Bug 1463978 - Don't generate catch-all branch if a image layer keyword value is exhaustive. r=emilio

MozReview-Commit-ID: H8T9Low6kqY

--HG--
extra : rebase_source : 98506d3c01df27c4fd408c1f01de040dd17df350

servo/components/style/properties/gecko.mako.rs

@@ -3805,7 +3805,9 @@ fn static_assert() {
                         % endif
                             => Keyword::${to_camel_case(value)},
                         % endfor
+                        % if keyword.gecko_inexhaustive:
                         _ => panic!("Found unexpected value in style struct for ${ident} property"),
+                        % endif
                     }
                 }).collect()
         )

servo/components/style/properties/longhand/background.mako.rs

@@ -60,22 +60,28 @@ ${helpers.single_keyword("background-attachment",
                          animation_value_type="discrete",
                          flags="APPLIES_TO_FIRST_LETTER APPLIES_TO_FIRST_LINE APPLIES_TO_PLACEHOLDER")}
 
-${helpers.single_keyword("background-clip",
-                         "border-box padding-box content-box",
-                         extra_gecko_values="text",
-                         vector=True, extra_prefixes="webkit",
-                         gecko_enum_prefix="StyleGeometryBox",
-                         spec="https://drafts.csswg.org/css-backgrounds/#the-background-clip",
-                         animation_value_type="discrete",
-                         flags="APPLIES_TO_FIRST_LETTER APPLIES_TO_FIRST_LINE APPLIES_TO_PLACEHOLDER")}
+${helpers.single_keyword(
+    "background-clip",
+    "border-box padding-box content-box",
+    extra_gecko_values="text",
+    vector=True, extra_prefixes="webkit",
+    gecko_enum_prefix="StyleGeometryBox",
+    gecko_inexhaustive=True,
+    spec="https://drafts.csswg.org/css-backgrounds/#the-background-clip",
+    animation_value_type="discrete",
+    flags="APPLIES_TO_FIRST_LETTER APPLIES_TO_FIRST_LINE APPLIES_TO_PLACEHOLDER",
+)}
 
-${helpers.single_keyword("background-origin",
-                         "padding-box border-box content-box",
-                         vector=True, extra_prefixes="webkit",
-                         gecko_enum_prefix="StyleGeometryBox",
-                         spec="https://drafts.csswg.org/css-backgrounds/#the-background-origin",
-                         animation_value_type="discrete",
-                         flags="APPLIES_TO_FIRST_LETTER APPLIES_TO_FIRST_LINE APPLIES_TO_PLACEHOLDER")}
+${helpers.single_keyword(
+    "background-origin",
+    "padding-box border-box content-box",
+    vector=True, extra_prefixes="webkit",
+    gecko_enum_prefix="StyleGeometryBox",
+    gecko_inexhaustive=True,
+    spec="https://drafts.csswg.org/css-backgrounds/#the-background-origin",
+    animation_value_type="discrete",
+    flags="APPLIES_TO_FIRST_LETTER APPLIES_TO_FIRST_LINE APPLIES_TO_PLACEHOLDER"
+)}
 
 ${helpers.predefined_type(
     "background-size",

servo/components/style/properties/longhand/svg.mako.rs

@@ -108,25 +108,32 @@ ${helpers.predefined_type(
     )}
 % endfor
 
-${helpers.single_keyword("mask-clip",
-                         "border-box content-box padding-box",
-                         extra_gecko_values="fill-box stroke-box view-box no-clip",
-                         vector=True,
-                         products="gecko",
-                         extra_prefixes="webkit",
-                         gecko_enum_prefix="StyleGeometryBox",
-                         animation_value_type="discrete",
-                         spec="https://drafts.fxtf.org/css-masking/#propdef-mask-clip")}
+${helpers.single_keyword(
+    "mask-clip",
+    "border-box content-box padding-box",
+    extra_gecko_values="fill-box stroke-box view-box no-clip",
+    vector=True,
+    products="gecko",
+    extra_prefixes="webkit",
+    gecko_enum_prefix="StyleGeometryBox",
+    gecko_inexhaustive=True,
+    animation_value_type="discrete",
+    spec="https://drafts.fxtf.org/css-masking/#propdef-mask-clip",
+)}
+
+${helpers.single_keyword(
+    "mask-origin",
+    "border-box content-box padding-box",
+    extra_gecko_values="fill-box stroke-box view-box",
+    vector=True,
+    products="gecko",
+    extra_prefixes="webkit",
+    gecko_enum_prefix="StyleGeometryBox",
+    gecko_inexhaustive=True,
+    animation_value_type="discrete",
+    spec="https://drafts.fxtf.org/css-masking/#propdef-mask-origin",
+)}
 
-${helpers.single_keyword("mask-origin",
-                         "border-box content-box padding-box",
-                         extra_gecko_values="fill-box stroke-box view-box",
-                         vector=True,
-                         products="gecko",
-                         extra_prefixes="webkit",
-                         gecko_enum_prefix="StyleGeometryBox",
-                         animation_value_type="discrete",
-                         spec="https://drafts.fxtf.org/css-masking/#propdef-mask-origin")}
 ${helpers.predefined_type(
     "mask-size",
     "background::BackgroundSize",