From 48bb508f667a2de4e1107fa3e5574892aa321620 Mon Sep 17 00:00:00 2001
From: Alon Levy <alon@pobox.com>
Date: Sun, 12 Feb 2017 06:49:01 +0200
Subject: [PATCH] fix #15492

---
 components/style/values/specified/basic_shape.rs | 4 ++--
 tests/unit/style/parsing/basic_shape.rs          | 3 +++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/components/style/values/specified/basic_shape.rs b/components/style/values/specified/basic_shape.rs
index 7f77337218c..3d6399cefc5 100644
--- a/components/style/values/specified/basic_shape.rs
+++ b/components/style/values/specified/basic_shape.rs
@@ -662,8 +662,8 @@ impl Default for ShapeRadius {
 }
 
 impl Parse for ShapeRadius {
-    fn parse(context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
-        input.try(|i| LengthOrPercentage::parse(context, i)).map(ShapeRadius::Length).or_else(|_| {
+    fn parse(_: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
+        input.try(|i| LengthOrPercentage::parse_non_negative(i)).map(ShapeRadius::Length).or_else(|_| {
             match_ignore_ascii_case! { try!(input.expect_ident()),
                 "closest-side" => Ok(ShapeRadius::ClosestSide),
                 "farthest-side" => Ok(ShapeRadius::FarthestSide),
diff --git a/tests/unit/style/parsing/basic_shape.rs b/tests/unit/style/parsing/basic_shape.rs
index 342d732b5c2..ecac5679980 100644
--- a/tests/unit/style/parsing/basic_shape.rs
+++ b/tests/unit/style/parsing/basic_shape.rs
@@ -96,6 +96,8 @@ fn test_circle() {
     assert_roundtrip_basicshape!(Circle::parse, "circle(closest-side at center)", "circle(at 50% 50%)");
     assert_roundtrip_basicshape!(Circle::parse, "circle(farthest-side at center)",
                                                 "circle(farthest-side at 50% 50%)");
+    assert_roundtrip_basicshape!(Circle::parse, "circle(10px)",
+                                                "circle(10px at 50% 50%)");
     assert_roundtrip_basicshape!(Circle::parse, "circle(20px at center)", "circle(20px at 50% 50%)");
     assert_roundtrip_basicshape!(Circle::parse, "circle(calc(1px + 50%) at center)",
                                                 "circle(calc(1px + 50%) at 50% 50%)");
@@ -114,6 +116,7 @@ fn test_circle() {
                                                 "circle(at left 5% bottom 1px)");
 
     assert!(parse(Circle::parse, "circle(at top 40%)").is_err());
+    assert!(parse(Circle::parse, "circle(-10px)").is_err());
 }
 
 #[test]