linter: false positive with constraint-missing-not-valid (#694)

rel: #693

Author: sbdchd

crates/squawk_linter/src/rules/constraint_missing_not_valid.rs

@@ -126,6 +126,13 @@ pub(crate) fn constraint_missing_not_valid(ctx: &mut Linter, parse: &Parse<Sourc
                                 continue;
                             }
                         }
+                        if let Some(ast::Constraint::PrimaryKeyConstraint(pk)) =
+                            add_constraint.constraint()
+                        {
+                            if pk.using_index().is_some() {
+                                continue;
+                            }
+                        }
 
                         ctx.report(Violation::for_node(
                             Rule::ConstraintMissingNotValid,
@@ -206,6 +213,15 @@ ALTER TABLE distributors VALIDATE CONSTRAINT distfk;
         assert_eq!(errors.len(), 0);
     }
 
+    #[test]
+    fn adding_using_index_ok() {
+        let sql = r#"
+ALTER TABLE account ADD CONSTRAINT account_pk PRIMARY KEY USING INDEX account_pk_idx;
+        "#;
+        let errors = lint(sql, Rule::ConstraintMissingNotValid);
+        assert_eq!(errors.len(), 0);
+    }
+
     #[test]
     fn adding_check_constraint_err() {
         let sql = r#"