Fix failurs with reuse and git ref specs

lib/spack/spack/solver/asp.py

@@ -2390,6 +2390,11 @@ def setup(
 
         self.gen.h1("Reusable concrete specs")
         self.define_concrete_input_specs(specs, self.pkgs)
+        # TODO: make a config option for this undocumented feature
+        checksummed = "SPACK_CONCRETIZER_REQUIRE_CHECKSUM" in os.environ
+        self.define_ad_hoc_versions_from_specs(
+            specs, Provenance.SPEC, allow_deprecated=allow_deprecated, require_checksum=checksummed
+        )
         if reuse:
             self.gen.fact(fn.optimize_for_reuse())
             for reusable_spec in reuse:
@@ -2421,14 +2426,9 @@ def setup(
         self.provider_requirements()
         self.external_packages()
 
-        # TODO: make a config option for this undocumented feature
-        checksummed = "SPACK_CONCRETIZER_REQUIRE_CHECKSUM" in os.environ
         self.define_package_versions_and_validate_preferences(
             self.pkgs, allow_deprecated=allow_deprecated, require_checksum=checksummed
         )
-        self.define_ad_hoc_versions_from_specs(
-            specs, Provenance.SPEC, allow_deprecated=allow_deprecated, require_checksum=checksummed
-        )
         self.define_ad_hoc_versions_from_specs(
             dev_specs,
             Provenance.DEV_SPEC,