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-instantiate/nix-instantiate.cc b/third_party/nix/src/nix-instantiate/nix-instantiate.cc
index 95e5341ade..8e1c7afe1c 100644
--- a/third_party/nix/src/nix-instantiate/nix-instantiate.cc
+++ b/third_party/nix/src/nix-instantiate/nix-instantiate.cc
@@ -62,7 +62,7 @@ void processExpr(EvalState& state, const Strings& attrPaths, bool parseOnly,
         Path drvPath = i.queryDrvPath();
 
         /* What output do we want? */
-        string outputName = i.queryOutputName();
+        std::string outputName = i.queryOutputName();
         if (outputName.empty()) {
           throw Error(
               format("derivation '%1%' lacks an 'outputName' attribute ") %