style(3p/nix): Remove 'using std::*' from types.hh r/840

It is considered bad form to use things from includes in headers, as
these directives propagate to everywhere else and can make it
confusing.

types.hh (which is includes almost literally everywhere) had some of
these directives, which this commit removes.

1 files changed, 1 insertions, 1 deletions

diff --git a/third_party/nix/src/nix-env/user-env.cc b/third_party/nix/src/nix-env/user-env.cc
index 2ca56ed966..c8eee4aac0 100644
--- a/third_party/nix/src/nix-env/user-env.cc
+++ b/third_party/nix/src/nix-env/user-env.cc
@@ -26,7 +26,7 @@ DrvInfos queryInstalled(EvalState& state, const Path& userEnv) {
 }
 
 bool createUserEnv(EvalState& state, DrvInfos& elems, const Path& profile,
-                   bool keepDerivations, const string& lockToken) {
+                   bool keepDerivations, const std::string& lockToken) {
   /* Build the components in the user environment, if they don't
      exist already. */
   PathSet drvsToBuild;