Bug 1360557. Fix the Web IDL parser to report more useful errors when extended attributes are used on constructs that don't allow them. r=qdot

dom/bindings/parser/WebIDL.py

@@ -573,7 +573,10 @@ class IDLExternalInterface(IDLObjectWithIdentifier, IDLExposureMixins):
         return False
 
     def addExtendedAttributes(self, attrs):
-        assert len(attrs) == 0
+        if len(attrs) != 0:
+            raise WebIDLError("There are no extended attributes that are "
+                              "allowed on external interfaces",
+                              [attrs[0].location, self.location])
 
     def resolve(self, parentScope):
         pass
@@ -1932,7 +1935,10 @@ class IDLDictionary(IDLObjectWithScope):
                                   [member.location] + locations)
 
     def addExtendedAttributes(self, attrs):
-        assert len(attrs) == 0
+        if len(attrs) != 0:
+            raise WebIDLError("There are no extended attributes that are "
+                              "allowed on dictionaries",
+                              [attrs[0].location, self.location])
 
     def _getDependentObjects(self):
         deps = set(self.members)
@@ -1966,7 +1972,10 @@ class IDLEnum(IDLObjectWithIdentifier):
         return True
 
     def addExtendedAttributes(self, attrs):
-        assert len(attrs) == 0
+        if len(attrs) != 0:
+            raise WebIDLError("There are no extended attributes that are "
+                              "allowed on enums",
+                              [attrs[0].location, self.location])
 
     def _getDependentObjects(self):
         return set()
@@ -2139,7 +2148,11 @@ class IDLType(IDLObject):
         return self.nullable() and self.inner.callback._treatNonObjectAsNull
 
     def addExtendedAttributes(self, attrs):
-        assert len(attrs) == 0
+        if len(attrs) != 0:
+            raise WebIDLError("There are no extended attributes that are "
+                              "allowed on types, for now (but this is "
+                              "changing; see bug 1359269)",
+                              [attrs[0].location, self.location])
 
     def resolveType(self, parentScope):
         pass
@@ -2707,7 +2720,10 @@ class IDLTypedef(IDLObjectWithIdentifier):
         return True
 
     def addExtendedAttributes(self, attrs):
-        assert len(attrs) == 0
+        if len(attrs) != 0:
+            raise WebIDLError("There are no extended attributes that are "
+                              "allowed on typedefs",
+                              [attrs[0].location, self.location])
 
     def _getDependentObjects(self):
         return self.innerType._getDependentObjects()
@@ -5108,7 +5124,10 @@ class IDLImplementsStatement(IDLObject):
         pass
 
     def addExtendedAttributes(self, attrs):
-        assert len(attrs) == 0
+        if len(attrs) != 0:
+            raise WebIDLError("There are no extended attributes that are "
+                              "allowed on implements statements",
+                              [attrs[0].location, self.location])
 
 
 class IDLExtendedAttribute(IDLObject):