diff --git a/dom/src/base/nsLocation.cpp b/dom/src/base/nsLocation.cpp
index a3e7422a03d..ad9d8c20f76 100644
--- a/dom/src/base/nsLocation.cpp
+++ b/dom/src/base/nsLocation.cpp
@@ -57,7 +57,6 @@
 #include "nsCOMPtr.h"
 #include "nsEscape.h"
 #include "nsJSUtils.h"
-#include "nsIScriptSecurityManager.h"
 #include "nsIDOMWindow.h"
 #include "nsIDOMDocument.h"
 #include "nsIDocument.h"
@@ -428,18 +427,17 @@ NS_IMETHODIMP
 nsLocation::SetHash(const nsAString& aHash)
 {
   nsCOMPtr<nsIURI> uri;
-  nsresult result = NS_OK;
-
-  result = GetWritableURI(getter_AddRefs(uri));
+  nsresult rv = GetWritableURI(getter_AddRefs(uri));
 
   nsCOMPtr<nsIURL> url(do_QueryInterface(uri));
-
   if (url) {
-    url->SetRef(NS_ConvertUTF16toUTF8(aHash));
-    SetURI(url);
+    rv = url->SetRef(NS_ConvertUTF16toUTF8(aHash));
+    if (NS_SUCCEEDED(rv)) {
+      SetURI(url);
+    }
   }
 
-  return result;
+  return rv;
 }
 
 NS_IMETHODIMP
@@ -469,16 +467,16 @@ NS_IMETHODIMP
 nsLocation::SetHost(const nsAString& aHost)
 {
   nsCOMPtr<nsIURI> uri;
-  nsresult result;
-
-  result = GetWritableURI(getter_AddRefs(uri));
+  nsresult rv = GetWritableURI(getter_AddRefs(uri));
 
   if (uri) {
-    uri->SetHostPort(NS_ConvertUTF16toUTF8(aHost));
-    SetURI(uri);
+    rv = uri->SetHostPort(NS_ConvertUTF16toUTF8(aHost));
+    if (NS_SUCCEEDED(rv)) {
+      SetURI(uri);
+    }
   }
 
-  return result;
+  return rv;
 }
 
 NS_IMETHODIMP
@@ -508,16 +506,16 @@ NS_IMETHODIMP
 nsLocation::SetHostname(const nsAString& aHostname)
 {
   nsCOMPtr<nsIURI> uri;
-  nsresult result;
-
-  result = GetWritableURI(getter_AddRefs(uri));
+  nsresult rv = GetWritableURI(getter_AddRefs(uri));
 
   if (uri) {
-    uri->SetHost(NS_ConvertUTF16toUTF8(aHostname));
-    SetURI(uri);
+    rv = uri->SetHost(NS_ConvertUTF16toUTF8(aHostname));
+    if (NS_SUCCEEDED(rv)) {
+      SetURI(uri);
+    }
   }
 
-  return result;
+  return rv;
 }
 
 NS_IMETHODIMP
@@ -687,16 +685,16 @@ NS_IMETHODIMP
 nsLocation::SetPathname(const nsAString& aPathname)
 {
   nsCOMPtr<nsIURI> uri;
-  nsresult result = NS_OK;
-
-  result = GetWritableURI(getter_AddRefs(uri));
+  nsresult rv = GetWritableURI(getter_AddRefs(uri));
 
   if (uri) {
-    uri->SetPath(NS_ConvertUTF16toUTF8(aPathname));
-    SetURI(uri);
+    rv = uri->SetPath(NS_ConvertUTF16toUTF8(aPathname));
+    if (NS_SUCCEEDED(rv)) {
+      SetURI(uri);
+    }
   }
 
-  return result;
+  return rv;
 }
 
 NS_IMETHODIMP
@@ -730,9 +728,7 @@ NS_IMETHODIMP
 nsLocation::SetPort(const nsAString& aPort)
 {
   nsCOMPtr<nsIURI> uri;
-  nsresult result = NS_OK;
-
-  result = GetWritableURI(getter_AddRefs(uri));
+  nsresult rv = GetWritableURI(getter_AddRefs(uri));
 
   if (uri) {
     // perhaps use nsReadingIterators at some point?
@@ -749,11 +745,13 @@ nsLocation::SetPort(const nsAString& aPort)
       }
     }
 
-    uri->SetPort(port);
-    SetURI(uri);
+    rv = uri->SetPort(port);
+    if (NS_SUCCEEDED(rv)) {
+      SetURI(uri);
+    }
   }
 
-  return result;
+  return rv;
 }
 
 NS_IMETHODIMP
@@ -784,16 +782,16 @@ NS_IMETHODIMP
 nsLocation::SetProtocol(const nsAString& aProtocol)
 {
   nsCOMPtr<nsIURI> uri;
-  nsresult result = NS_OK;
-
-  result = GetWritableURI(getter_AddRefs(uri));
+  nsresult rv = GetWritableURI(getter_AddRefs(uri));
 
   if (uri) {
-    uri->SetScheme(NS_ConvertUTF16toUTF8(aProtocol));
-    SetURI(uri);
+    rv = uri->SetScheme(NS_ConvertUTF16toUTF8(aProtocol));
+    if (NS_SUCCEEDED(rv)) {
+      SetURI(uri);
+    }
   }
 
-  return result;
+  return rv;
 }
 
 NS_IMETHODIMP
@@ -826,17 +824,17 @@ NS_IMETHODIMP
 nsLocation::SetSearch(const nsAString& aSearch)
 {
   nsCOMPtr<nsIURI> uri;
-  nsresult result = NS_OK;
-
-  result = GetWritableURI(getter_AddRefs(uri));
+  nsresult rv = GetWritableURI(getter_AddRefs(uri));
 
   nsCOMPtr<nsIURL> url(do_QueryInterface(uri));
   if (url) {
-    result = url->SetQuery(NS_ConvertUTF16toUTF8(aSearch));
-    SetURI(uri);
+    rv = url->SetQuery(NS_ConvertUTF16toUTF8(aSearch));
+    if (NS_SUCCEEDED(rv)) {
+      SetURI(uri);
+    }
   }
 
-  return result;
+  return rv;
 }
 
 NS_IMETHODIMP
diff --git a/netwerk/base/src/nsStandardURL.cpp b/netwerk/base/src/nsStandardURL.cpp
index 6a8974336a1..385c0e1bdfb 100644
--- a/netwerk/base/src/nsStandardURL.cpp
+++ b/netwerk/base/src/nsStandardURL.cpp
@@ -1425,7 +1425,7 @@ nsStandardURL::SetHost(const nsACString &input)
     if (mURLType == URLTYPE_NO_AUTHORITY) {
         if (flat.IsEmpty())
             return NS_OK;
-        NS_ERROR("cannot set host on no-auth url");
+        NS_WARNING("cannot set host on no-auth url");
         return NS_ERROR_UNEXPECTED;
     }
 
@@ -1499,7 +1499,7 @@ nsStandardURL::SetPort(PRInt32 port)
         return NS_OK;
 
     if (mURLType == URLTYPE_NO_AUTHORITY) {
-        NS_ERROR("cannot set port on no-auth url");
+        NS_WARNING("cannot set port on no-auth url");
         return NS_ERROR_UNEXPECTED;
     }