--- a/gfx/wr/webrender/res/cs_border_solid.glsl
+++ b/gfx/wr/webrender/res/cs_border_solid.glsl
@@ -47,18 +47,18 @@ varying vec2 vPos;
 
 in vec2 aTaskOrigin;
 in vec4 aRect;
 in vec4 aColor0;
 in vec4 aColor1;
 in int aFlags;
 in vec2 aWidths;
 in vec2 aRadii;
-in vec4 aHorizontallyAdjacentCorner;
-in vec4 aVerticallyAdjacentCorner;
+in vec4 aClipParams1;
+in vec4 aClipParams2;
 
 vec2 get_outer_corner_scale(int segment) {
     vec2 p;
 
     switch (segment) {
         case SEGMENT_TOP_LEFT:
             p = vec2(0.0, 0.0);
             break;
@@ -107,26 +107,26 @@ void main(void) {
 
     vColor0 = aColor0;
     vColor1 = aColor1;
     vClipCenter_Sign = vec4(outer + clip_sign * aRadii, clip_sign);
     vClipRadii = vec4(aRadii, max(aRadii - aWidths, 0.0));
     vColorLine = vec4(outer, aWidths.y * -clip_sign.y, aWidths.x * clip_sign.x);
 
     vec2 horizontal_clip_sign = vec2(-clip_sign.x, clip_sign.y);
-    vHorizontalClipCenter_Sign = vec4(aHorizontallyAdjacentCorner.xy +
-                                      horizontal_clip_sign * aHorizontallyAdjacentCorner.zw,
+    vHorizontalClipCenter_Sign = vec4(aClipParams1.xy +
+                                      horizontal_clip_sign * aClipParams1.zw,
                                       horizontal_clip_sign);
-    vHorizontalClipRadii = aHorizontallyAdjacentCorner.zw;
+    vHorizontalClipRadii = aClipParams1.zw;
 
     vec2 vertical_clip_sign = vec2(clip_sign.x, -clip_sign.y);
-    vVerticalClipCenter_Sign = vec4(aVerticallyAdjacentCorner.xy +
-                                    vertical_clip_sign * aVerticallyAdjacentCorner.zw,
+    vVerticalClipCenter_Sign = vec4(aClipParams2.xy +
+                                    vertical_clip_sign * aClipParams2.zw,
                                     vertical_clip_sign);
-    vVerticalClipRadii = aVerticallyAdjacentCorner.zw;
+    vVerticalClipRadii = aClipParams2.zw;
 
     gl_Position = uTransform * vec4(aTaskOrigin + aRect.xy + vPos, 0.0, 1.0);
 }
 #endif
 
 #ifdef WR_FRAGMENT_SHADER
 void main(void) {
     float aa_range = compute_aa_range(vPos);

--- a/gfx/wr/webrender/src/device/gl.rs
+++ b/gfx/wr/webrender/src/device/gl.rs
@@ -1965,16 +1965,34 @@ impl Device {
 
             if self.cached_programs.is_some() {
                 self.gl.program_parameter_i(program.id, gl::PROGRAM_BINARY_RETRIEVABLE_HINT, gl::TRUE as gl::GLint);
             }
 
             // Link!
             self.gl.link_program(program.id);
 
+            if cfg!(debug_assertions) {
+                // Check that all our overrides worked
+                for (i, attr) in descriptor
+                    .vertex_attributes
+                    .iter()
+                    .chain(descriptor.instance_attributes.iter())
+                    .enumerate()
+                {
+                    //Note: we can't assert here because the driver may optimize out some of the
+                    // vertex attributes legitimately, returning their location to be -1.
+                    let location = self.gl.get_attrib_location(program.id, attr.name);
+                    if location != i as gl::GLint {
+                        warn!("Attribute {:?} is not found in the shader {}. Expected at {}, found at {}",
+                            attr, program.source_info.base_filename, i, location);
+                    }
+                }
+            }
+
             // GL recommends detaching and deleting shaders once the link
             // is complete (whether successful or not). This allows the driver
             // to free any memory associated with the parsing and compilation.
             self.gl.detach_shader(program.id, vs_id);
             self.gl.detach_shader(program.id, fs_id);
             self.gl.delete_shader(vs_id);
             self.gl.delete_shader(fs_id);