParseError::UnknownProperty(property)))) =>
+                ErrorString::Ident(property),
+
+            (_, CssParseError::Custom(SelectorParseError::Custom(
+                StyleParseError::UnexpectedTokenWithinNamespace(token)))) =>
+                ErrorString::UnexpectedToken(token),
+
+            (s, _)  => ErrorString::Snippet(s)
+        }
+    }
+
+    fn to_gecko_message(&self) -> &'static [u8] {
         match *self {
-            ContextualParseError::UnsupportedPropertyDeclaration(decl, _) =>
-                (b"PEUnknownProperty\0", decl),
-            ContextualParseError::UnsupportedFontFaceDescriptor(decl, _) =>
-                (b"PEUnknwnFontDesc\0", decl),
-            ContextualParseError::InvalidKeyframeRule(rule, _) =>
-                (b"PEKeyframeBadName\0", rule),
-            ContextualParseError::UnsupportedKeyframePropertyDeclaration(decl, _) =>
-                (b"PEBadSelectorKeyframeRuleIgnored\0", decl),
-            ContextualParseError::InvalidRule(rule, _) =>
-                (b"PEDeclDropped\0", rule),
-            ContextualParseError::UnsupportedRule(rule, _) =>
-                (b"PEDeclDropped\0", rule),
+            ContextualParseError::UnsupportedPropertyDeclaration(
+                _, CssParseError::Basic(BasicParseError::UnexpectedToken(_))) |
+            ContextualParseError::UnsupportedPropertyDeclaration(
+                _, CssParseError::Basic(BasicParseError::AtRuleInvalid(_))) =>
+                b"PEParseDeclarationDeclExpected\0",
+            ContextualParseError::UnsupportedPropertyDeclaration(
+                _, CssParseError::Custom(SelectorParseError::Custom(
+                    StyleParseError::PropertyDeclaration(
+                        PropertyDeclarationParseError::InvalidValue(_))))) =>
+                b"PEValueParsingError\0",
+            ContextualParseError::UnsupportedPropertyDeclaration(..) =>
+                b"PEUnknownProperty\0",
+            ContextualParseError::UnsupportedFontFaceDescriptor(..) =>
+                b"PEUnknwnFontDesc\0",
+            ContextualParseError::InvalidKeyframeRule(..) =>
+                b"PEKeyframeBadName\0",
+            ContextualParseError::UnsupportedKeyframePropertyDeclaration(..) =>
+                b"PEBadSelectorKeyframeRuleIgnored\0",
+            ContextualParseError::InvalidRule(
+                _, CssParseError::Custom(SelectorParseError::ExpectedNamespace(_))) =>
+                b"PEUnknownNamespacePrefix\0",
+            ContextualParseError::InvalidRule(
+                _, CssParseError::Custom(SelectorParseError::Custom(
+                StyleParseError::UnexpectedTokenWithinNamespace(_)))) =>
+                b"PEAtNSUnexpected\0",
+            ContextualParseError::InvalidRule(..) =>
+                b"PEBadSelectorRSIgnored\0",
+            ContextualParseError::UnsupportedRule(..) =>
+                b"PEDeclDropped\0",
             ContextualParseError::UnsupportedViewportDescriptorDeclaration(..) |
             ContextualParseError::UnsupportedCounterStyleDescriptorDeclaration(..) |
             ContextualParseError::InvalidCounterStyleWithoutSymbols(..) |
@@ -65,7 +282,7 @@ impl<'a> ErrorHelpers<'a> for ContextualParseError<'a> {
             ContextualParseError::InvalidCounterStyleWithoutAdditiveSymbols |
             ContextualParseError::InvalidCounterStyleExtendsWithSymbols |
             ContextualParseError::InvalidCounterStyleExtendsWithAdditiveSymbols =>
-                (b"PEUnknownAtRule\0", ""),
+                b"PEUnknownAtRule\0",
         }
     }
 }
@@ -80,8 +297,9 @@ impl ParseErrorReporter for ErrorReporter {
         let location = input.source_location(position);
         let line_number = location.line + line_number_offset as u32;
 
-        let (name, param) = error.to_gecko_message();
-        let source = "";
+        let name = error.to_gecko_message();
+        let param = error.error_param().into_str();
+        let source = input.current_line();
         unsafe {
             Gecko_ReportUnexpectedCSSError(self.0,
                                            name.as_ptr() as *const _,
diff --git a/tests/unit/gfx/Cargo.toml b/tests/unit/gfx/Cargo.toml
index 078ebb41aa9..ac840b7b2e8 100644
--- a/tests/unit/gfx/Cargo.toml
+++ b/tests/unit/gfx/Cargo.toml
@@ -10,7 +10,7 @@ path = "lib.rs"
 doctest = false
 
 [dependencies]
-cssparser = "0.16.1"
+cssparser = "0.17.0"
 gfx = {path = "../../../components/gfx"}
 ipc-channel = "0.8"
 style = {path = "../../../components/style"}
diff --git a/tests/unit/style/Cargo.toml b/tests/unit/style/Cargo.toml
index ed9b3cff1b6..f5121de85a3 100644
--- a/tests/unit/style/Cargo.toml
+++ b/tests/unit/style/Cargo.toml
@@ -15,7 +15,7 @@ testing = ["style/testing"]
 [dependencies]
 byteorder = "1.0"
 app_units = "0.5"
-cssparser = "0.16.1"
+cssparser = "0.17.0"
 euclid = "0.15"
 html5ever = "0.18"
 parking_lot = "0.3"
diff --git a/tests/unit/style/stylesheets.rs b/tests/unit/style/stylesheets.rs
index 6761be36ff2..9f72573db32 100644
--- a/tests/unit/style/stylesheets.rs
+++ b/tests/unit/style/stylesheets.rs
@@ -84,7 +84,7 @@ fn test_parse_stylesheet() {
                     url: NsAtom::from("http://www.w3.org/1999/xhtml"),
                     source_location: SourceLocation {
                         line: 1,
-                        column: 19,
+                        column: 18,
                     },
                 }))),
                 CssRule::Style(Arc::new(stylesheet.shared_lock.wrap(StyleRule {
@@ -114,7 +114,7 @@ fn test_parse_stylesheet() {
                     ]))),
                     source_location: SourceLocation {
                         line: 3,
-                        column: 9,
+                        column: 8,
                     },
                 }))),
                 CssRule::Style(Arc::new(stylesheet.shared_lock.wrap(StyleRule {
@@ -141,7 +141,7 @@ fn test_parse_stylesheet() {
                     ]))),
                     source_location: SourceLocation {
                         line: 11,
-                        column: 9,
+                        column: 8,
                     },
                 }))),
                 CssRule::Style(Arc::new(stylesheet.shared_lock.wrap(StyleRule {
@@ -203,7 +203,7 @@ fn test_parse_stylesheet() {
                     ]))),
                     source_location: SourceLocation {
                         line: 15,
-                        column: 9,
+                        column: 8,
                     },
                 }))),
                 CssRule::Keyframes(Arc::new(stylesheet.shared_lock.wrap(KeyframesRule {
@@ -235,7 +235,7 @@ fn test_parse_stylesheet() {
                     vendor_prefix: None,
                     source_location: SourceLocation {
                         line: 16,
-                        column: 19,
+                        column: 18,
                     },
                 })))
 
@@ -314,15 +314,16 @@ fn test_report_error_stylesheet() {
     let mut errors = errors.lock().unwrap();
 
     let error = errors.pop().unwrap();
-    assert_eq!("Unsupported property declaration: 'invalid: true;', found unexpected identifier true", error.message);
-    assert_eq!(10, error.line);
-    assert_eq!(9, error.column);
+    assert_eq!("Unsupported property declaration: 'invalid: true;', \
+                Custom(UnknownProperty(\"invalid\"))", error.message);
+    assert_eq!(9, error.line);
+    assert_eq!(8, error.column);
 
     let error = errors.pop().unwrap();
     assert_eq!("Unsupported property declaration: 'display: invalid;', \
-                Custom(PropertyDeclaration(InvalidValue))", error.message);
-    assert_eq!(9, error.line);
-    assert_eq!(9, error.column);
+                Custom(PropertyDeclaration(InvalidValue(\"display\")))", error.message);
+    assert_eq!(8, error.line);
+    assert_eq!(8, error.column);
 
     // testing for the url
     assert_eq!(url, error.url);
diff --git a/tests/unit/stylo/Cargo.toml b/tests/unit/stylo/Cargo.toml
index 52dc50ea132..7034f9cbbe1 100644
--- a/tests/unit/stylo/Cargo.toml
+++ b/tests/unit/stylo/Cargo.toml
@@ -16,7 +16,7 @@ testing = ["style/testing"]
 
 [dependencies]
 atomic_refcell = "0.1"
-cssparser = "0.16.1"
+cssparser = "0.17.0"
 env_logger = "0.4"
 euclid = "0.15"
 geckoservo = {path = "../../../ports/geckolib"}