Offer suggestions for nix-env -i

Closes https://github.com/NixOS/nix/issues/972

2 files changed, 2 insertions, 2 deletions

diff --git a/src/libstore/names.cc b/src/libstore/names.cc
index ce808accc..54c95055d 100644
--- a/src/libstore/names.cc
+++ b/src/libstore/names.cc
@@ -42,7 +42,7 @@ DrvName::~DrvName()
 { }
 
 
-bool DrvName::matches(DrvName & n)
+bool DrvName::matches(const DrvName & n)
 {
     if (name != "*") {
         if (!regex) {
diff --git a/src/libstore/names.hh b/src/libstore/names.hh
index bc62aac93..3f861bc44 100644
--- a/src/libstore/names.hh
+++ b/src/libstore/names.hh
@@ -19,7 +19,7 @@ struct DrvName
     DrvName(std::string_view s);
     ~DrvName();
 
-    bool matches(DrvName & n);
+    bool matches(const DrvName & n);
 
 private:
     std::unique_ptr<Regex> regex;