Use verified_stmt and drop comments in COPY INTO cast test

Author: 97nitt

tests/sqlparser_snowflake.rs

@@ -2449,16 +2449,6 @@ fn test_copy_into_with_transformations() {
 
 #[test]
 fn test_copy_into_with_cast_transformation() {
-    // Snowflake `COPY INTO` transformation lists support casts like
-    // `$1:"col"::TYPE` and `$1::TYPE`. These are distinct from the bare
-    // `$<n>[.<col>][:<elem>]` stage-load-select-item shape, so the parser
-    // must fall through to the generic select-item parser to handle the
-    // `::` cast operator.
-    //
-    // Regression: the Snowflake-specific parser used to successfully
-    // consume `$1:"col"` as a stage-load-select-item, leaving `::TYPE`
-    // behind and causing "Expected: FROM, found: ::" once the COPY INTO
-    // body tried to expect `FROM`.
     let variants = [
         concat!(
             "COPY INTO my_company.emp_basic (a) FROM ",
@@ -2476,17 +2466,13 @@ fn test_copy_into_with_cast_transformation() {
             "COPY INTO my_company.emp_basic (a, b) FROM ",
             r#"(SELECT $1:"A"::VARIANT, $1:"B"::TEXT FROM @stg)"#,
         ),
-        // Mix with an ordinary stage-load-select-item in the same list,
-        // so we don't over-correct and break the existing shape.
         concat!(
             "COPY INTO my_company.emp_basic (a, b) FROM ",
             r#"(SELECT t.$1:plain AS plain, $1:"B"::TEXT FROM @stg AS t)"#,
         ),
     ];
     for sql in variants {
-        snowflake().parse_sql_statements(sql).unwrap_or_else(|e| {
-            panic!("expected {sql:?} to parse, got {e}");
-        });
+        snowflake().verified_stmt(sql);
     }
 }