Error on a trailing END instead of dropping the rest of the input (#2838)

Author: LucaCappelletti94

fuzz/fuzz_seeds/postgres_trailing_end_dropped.sql

@@ -0,0 +1 @@
+SELECT 1 END

src/parser/mod.rs

@@ -554,15 +554,8 @@ impl<'a> Parser<'a> {
                 expecting_statement_delimiter = false;
             }
 
-            match &self.peek_token_ref().token {
-                Token::EOF => break,
-                // end of statement
-                Token::Word(word)
-                    if expecting_statement_delimiter && word.keyword == Keyword::END =>
-                {
-                    break;
-                }
-                _ => {}
+            if self.peek_token_ref().token == Token::EOF {
+                break;
             }
 
             if expecting_statement_delimiter {

tests/sqlparser_common.rs

@@ -23470,3 +23470,14 @@ fn parse_do_statement() {
         ParserError::ParserError("Expected: an SQL statement, found: DO".to_string())
     );
 }
+
+#[test]
+fn parse_trailing_end_keyword_is_not_silently_dropped() {
+    let dialects = all_dialects();
+    assert_eq!(
+        dialects
+            .parse_sql_statements("SELECT a FROM t1 WHERE a = b END")
+            .unwrap_err(),
+        ParserError::ParserError("Expected: end of statement, found: END".to_string())
+    );
+}

tests/sqlparser_postgres.rs

@@ -13430,3 +13430,13 @@ fn display_maintain_privilege_propagates_formatter_errors() {
         Err(fmt::Error)
     );
 }
+
+#[test]
+fn parse_case_ending_in_end_keyword_is_not_silently_dropped() {
+    // PostgreSQL reads the second `END` as a bare column alias
+    assert_eq!(
+        pg().parse_sql_statements("SELECT CASE 1 WHEN 1 THEN 1 END END FROM t")
+            .unwrap_err(),
+        ParserError::ParserError("Expected: end of statement, found: END".to_string())
+    );
+}