lib/types: make pattern of strMatching accessible

lib/tests/modules.sh

@@ -190,6 +190,9 @@ checkConfigOutput '^420$' config.bare-submodule.deep ./declare-bare-submodule.ni
 checkConfigOutput '^2$' config.bare-submodule.deep ./declare-bare-submodule.nix ./declare-bare-submodule-deep-option.nix ./define-shorthandOnlyDefinesConfig-true.nix
 checkConfigError 'The option .bare-submodule.deep. in .*/declare-bare-submodule-deep-option.nix. is already declared in .*/declare-bare-submodule-deep-option-duplicate.nix' config.bare-submodule.deep ./declare-bare-submodule.nix ./declare-bare-submodule-deep-option.nix  ./declare-bare-submodule-deep-option-duplicate.nix
 
+# Check that strMatching can be merged
+checkConfigOutput '^"strMatching.*"$' options.sm.type.name ./strMatching-merge.nix
+
 # Check integer types.
 # unsigned
 checkConfigOutput '^42$' config.value ./declare-int-unsigned-value.nix ./define-value-int-positive.nix

lib/tests/modules/strMatching-merge.nix

@@ -0,0 +1,15 @@
+{ lib, ... }:
+{
+  imports = [
+    {
+      options.sm = lib.mkOption {
+        type = lib.types.strMatching "\(.*\)";
+      };
+    }
+    {
+      options.sm = lib.mkOption {
+        type = lib.types.strMatching "\(.*\)";
+      };
+    }
+  ];
+}

lib/types.nix

@@ -443,6 +443,11 @@ rec {
       descriptionClass = "noun";
       check = x: str.check x && builtins.match pattern x != null;
       inherit (str) merge;
+      functor = defaultFunctor "strMatching" // {
+        type = payload: strMatching payload.pattern;
+        payload = { inherit pattern; };
+        binOp = lhs: rhs: if lhs == rhs then lhs else null;
+      };
     };
 
     # Merge multiple definitions by concatenating them (with the given