diff --git a/components/style/properties/longhands/position.mako.rs b/components/style/properties/longhands/position.mako.rs
index c5e507da10e6..53a3acf81ec1 100644
--- a/components/style/properties/longhands/position.mako.rs
+++ b/components/style/properties/longhands/position.mako.rs
@@ -244,21 +244,12 @@ ${helpers.predefined_type(
         if logical:
             spec = "https://drafts.csswg.org/css-logical-props/#propdef-%s"
     %>
-    // NOTE: Block-size doesn't support -moz-*-content keywords, since they make
-    // no sense on the block axis, but it simplifies things the have that it has
-    // the same type as the other properties, since otherwise we'd need to
-    // handle logical props where the types are different, which looks like a
-    // pain.
     % if product == "gecko":
-        <%
-            parse_function = "parse" if size != "block-size" else "parse_disallow_keyword"
-        %>
         // width, height, block-size, inline-size
         ${helpers.predefined_type(
             size,
             "MozLength",
             "computed::MozLength::auto()",
-            parse_function,
             logical=logical,
             logical_group="size",
             allow_quirks=not logical,
@@ -272,7 +263,6 @@ ${helpers.predefined_type(
             "min-%s" % size,
             "MozLength",
             "computed::MozLength::auto()",
-            parse_function,
             logical=logical,
             logical_group="min-size",
             allow_quirks=not logical,
@@ -284,7 +274,6 @@ ${helpers.predefined_type(
             "max-%s" % size,
             "MaxLength",
             "computed::MaxLength::none()",
-            parse_function,
             logical=logical,
             logical_group="max-size",
             allow_quirks=not logical,
diff --git a/components/style/values/specified/length.rs b/components/style/values/specified/length.rs
index db5a359cacdb..dce643a754f2 100644
--- a/components/style/values/specified/length.rs
+++ b/components/style/values/specified/length.rs
@@ -1256,17 +1256,6 @@ impl Parse for MozLength {
 }
 
 impl MozLength {
-    /// Parses, without quirks, and disallowing ExtremumLength values.
-    ///
-    /// Used for logical props in the block direction.
-    pub fn parse_disallow_keyword<'i, 't>(
-        context: &ParserContext,
-        input: &mut Parser<'i, 't>,
-    ) -> Result<Self, ParseError<'i>> {
-        let length = LengthOrPercentageOrAuto::parse_non_negative(context, input)?;
-        Ok(GenericMozLength::LengthOrPercentageOrAuto(length))
-    }
-
     /// Parses, with quirks.
     pub fn parse_quirky<'i, 't>(
         context: &ParserContext,
@@ -1308,17 +1297,6 @@ impl Parse for MaxLength {
 }
 
 impl MaxLength {
-    /// Parses, without quirks, and disallowing ExtremumLength values.
-    ///
-    /// Used for logical props in the block direction.
-    pub fn parse_disallow_keyword<'i, 't>(
-        context: &ParserContext,
-        input: &mut Parser<'i, 't>,
-    ) -> Result<Self, ParseError<'i>> {
-        let length = LengthOrPercentageOrNone::parse_non_negative(context, input)?;
-        Ok(GenericMaxLength::LengthOrPercentageOrNone(length))
-    }
-
     /// Parses, with quirks.
     pub fn parse_quirky<'i, 't>(
         context: &ParserContext,