Fix some prefer-snake-case violations not getting reported (#900)

If ref part is missing loction, default to location of rule.

Fixes #899

Signed-off-by: Anders Eknert <anders@styra.com>

bundle/regal/rules/style/prefer_snake_case.rego

@@ -10,10 +10,10 @@ import data.regal.util
 
 report contains violation if {
 	some rule in input.rules
-	some ref in ast.named_refs(rule.head.ref)
-	not util.is_snake_case(ref.value)
+	some part in ast.named_refs(rule.head.ref)
+	not util.is_snake_case(part.value)
 
-	violation := result.fail(rego.metadata.chain(), result.location(ref))
+	violation := result.fail(rego.metadata.chain(), _location(rule, part))
 }
 
 report contains violation if {
@@ -22,3 +22,9 @@ report contains violation if {
 
 	violation := result.fail(rego.metadata.chain(), result.location(var))
 }
+
+_location(_, part) := result.location(part) if part.location
+
+# workaround until https://github.com/open-policy-agent/opa/issues/6860
+# is fixed and we can trust that location is included for all ref parts
+_location(rule, part) := result.location(rule.head) if not part.location

bundle/regal/rules/style/prefer_snake_case_test.rego

@@ -121,6 +121,12 @@ test_success_snake_cased_every if {
 	r == set()
 }
 
+# https://github.com/open-policy-agent/opa/issues/6860
+test_fail_location_provided_even_when_not_in_ref if {
+	r := rule.report with input as ast.with_rego_v1(`foo.Bar := true`)
+	r == expected_with_locations([{"col": 5, "file": "policy.rego", "row": 5, "text": "foo.Bar := true"}])
+}
+
 expected_with_locations(locations) := {with_location |
 	expected := {
 		"category": "style",