libsass-2908.patch

diff --git a/src/extender.cpp b/src/extender.cpp
index 6d96b8d0..8456a6a1 100644
--- a/src/extender.cpp
+++ b/src/extender.cpp
@@ -287,11 +287,11 @@ namespace Sass {
   // Note: this function could need some logic cleanup
   // ##########################################################################
   void Extender::addExtension(
-    SelectorListObj& extender,
-    SimpleSelectorObj& target,
+    SelectorListObj extender,
+    SimpleSelectorObj target,
     // get get passed a pointer
     ExtendRuleObj extend,
-    CssMediaRuleObj& mediaQueryContext)
+    CssMediaRuleObj mediaQueryContext)
   {
 
     auto rules = selectors.find(target);
@@ -419,7 +419,7 @@ namespace Sass {
 
     ExtSelExtMap additionalExtensions;
 
-    for (Extension extension : oldExtensions) {
+    for (const Extension &extension : oldExtensions) {
       ExtSelExtMapEntry& sources = extensions[extension.target];
       std::vector<ComplexSelectorObj> selectors(extendComplex(
         extension.extender,
diff --git a/src/extender.hpp b/src/extender.hpp
index 6b2938e5..a5879e2e 100644
--- a/src/extender.hpp
+++ b/src/extender.hpp
@@ -206,11 +206,11 @@ namespace Sass {
     // within the same context. A `null` context indicates no media queries.
     // ##########################################################################
     void addExtension(
-      SelectorListObj& extender,
-      SimpleSelectorObj& target,
+      SelectorListObj extender,
+      SimpleSelectorObj target,
       // gets passed by pointer
       ExtendRuleObj extend,
-      CssMediaRuleObj& mediaQueryContext);
+      CssMediaRuleObj mediaQueryContext);
 
     // ##########################################################################
     // The set of all simple selectors in style rules handled
diff --git a/src/extension.cpp b/src/extension.cpp
index 0b10904d..05614db2 100644
--- a/src/extension.cpp
+++ b/src/extension.cpp
@@ -11,7 +11,7 @@ namespace Sass {
   // ##########################################################################
   // Static function to create a copy with a new extender
   // ##########################################################################
-  Extension Extension::withExtender(ComplexSelectorObj newExtender)
+  Extension Extension::withExtender(ComplexSelectorObj newExtender) const
   {
     Extension extension(newExtender);
     extension.specificity = specificity;
diff --git a/src/extension.hpp b/src/extension.hpp
index d6e1d1d7..3580cf69 100644
--- a/src/extension.hpp
+++ b/src/extension.hpp
@@ -80,7 +80,7 @@ namespace Sass {
     // compatible with the query context for this extender.
     void assertCompatibleMediaContext(CssMediaRuleObj mediaContext, Backtraces& traces) const;
 
-    Extension withExtender(ComplexSelectorObj newExtender);
+    Extension withExtender(ComplexSelectorObj newExtender) const;
 
   };