Get rid of most `.at` calls (#6393)

Use one of `get` or `getOr` instead which will either return a null-pointer (with a nicer error message) or a default value when the key is missing.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/resolve-system-dependencies/resolve-system-dependencies.cc b/src/resolve-system-dependencies/resolve-system-dependencies.cc
index 4dd691981..c6023eb03 100644
--- a/src/resolve-system-dependencies/resolve-system-dependencies.cc
+++ b/src/resolve-system-dependencies/resolve-system-dependencies.cc
@@ -176,7 +176,7 @@ int main(int argc, char ** argv)
             impurePaths.insert(argv[2]);
         else {
             auto drv = store->derivationFromPath(store->parseStorePath(argv[1]));
-            impurePaths = tokenizeString<StringSet>(get(drv.env, "__impureHostDeps").value_or(""));
+            impurePaths = tokenizeString<StringSet>(getOr(drv.env, "__impureHostDeps", ""));
             impurePaths.insert("/usr/lib/libSystem.dylib");
         }