Postgres: Accept generated columns with no mode keyword or VIRTUAL

fuzz/fuzz_seeds/postgres_2407_generated_column.sql

@@ -0,0 +1 @@
+CREATE TABLE t (a INT GENERATED ALWAYS AS (1));

src/parser/mod.rs

@@ -10376,18 +10376,15 @@ impl<'a> Parser<'a> {
                 let expr: Expr = self.with_state(ParserState::Normal, |p| p.parse_expr())?;
                 self.expect_token(&Token::RParen)?;
                 let (gen_as, expr_mode) = if self.parse_keywords(&[Keyword::STORED]) {
-                    Ok((
+                    (
                         GeneratedAs::ExpStored,
                         Some(GeneratedExpressionMode::Stored),
-                    ))
-                } else if dialect_of!(self is PostgreSqlDialect) {
-                    // Postgres' AS IDENTITY branches are above, this one needs STORED
-                    self.expected_ref("STORED", self.peek_token_ref())
+                    )
                 } else if self.parse_keywords(&[Keyword::VIRTUAL]) {
-                    Ok((GeneratedAs::Always, Some(GeneratedExpressionMode::Virtual)))
+                    (GeneratedAs::Always, Some(GeneratedExpressionMode::Virtual))
                 } else {
-                    Ok((GeneratedAs::Always, None))
-                }?;
+                    (GeneratedAs::Always, None)
+                };
 
                 Ok(Some(ColumnOption::Generated {
                     generated_as: gen_as,

tests/sqlparser_postgres.rs

@@ -11229,3 +11229,22 @@ fn parse_alter_table_attach_partition_of() {
         );
     }
 }
+
+#[test]
+fn parse_create_table_generated_column_modes() {
+    pg().verified_stmt("CREATE TABLE t (a TEXT, b TEXT GENERATED ALWAYS AS (a))");
+    pg().verified_stmt("CREATE TABLE t (a TEXT, b TEXT GENERATED ALWAYS AS (a) VIRTUAL)");
+    pg().verified_stmt("CREATE TABLE t (a TEXT, b TEXT GENERATED ALWAYS AS (a) STORED)");
+
+    pg().one_statement_parses_to(
+        r#"CREATE TABLE users (
+    first_name text NOT NULL,
+    last_name text NOT NULL,
+    name character varying(255) GENERATED ALWAYS AS (((first_name || ' '::text) || last_name)) NOT NULL
+)"#,
+        "CREATE TABLE users (\
+        first_name TEXT NOT NULL, \
+        last_name TEXT NOT NULL, \
+        name CHARACTER VARYING(255) GENERATED ALWAYS AS (((first_name || ' '::TEXT) || last_name)) NOT NULL)",
+    );
+}