diff --git a/dom/base/Link.cpp b/dom/base/Link.cpp
index 1f2c381a0a2a..af8e4d38def2 100644
--- a/dom/base/Link.cpp
+++ b/dom/base/Link.cpp
@@ -139,10 +139,19 @@ void Link::SetProtocol(const nsAString& aProtocol) {
     // Ignore failures to be compatible with NS4.
     return;
   }
-  uri = net::TryChangeProtocol(uri, aProtocol);
-  if (!uri) {
+
+  nsAString::const_iterator start, end;
+  aProtocol.BeginReading(start);
+  aProtocol.EndReading(end);
+  nsAString::const_iterator iter(start);
+  (void)FindCharInReadable(':', iter, end);
+  nsresult rv = NS_MutateURI(uri)
+                    .SetScheme(NS_ConvertUTF16toUTF8(Substring(start, iter)))
+                    .Finalize(uri);
+  if (NS_FAILED(rv)) {
     return;
   }
+
   SetHrefAttribute(uri);
 }
 
diff --git a/dom/url/URL.cpp b/dom/url/URL.cpp
index 799bb72cffbb..933ebc91c5ea 100644
--- a/dom/url/URL.cpp
+++ b/dom/url/URL.cpp
@@ -233,14 +233,38 @@ void URL::GetProtocol(nsAString& aProtocol) const {
 }
 
 void URL::SetProtocol(const nsAString& aProtocol) {
-  nsCOMPtr<nsIURI> uri(URI());
-  if (!uri) {
+  nsAString::const_iterator start;
+  aProtocol.BeginReading(start);
+
+  nsAString::const_iterator end;
+  aProtocol.EndReading(end);
+
+  nsAString::const_iterator iter(start);
+  FindCharInReadable(':', iter, end);
+
+  // Changing the protocol of a URL, changes the "nature" of the URI
+  // implementation. In order to do this properly, we have to serialize the
+  // existing URL and reparse it in a new object.
+  nsCOMPtr<nsIURI> clone;
+  nsresult rv = NS_MutateURI(URI())
+                    .SetScheme(NS_ConvertUTF16toUTF8(Substring(start, iter)))
+                    .Finalize(clone);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
     return;
   }
-  uri = net::TryChangeProtocol(uri, aProtocol);
-  if (!uri) {
+
+  nsAutoCString href;
+  rv = clone->GetSpec(href);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
     return;
   }
+
+  nsCOMPtr<nsIURI> uri;
+  rv = NS_NewURI(getter_AddRefs(uri), href);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return;
+  }
+
   mURI = std::move(uri);
 }
 
diff --git a/dom/url/tests/test_url.html b/dom/url/tests/test_url.html
index 0882e01834f2..85f39e54b9f9 100644
--- a/dom/url/tests/test_url.html
+++ b/dom/url/tests/test_url.html
@@ -193,7 +193,6 @@
       base: undefined,
       error: false,
       protocol: "gopher:",
-      expectedChangedProtocol: "https:",
     },
     { url: "ws://ws.something.net",
       base: undefined,
@@ -209,7 +208,6 @@
       base: undefined,
       error: false,
       protocol: "foo:",
-      expectedChangedProtocol: "https:",
     },
 
     { url: "about:blank",
@@ -321,8 +319,7 @@
 
     if ("href" in test) is(url.href, test.href, "href");
     if ("origin" in test) is(url.origin, test.origin, "origin");
-    if ("expectedChangedProtocol" in test) is(url.protocol, test.expectedChangedProtocol, "protocol");
-    else if ("protocol" in test) is(url.protocol, test.protocol, "protocol");
+    if ("protocol" in test) is(url.protocol, test.protocol, "protocol");
     if ("username" in test) is(url.username, test.username, "username");
     if ("password" in test) is(url.password, test.password, "password");
     if ("host" in test) is(url.host, test.host, "host");
diff --git a/dom/url/tests/test_url_data.html b/dom/url/tests/test_url_data.html
index beeb7a2d3983..a4d017936a66 100644
--- a/dom/url/tests/test_url_data.html
+++ b/dom/url/tests/test_url_data.html
@@ -32,12 +32,12 @@ try {
 }
 
 base.protocol = "http:";
-ok(true, "Protocol: http not changed (special scheme)");
-is(base.href, "chrome://text/plain,", "Base URL is correct");
+ok(true, "Protocol: http changed");
+is(base.href, "http://text/plain,", "Base URL is correct");
 
 relative = new URL("a", base);
 ok(relative, "This works.");
-is(relative.href, "chrome://text/a", "Relative URL is correct");
+is(relative.href, "http://text/a", "Relative URL is correct");
 
 </script>
 
diff --git a/dom/url/tests/urlApi_worker.js b/dom/url/tests/urlApi_worker.js
index 5a969c8e4cae..40243c1e6686 100644
--- a/dom/url/tests/urlApi_worker.js
+++ b/dom/url/tests/urlApi_worker.js
@@ -202,7 +202,6 @@ onmessage = function () {
       base: undefined,
       error: false,
       protocol: "gopher:",
-      expectedChangedProtocol: "https:",
     },
     {
       url: "ws://ws.something.net",
@@ -221,7 +220,6 @@ onmessage = function () {
       base: undefined,
       error: false,
       protocol: "foo:",
-      expectedChangedProtocol: "https:",
     },
   ];
 
@@ -319,9 +317,7 @@ onmessage = function () {
     if ("origin" in test) {
       is(url.origin, test.origin, "origin");
     }
-    if ("expectedChangedProtocol" in test) {
-      is(url.protocol, test.expectedChangedProtocol, "protocol");
-    } else if ("protocol" in test) {
+    if ("protocol" in test) {
       is(url.protocol, test.protocol, "protocol");
     }
     if ("username" in test) {
diff --git a/netwerk/base/nsNetUtil.cpp b/netwerk/base/nsNetUtil.cpp
index 2244f90e9f41..f932e64e8001 100644
--- a/netwerk/base/nsNetUtil.cpp
+++ b/netwerk/base/nsNetUtil.cpp
@@ -3363,102 +3363,6 @@ bool SchemeIsFTP(nsIURI* aURI) {
   return aURI->SchemeIs("ftp");
 }
 
-bool SchemeIsSpecial(const nsACString& aScheme) {
-  // See https://url.spec.whatwg.org/#special-scheme
-  return aScheme.EqualsIgnoreCase("ftp") || aScheme.EqualsIgnoreCase("file") ||
-         aScheme.EqualsIgnoreCase("http") ||
-         aScheme.EqualsIgnoreCase("https") || aScheme.EqualsIgnoreCase("ws") ||
-         aScheme.EqualsIgnoreCase("wss");
-}
-
-bool IsSchemeChangePermitted(nsIURI* aOldURI, const nsACString& newScheme) {
-  // See step 2.1 in https://url.spec.whatwg.org/#special-scheme
-  // Note: The spec text uses "buffer" instead of newScheme, and "url"
-  MOZ_ASSERT(aOldURI);
-
-  nsAutoCString tmp;
-  nsresult rv = aOldURI->GetScheme(tmp);
-  // If url's scheme is a special scheme and buffer is not a
-  // special scheme, then return.
-  // If url's scheme is not a special scheme and buffer is a
-  // special scheme, then return.
-  if (NS_FAILED(rv) || SchemeIsSpecial(tmp) != SchemeIsSpecial(newScheme)) {
-    return false;
-  }
-
-  // If url's scheme is "file" and its host is an empty host, then return.
-  if (aOldURI->SchemeIs("file")) {
-    rv = aOldURI->GetHost(tmp);
-    if (NS_FAILED(rv) || tmp.IsEmpty()) {
-      return false;
-    }
-  }
-
-  // URL Spec: If url includes credentials or has a non-null port, and
-  // buffer is "file", then return.
-  if (newScheme.EqualsIgnoreCase("file")) {
-    rv = aOldURI->GetUsername(tmp);
-    if (NS_FAILED(rv) || !tmp.IsEmpty()) {
-      return false;
-    }
-    rv = aOldURI->GetPassword(tmp);
-    if (NS_FAILED(rv) || !tmp.IsEmpty()) {
-      return false;
-    }
-    int32_t port;
-    rv = aOldURI->GetPort(&port);
-    if (NS_FAILED(rv) || port != -1) {
-      return false;
-    }
-  }
-
-  return true;
-}
-
-already_AddRefed<nsIURI> TryChangeProtocol(nsIURI* aURI,
-                                           const nsAString& aProtocol) {
-  MOZ_ASSERT(aURI);
-
-  nsAString::const_iterator start;
-  aProtocol.BeginReading(start);
-
-  nsAString::const_iterator end;
-  aProtocol.EndReading(end);
-
-  nsAString::const_iterator iter(start);
-  FindCharInReadable(':', iter, end);
-
-  // Changing the protocol of a URL, changes the "nature" of the URI
-  // implementation. In order to do this properly, we have to serialize the
-  // existing URL and reparse it in a new object.
-  nsCOMPtr<nsIURI> clone;
-  nsresult rv = NS_MutateURI(aURI)
-                    .SetScheme(NS_ConvertUTF16toUTF8(Substring(start, iter)))
-                    .Finalize(clone);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return nullptr;
-  }
-
-  nsAutoCString newScheme;
-  rv = clone->GetScheme(newScheme);
-  if (NS_FAILED(rv) || !net::IsSchemeChangePermitted(aURI, newScheme)) {
-    return nullptr;
-  }
-
-  nsAutoCString href;
-  rv = clone->GetSpec(href);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return nullptr;
-  }
-
-  RefPtr<nsIURI> uri;
-  rv = NS_NewURI(getter_AddRefs(uri), href);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return nullptr;
-  }
-  return uri.forget();
-}
-
 // Decode a parameter value using the encoding defined in RFC 5987 (in place)
 //
 //   charset  "'" [ language ] "'" value-chars
diff --git a/netwerk/base/nsNetUtil.h b/netwerk/base/nsNetUtil.h
index 97839891105c..65a8033769d0 100644
--- a/netwerk/base/nsNetUtil.h
+++ b/netwerk/base/nsNetUtil.h
@@ -1016,12 +1016,6 @@ bool SchemeIsViewSource(nsIURI* aURI);
 bool SchemeIsResource(nsIURI* aURI);
 bool SchemeIsFTP(nsIURI* aURI);
 
-// Helper functions for SetProtocol methods to follow
-// step 2.1 in https://url.spec.whatwg.org/#scheme-state
-bool SchemeIsSpecial(const nsACString&);
-bool IsSchemeChangePermitted(nsIURI*, const nsACString&);
-already_AddRefed<nsIURI> TryChangeProtocol(nsIURI*, const nsAString&);
-
 struct LinkHeader {
   nsString mHref;
   nsString mRel;
diff --git a/testing/web-platform/meta/url/url-setters-a-area.window.js.ini b/testing/web-platform/meta/url/url-setters-a-area.window.js.ini
index 6a6b66d5c52b..c1a1ce1158e8 100644
--- a/testing/web-platform/meta/url/url-setters-a-area.window.js.ini
+++ b/testing/web-platform/meta/url/url-setters-a-area.window.js.ini
@@ -1,4 +1,592 @@
+[url-setters-a-area.window.html]
+  expected:
+    if (os == "android") and fission: [OK, TIMEOUT]
+  [<a>: Setting <http://test@example.net>.protocol = 'file' Can’t switch from URL containing username/password/port to file]
+    expected: FAIL
+
+  [<area>: Setting <http://test@example.net>.protocol = 'file' Can’t switch from URL containing username/password/port to file]
+    expected: FAIL
+
+  [<a>: Setting <https://example.net:1234>.protocol = 'file']
+    expected: FAIL
+
+  [<area>: Setting <https://example.net:1234>.protocol = 'file']
+    expected: FAIL
+
+  [<a>: Setting <wss://x:x@example.net:1234>.protocol = 'file']
+    expected: FAIL
+
+  [<area>: Setting <wss://x:x@example.net:1234>.protocol = 'file']
+    expected: FAIL
+
+  [<a>: Setting <file://localhost/>.protocol = 'http' Can’t switch from file URL with no host]
+    expected: FAIL
+
+  [<area>: Setting <file://localhost/>.protocol = 'http' Can’t switch from file URL with no host]
+    expected: FAIL
+
+  [<a>: Setting <file:///test>.protocol = 'https']
+    expected: FAIL
+
+  [<area>: Setting <file:///test>.protocol = 'https']
+    expected: FAIL
+
+  [<a>: Setting <file:>.protocol = 'wss']
+    expected: FAIL
+
+  [<area>: Setting <file:>.protocol = 'wss']
+    expected: FAIL
+
+  [<a>: Setting <http://example.net>.protocol = 'b' Can’t switch from special scheme to non-special]
+    expected: FAIL
+
+  [<area>: Setting <http://example.net>.protocol = 'b' Can’t switch from special scheme to non-special]
+    expected: FAIL
+
+  [<a>: Setting <file://hi/path>.protocol = 's']
+    expected: FAIL
+
+  [<area>: Setting <file://hi/path>.protocol = 's']
+    expected: FAIL
+
+  [<a>: Setting <https://example.net>.protocol = 's']
+    expected: FAIL
+
+  [<area>: Setting <https://example.net>.protocol = 's']
+    expected: FAIL
+
+  [<a>: Setting <ftp://example.net>.protocol = 'test']
+    expected: FAIL
+
+  [<area>: Setting <ftp://example.net>.protocol = 'test']
+    expected: FAIL
+
+  [<a>: Setting <mailto:me@example.net>.protocol = 'http' Cannot-be-a-base URL doesn’t have a host, but URL in a special scheme must.]
+    expected: FAIL
+
+  [<area>: Setting <mailto:me@example.net>.protocol = 'http' Cannot-be-a-base URL doesn’t have a host, but URL in a special scheme must.]
+    expected: FAIL
+
+  [<a>: Setting <ssh://me@example.net>.protocol = 'http' Can’t switch from non-special scheme to special]
+    expected: FAIL
+
+  [<area>: Setting <ssh://me@example.net>.protocol = 'http' Can’t switch from non-special scheme to special]
+    expected: FAIL
+
+  [<a>: Setting <ssh://me@example.net>.protocol = 'https']
+    expected: FAIL
+
+  [<area>: Setting <ssh://me@example.net>.protocol = 'https']
+    expected: FAIL
+
+  [<a>: Setting <ssh://me@example.net>.protocol = 'file']
+    expected: FAIL
+
+  [<area>: Setting <ssh://me@example.net>.protocol = 'file']
+    expected: FAIL
+
+  [<a>: Setting <ssh://example.net>.protocol = 'file']
+    expected: FAIL
+
+  [<area>: Setting <ssh://example.net>.protocol = 'file']
+    expected: FAIL
+
+  [<a>: Setting <nonsense:///test>.protocol = 'https']
+    expected: FAIL
+
+  [<area>: Setting <nonsense:///test>.protocol = 'https']
+    expected: FAIL
+
+  [<a>: Setting <http://example.net>.username = '\x00\x01\t\n\r\x1f !"#$%&'()*+,-./09:;<=>?@AZ[\\\]^_`az{|}~€Éé' UTF-8 percent encoding with the userinfo encode set.]
+    expected: FAIL
+
+  [<area>: Setting <http://example.net>.username = '\x00\x01\t\n\r\x1f !"#$%&'()*+,-./09:;<=>?@AZ[\\\]^_`az{|}~€Éé' UTF-8 percent encoding with the userinfo encode set.]
+    expected: FAIL
+
+  [<a>: Setting <javascript://x/>.username = 'wario']
+    expected: FAIL
+
+  [<area>: Setting <javascript://x/>.username = 'wario']
+    expected: FAIL
+
+  [<a>: Setting <file://test/>.username = 'test']
+    expected: FAIL
+
+  [<area>: Setting <file://test/>.username = 'test']
+    expected: FAIL
+
+  [<a>: Setting <http://example.net>.password = '\x00\x01\t\n\r\x1f !"#$%&'()*+,-./09:;<=>?@AZ[\\\]^_`az{|}~€Éé' UTF-8 percent encoding with the userinfo encode set.]
+    expected: FAIL
+
+  [<area>: Setting <http://example.net>.password = '\x00\x01\t\n\r\x1f !"#$%&'()*+,-./09:;<=>?@AZ[\\\]^_`az{|}~€Éé' UTF-8 percent encoding with the userinfo encode set.]
+    expected: FAIL
+
+  [<a>: Setting <javascript://x/>.password = 'bowser']
+    expected: FAIL
+
+  [<area>: Setting <javascript://x/>.password = 'bowser']
+    expected: FAIL
+
+  [<a>: Setting <file://test/>.password = 'test']
+    expected: FAIL
+
+  [<area>: Setting <file://test/>.password = 'test']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.host = '\x00' Non-special scheme]
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.host = '\x00' Non-special scheme]
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.host = '\t']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.host = '\t']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.host = '\n']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.host = '\n']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.host = '\r']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.host = '\r']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.host = ' ']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.host = ' ']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.host = '#']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.host = '#']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.host = '/']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.host = '/']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.host = '?']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.host = '?']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.host = '@']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.host = '@']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.host = 'ß']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.host = 'ß']
+    expected: FAIL
+
+  [<a>: Setting <view-source+http://example.net/foo>.host = '' The empty host is OK for non-special schemes]
+    expected: FAIL
+
+  [<area>: Setting <view-source+http://example.net/foo>.host = '' The empty host is OK for non-special schemes]
+    expected: FAIL
+
+  [<a>: Setting <a:/foo>.host = 'example.net' Path-only URLs can gain a host]
+    expected: FAIL
+
+  [<area>: Setting <a:/foo>.host = 'example.net' Path-only URLs can gain a host]
+    expected: FAIL
+
+  [<a>: Setting <view-source+http://example.net/path>.host = 'example.com\\stuff' \\ is not a delimiter for non-special schemes, but still forbidden in hosts]
+    expected: FAIL
+
+  [<area>: Setting <view-source+http://example.net/path>.host = 'example.com\\stuff' \\ is not a delimiter for non-special schemes, but still forbidden in hosts]
+    expected: FAIL
+
+  [<a>: Setting <view-source+http://example.net/path>.host = 'example.com:8080stuff2' Anything other than ASCII digit stops the port parser in a setter but is not an error]
+    expected: FAIL
+
+  [<area>: Setting <view-source+http://example.net/path>.host = 'example.com:8080stuff2' Anything other than ASCII digit stops the port parser in a setter but is not an error]
+    expected: FAIL
+
+  [<a>: Setting <file://y/>.host = 'x:123']
+    expected: FAIL
+
+  [<area>: Setting <file://y/>.host = 'x:123']
+    expected: FAIL
+
+  [<a>: Setting <sc://test@test/>.host = '']
+    expected: FAIL
+
+  [<area>: Setting <sc://test@test/>.host = '']
+    expected: FAIL
+
+  [<a>: Setting <sc://test:12/>.host = '']
+    expected: FAIL
+
+  [<area>: Setting <sc://test:12/>.host = '']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.hostname = '\x00' Non-special scheme]
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.hostname = '\x00' Non-special scheme]
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.hostname = '\t']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.hostname = '\t']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.hostname = '\n']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.hostname = '\n']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.hostname = '\r']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.hostname = '\r']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.hostname = ' ']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.hostname = ' ']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.hostname = '#']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.hostname = '#']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.hostname = '/']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.hostname = '/']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.hostname = '?']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.hostname = '?']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.hostname = '@']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.hostname = '@']
+    expected: FAIL
+
+  [<a>: Setting <view-source+http://example.net/foo>.hostname = '' The empty host is OK for non-special schemes]
+    expected: FAIL
+
+  [<area>: Setting <view-source+http://example.net/foo>.hostname = '' The empty host is OK for non-special schemes]
+    expected: FAIL
+
+  [<a>: Setting <a:/foo>.hostname = 'example.net' Path-only URLs can gain a host]
+    expected: FAIL
+
+  [<area>: Setting <a:/foo>.hostname = 'example.net' Path-only URLs can gain a host]
+    expected: FAIL
+
+  [<a>: Setting <view-source+http://example.net/path>.hostname = 'example.com\\stuff' \\ is not a delimiter for non-special schemes, but still forbidden in hosts]
+    expected: FAIL
+
+  [<area>: Setting <view-source+http://example.net/path>.hostname = 'example.com\\stuff' \\ is not a delimiter for non-special schemes, but still forbidden in hosts]
+    expected: FAIL
+
+  [<a>: Setting <file://y/>.hostname = 'x:123']
+    expected: FAIL
+
+  [<area>: Setting <file://y/>.hostname = 'x:123']
+    expected: FAIL
+
+  [<a>: Setting <sc://test@test/>.hostname = '']
+    expected: FAIL
+
+  [<area>: Setting <sc://test@test/>.hostname = '']
+    expected: FAIL
+
+  [<a>: Setting <sc://test:12/>.hostname = '']
+    expected: FAIL
+
+  [<area>: Setting <sc://test:12/>.hostname = '']
+    expected: FAIL
+
+  [<a>: Setting <non-spec:/.//p>.hostname = 'h' Drop /. from path]
+    expected: FAIL
+
+  [<area>: Setting <non-spec:/.//p>.hostname = 'h' Drop /. from path]
+    expected: FAIL
+
+  [<a>: Setting <non-spec:/.//p>.hostname = '']
+    expected: FAIL
+
+  [<area>: Setting <non-spec:/.//p>.hostname = '']
+    expected: FAIL
+
+  [<a>: Setting <view-source+http://example.net/path>.port = '8080stuff2' Anything other than ASCII digit stops the port parser in a setter but is not an error]
+    expected: FAIL
+
+  [<area>: Setting <view-source+http://example.net/path>.port = '8080stuff2' Anything other than ASCII digit stops the port parser in a setter but is not an error]
+    expected: FAIL
+
+  [<a>: Setting <non-special://example.net:8080/path>.port = '65536' Port numbers are 16 bit integers, overflowing is an error]
+    expected: FAIL
+
+  [<area>: Setting <non-special://example.net:8080/path>.port = '65536' Port numbers are 16 bit integers, overflowing is an error]
+    expected: FAIL
+
+  [<a>: Setting <file://test/>.port = '12']
+    expected: FAIL
+
+  [<area>: Setting <file://test/>.port = '12']
+    expected: FAIL
+
+  [<a>: Setting <sc://x/>.port = '12']
+    expected: FAIL
+
+  [<area>: Setting <sc://x/>.port = '12']
+    expected: FAIL
+
+  [<a>: Setting <javascript://x/>.port = '12']
+    expected: FAIL
+
+  [<area>: Setting <javascript://x/>.port = '12']
+    expected: FAIL
+
+  [<a>: Setting <mailto:me@example.net>.pathname = '/foo' Cannot-be-a-base don’t have a path]
+    expected: FAIL
+
+  [<area>: Setting <mailto:me@example.net>.pathname = '/foo' Cannot-be-a-base don’t have a path]
+    expected: FAIL
+
+  [<a>: Setting <unix:/run/foo.socket?timeout=10>.pathname = '/var/log/../run/bar.socket']
+    expected: FAIL
+
+  [<area>: Setting <unix:/run/foo.socket?timeout=10>.pathname = '/var/log/../run/bar.socket']
+    expected: FAIL
+
+  [<a>: Setting <http://example.net/home?lang=fr#nav>.pathname = '\\a\\%2E\\b\\%2e.\\c' \\ is a segment delimiter for 'special' URLs]
+    expected: FAIL
+
+  [<area>: Setting <http://example.net/home?lang=fr#nav>.pathname = '\\a\\%2E\\b\\%2e.\\c' \\ is a segment delimiter for 'special' URLs]
+    expected: FAIL
+
+  [<a>: Setting <view-source+http://example.net/home?lang=fr#nav>.pathname = '\\a\\%2E\\b\\%2e.\\c' \\ is *not* a segment delimiter for non-'special' URLs]
+    expected: FAIL
+
+  [<area>: Setting <view-source+http://example.net/home?lang=fr#nav>.pathname = '\\a\\%2E\\b\\%2e.\\c' \\ is *not* a segment delimiter for non-'special' URLs]
+    expected: FAIL
+
+  [<a>: Setting <a:/>.pathname = '\x00\x01\t\n\r\x1f !"#$%&'()*+,-./09:;<=>?@AZ[\\\]^_`az{|}~€Éé' UTF-8 percent encoding with the default encode set. Tabs and newlines are removed.]
+    expected: FAIL
+
+  [<area>: Setting <a:/>.pathname = '\x00\x01\t\n\r\x1f !"#$%&'()*+,-./09:;<=>?@AZ[\\\]^_`az{|}~€Éé' UTF-8 percent encoding with the default encode set. Tabs and newlines are removed.]
+    expected: FAIL
+
+  [<a>: Setting <sc://example.net>.pathname = '?' ? needs to be encoded, non-special scheme]
+    expected: FAIL
+
+  [<area>: Setting <sc://example.net>.pathname = '?' ? needs to be encoded, non-special scheme]
+    expected: FAIL
+
+  [<a>: Setting <sc://example.net>.pathname = '#' # needs to be encoded, non-special scheme]
+    expected: FAIL
+
+  [<area>: Setting <sc://example.net>.pathname = '#' # needs to be encoded, non-special scheme]
+    expected: FAIL
+
+  [<a>: Setting <file://monkey/>.pathname = '\\\\' File URLs and (back)slashes]
+    expected: FAIL
+
+  [<area>: Setting <file://monkey/>.pathname = '\\\\' File URLs and (back)slashes]
+    expected: FAIL
+
+  [<a>: Setting <file:///unicorn>.pathname = '//\\/' File URLs and (back)slashes]
+    expected: FAIL
+
+  [<area>: Setting <file:///unicorn>.pathname = '//\\/' File URLs and (back)slashes]
+    expected: FAIL
+
+  [<a>: Setting <non-spec:/>.pathname = '/.//p' Serialize /. in path]
+    expected: FAIL
+
+  [<area>: Setting <non-spec:/>.pathname = '/.//p' Serialize /. in path]
+    expected: FAIL
+
+  [<a>: Setting <non-spec:/>.pathname = '/..//p']
+    expected: FAIL
+
+  [<area>: Setting <non-spec:/>.pathname = '/..//p']
+    expected: FAIL
+
+  [<a>: Setting <non-spec:/>.pathname = '//p']
+    expected: FAIL
+
+  [<area>: Setting <non-spec:/>.pathname = '//p']
+    expected: FAIL
+
+  [<a>: Setting <non-spec:/.//>.pathname = 'p' Drop /. from path]
+    expected: FAIL
+
+  [<area>: Setting <non-spec:/.//>.pathname = 'p' Drop /. from path]
+    expected: FAIL
+
+  [<a>: Setting <a:/>.search = '\x00\x01\t\n\r\x1f !"#$%&'()*+,-./09:;<=>?@AZ[\\\]^_`az{|}~€Éé' UTF-8 percent encoding with the query encode set. Tabs and newlines are removed.]
+    expected: FAIL
+
+  [<area>: Setting <a:/>.search = '\x00\x01\t\n\r\x1f !"#$%&'()*+,-./09:;<=>?@AZ[\\\]^_`az{|}~€Éé' UTF-8 percent encoding with the query encode set. Tabs and newlines are removed.]
+    expected: FAIL
+
+  [<a>: Setting <a:/>.hash = '\x00\x01\t\n\r\x1f !"#$%&'()*+,-./09:;<=>?@AZ[\\\]^_`az{|}~€Éé' Simple percent-encoding; tabs and newlines are removed]
+    expected: FAIL
+
+  [<area>: Setting <a:/>.hash = '\x00\x01\t\n\r\x1f !"#$%&'()*+,-./09:;<=>?@AZ[\\\]^_`az{|}~€Éé' Simple percent-encoding; tabs and newlines are removed]
+    expected: FAIL
+
+  [<a>: Setting <sc://example.com/>.host = '///bad.com' Leading / is not stripped]
+    expected: FAIL
+
+  [<area>: Setting <sc://example.com/>.host = '///bad.com' Leading / is not stripped]
+    expected: FAIL
+
+  [<a>: Setting <sc://example.com/>.hostname = '///bad.com' Leading / is not stripped]
+    expected: FAIL
+
+  [<area>: Setting <sc://example.com/>.hostname = '///bad.com' Leading / is not stripped]
+    expected: FAIL
+
+  [<a>: Setting <foo://somehost/some/path>.pathname = '' Non-special URLs can have their paths erased]
+    expected: FAIL
+
+  [<area>: Setting <foo://somehost/some/path>.pathname = '' Non-special URLs can have their paths erased]
+    expected: FAIL
+
+  [<a>: Setting <foo:///some/path>.pathname = '' Non-special URLs with an empty host can have their paths erased]
+    expected: FAIL
+
+  [<area>: Setting <foo:///some/path>.pathname = '' Non-special URLs with an empty host can have their paths erased]
+    expected: FAIL
+
+  [<a>: Setting <foo:/some/path>.pathname = '' Path-only URLs cannot have their paths erased]
+    expected: FAIL
+
+  [<area>: Setting <foo:/some/path>.pathname = '' Path-only URLs cannot have their paths erased]
+    expected: FAIL
+
+  [<a>: Setting <foo:/some/path>.pathname = 'test' Path-only URLs always have an initial slash]
+    expected: FAIL
+
+  [<area>: Setting <foo:/some/path>.pathname = 'test' Path-only URLs always have an initial slash]
+    expected: FAIL
+
+  [<a>: Setting <mailto:me@example.net>.pathname = '/foo' Opaque paths cannot be set]
+    expected: FAIL
+
+  [<area>: Setting <mailto:me@example.net>.pathname = '/foo' Opaque paths cannot be set]
+    expected: FAIL
+
+  [<a>: Setting <data:original>.pathname = 'new value']
+    expected: FAIL
+
+  [<area>: Setting <data:original>.pathname = 'new value']
+    expected: FAIL
+
+  [<a>: Setting <sc:original>.pathname = 'new value']
+    expected: FAIL
+
+  [<area>: Setting <sc:original>.pathname = 'new value']
+    expected: FAIL
+
+  [<a>: Setting <data:/nospace>.pathname = 'space ' Non-special URLs with non-opaque paths percent-encode U+0020]
+    expected: FAIL
+
+  [<area>: Setting <data:/nospace>.pathname = 'space ' Non-special URLs with non-opaque paths percent-encode U+0020]
+    expected: FAIL
+
+  [<a>: Setting <sc:/nospace>.pathname = 'space ']
+    expected: FAIL
+
+  [<area>: Setting <sc:/nospace>.pathname = 'space ']
+    expected: FAIL
+
+  [<a>: Setting <data:space ?query>.search = '' Drop trailing spaces from trailing opaque paths]
+    expected: FAIL
+
+  [<area>: Setting <data:space ?query>.search = '' Drop trailing spaces from trailing opaque paths]
+    expected: FAIL
+
+  [<a>: Setting <sc:space ?query>.search = '']
+    expected: FAIL
+
+  [<area>: Setting <sc:space ?query>.search = '']
+    expected: FAIL
+
+  [<a>: Setting <data:space  ?query#fragment>.search = '' Do not drop trailing spaces from non-trailing opaque paths]
+    expected: FAIL
+
+  [<area>: Setting <data:space  ?query#fragment>.search = '' Do not drop trailing spaces from non-trailing opaque paths]
+    expected: FAIL
+
+  [<a>: Setting <sc:space  ?query#fragment>.search = '']
+    expected: FAIL
+
+  [<area>: Setting <sc:space  ?query#fragment>.search = '']
+    expected: FAIL
+
+  [<a>: Setting <data:space                                                                                                                                  #fragment>.hash = '' Drop trailing spaces from trailing opaque paths]
+    expected: FAIL
+
+  [<area>: Setting <data:space                                                                                                                                  #fragment>.hash = '' Drop trailing spaces from trailing opaque paths]
+    expected: FAIL
+
+  [<a>: Setting <sc:space    #fragment>.hash = '']
+    expected: FAIL
+
+  [<area>: Setting <sc:space    #fragment>.hash = '']
+    expected: FAIL
+
+
+[url-setters-a-area.window.html?include=mailto]
+  [<a>: Setting <mailto:me@example.net>.protocol = 'http' Cannot-be-a-base URL doesn’t have a host, but URL in a special scheme must.]
+    expected: FAIL
+
+  [<area>: Setting <mailto:me@example.net>.protocol = 'http' Cannot-be-a-base URL doesn’t have a host, but URL in a special scheme must.]
+    expected: FAIL
+
+
 [url-setters-a-area.window.html?include=file]
+  [<a>: Setting <file://localhost/>.protocol = 'http' Can’t switch from file URL with no host]
+    expected: FAIL
+
+  [<area>: Setting <file://localhost/>.protocol = 'http' Can’t switch from file URL with no host]
+    expected: FAIL
+
+  [<a>: Setting <file:///test>.protocol = 'https']
+    expected: FAIL
+
+  [<area>: Setting <file:///test>.protocol = 'https']
+    expected: FAIL
+
+  [<a>: Setting <file:>.protocol = 'wss']
+    expected: FAIL
+
+  [<area>: Setting <file:>.protocol = 'wss']
+    expected: FAIL
+
   [<a>: Setting <file://hi/path>.protocol = 's']
     expected: FAIL
 
@@ -49,6 +637,42 @@
 
 
 [url-setters-a-area.window.html?exclude=(file|javascript|mailto)]
+  [<a>: Setting <http://test@example.net>.protocol = 'file' Can’t switch from URL containing username/password/port to file]
+    expected: FAIL
+
+  [<area>: Setting <http://test@example.net>.protocol = 'file' Can’t switch from URL containing username/password/port to file]
+    expected: FAIL
+
+  [<a>: Setting <https://example.net:1234>.protocol = 'file']
+    expected: FAIL
+
+  [<area>: Setting <https://example.net:1234>.protocol = 'file']
+    expected: FAIL
+
+  [<a>: Setting <wss://x:x@example.net:1234>.protocol = 'file']
+    expected: FAIL
+
+  [<area>: Setting <wss://x:x@example.net:1234>.protocol = 'file']
+    expected: FAIL
+
+  [<a>: Setting <http://example.net>.protocol = 'b' Can’t switch from special scheme to non-special]
+    expected: FAIL
+
+  [<area>: Setting <http://example.net>.protocol = 'b' Can’t switch from special scheme to non-special]
+    expected: FAIL
+
+  [<a>: Setting <https://example.net>.protocol = 's']
+    expected: FAIL
+
+  [<area>: Setting <https://example.net>.protocol = 's']
+    expected: FAIL
+
+  [<a>: Setting <ftp://example.net>.protocol = 'test']
+    expected: FAIL
+
+  [<area>: Setting <ftp://example.net>.protocol = 'test']
+    expected: FAIL
+
   [<a>: Setting <ssh://me@example.net>.protocol = 'http' Can’t switch from non-special scheme to special]
     expected: FAIL
 
@@ -73,6 +697,12 @@
   [<area>: Setting <ssh://example.net>.protocol = 'file']
     expected: FAIL
 
+  [<a>: Setting <nonsense:///test>.protocol = 'https']
+    expected: FAIL
+
+  [<area>: Setting <nonsense:///test>.protocol = 'https']
+    expected: FAIL
+
   [<a>: Setting <http://example.net>.username = '\x00\x01\t\n\r\x1f !"#$%&'()*+,-./09:;<=>?@AZ[\\\]^_`az{|}~€Éé' UTF-8 percent encoding with the userinfo encode set.]
     expected: FAIL
 
@@ -455,3 +1085,8 @@
 
 
 [url-setters-a-area.window.html?include=mailto]
+  [<a>: Setting <mailto:me@example.net>.protocol = 'http' Cannot-be-a-base URL doesn’t have a host, but URL in a special scheme must.]
+    expected: FAIL
+
+  [<area>: Setting <mailto:me@example.net>.protocol = 'http' Cannot-be-a-base URL doesn’t have a host, but URL in a special scheme must.]
+    expected: FAIL
diff --git a/testing/web-platform/meta/url/url-setters.any.js.ini b/testing/web-platform/meta/url/url-setters.any.js.ini
index 6eb88feeebe0..c02b99ea922e 100644
--- a/testing/web-platform/meta/url/url-setters.any.js.ini
+++ b/testing/web-platform/meta/url/url-setters.any.js.ini
@@ -609,6 +609,27 @@
   [URL: Setting <wpt++://domain.com:443>.port = '\t8080' Leading u0009 on non-special scheme]
     expected: FAIL
 
+  [URL: Setting <http://test@example.net>.protocol = 'file' Can’t switch from URL containing username/password/port to file]
+    expected: FAIL
+
+  [URL: Setting <https://example.net:1234>.protocol = 'file']
+    expected: FAIL
+
+  [URL: Setting <wss://x:x@example.net:1234>.protocol = 'file']
+    expected: FAIL
+
+  [URL: Setting <http://example.net>.protocol = 'b' Can’t switch from special scheme to non-special]
+    expected: FAIL
+
+  [URL: Setting <https://example.net>.protocol = 's']
+    expected: FAIL
+
+  [URL: Setting <ftp://example.net>.protocol = 'test']
+    expected: FAIL
+
+  [URL: Setting <nonsense:///test>.protocol = 'https']
+    expected: FAIL
+
 
 [url-setters.any.html?include=file]
   [URL: Setting <file://hi/path>.protocol = 's']
@@ -635,6 +656,9 @@
   [URL: Setting <file:///unicorn>.pathname = '//\\/' File URLs and (back)slashes]
     expected: FAIL
 
+  [URL: Setting <file:///test>.protocol = 'https']
+    expected: FAIL
+
 
 [url-setters.any.worker.html?include=javascript]
   [URL: Setting <javascript://x/>.username = 'wario']
@@ -834,6 +858,27 @@
   [URL: Setting <wpt++://domain.com:443>.port = '\t8080' Leading u0009 on non-special scheme]
     expected: FAIL
 
+  [URL: Setting <http://test@example.net>.protocol = 'file' Can’t switch from URL containing username/password/port to file]
+    expected: FAIL
+
+  [URL: Setting <https://example.net:1234>.protocol = 'file']
+    expected: FAIL
+
+  [URL: Setting <wss://x:x@example.net:1234>.protocol = 'file']
+    expected: FAIL
+
+  [URL: Setting <http://example.net>.protocol = 'b' Can’t switch from special scheme to non-special]
+    expected: FAIL
+
+  [URL: Setting <https://example.net>.protocol = 's']
+    expected: FAIL
+
+  [URL: Setting <ftp://example.net>.protocol = 'test']
+    expected: FAIL
+
+  [URL: Setting <nonsense:///test>.protocol = 'https']
+    expected: FAIL
+
 
 [url-setters.any.worker.html?include=file]
   [URL: Setting <file://hi/path>.protocol = 's']
@@ -860,7 +905,15 @@
   [URL: Setting <file:///unicorn>.pathname = '//\\/' File URLs and (back)slashes]
     expected: FAIL
 
+  [URL: Setting <file:///test>.protocol = 'https']
+    expected: FAIL
 
-[url-setters.any.worker.html?include=mailto]
 
 [url-setters.any.html?include=mailto]
+  [URL: Setting <mailto:me@example.net>.protocol = 'http' Cannot-be-a-base URL doesn’t have a host, but URL in a special scheme must.]
+    expected: FAIL
+
+
+[url-setters.any.worker.html?include=mailto]
+  [URL: Setting <mailto:me@example.net>.protocol = 'http' Cannot-be-a-base URL doesn’t have a host, but URL in a special scheme must.]
+    expected: FAIL