New approach to handle at parenthesis boundary

Author: isaacparker0

src/parser/mod.rs

@@ -1818,7 +1818,14 @@ impl<'a> Parser<'a> {
                     } else if let Some(lambda) = self.try_parse_lambda()? {
                         return Ok(lambda);
                     } else {
-                        let exprs = self.parse_comma_separated(Parser::parse_expr)?;
+                        // Parentheses create a "normal" expression context.
+                        // This ensures that e.g. `NOT NULL` inside parens is parsed
+                        // as `IS NOT NULL` (for dialects that support it), while
+                        // `NOT NULL` outside parens in a column definition context
+                        // remains a column constraint.
+                        let exprs = self.with_state(ParserState::Normal, |p| {
+                            p.parse_comma_separated(Parser::parse_expr)
+                        })?;
                         match exprs.len() {
                             0 => return Err(ParserError::ParserError(
                                 "Internal parser error: parse_comma_separated returned empty list"
@@ -8787,18 +8794,18 @@ impl<'a> Parser<'a> {
             Ok(Some(ColumnOption::Null))
         } else if self.parse_keyword(Keyword::DEFAULT) {
             Ok(Some(ColumnOption::Default(
-                self.parse_column_option_expr()?,
+                self.parse_expr()?,
             )))
         } else if dialect_of!(self is ClickHouseDialect| GenericDialect)
             && self.parse_keyword(Keyword::MATERIALIZED)
         {
             Ok(Some(ColumnOption::Materialized(
-                self.parse_column_option_expr()?,
+                self.parse_expr()?,
             )))
         } else if dialect_of!(self is ClickHouseDialect| GenericDialect)
             && self.parse_keyword(Keyword::ALIAS)
         {
-            Ok(Some(ColumnOption::Alias(self.parse_column_option_expr()?)))
+            Ok(Some(ColumnOption::Alias(self.parse_expr()?)))
         } else if dialect_of!(self is ClickHouseDialect| GenericDialect)
             && self.parse_keyword(Keyword::EPHEMERAL)
         {
@@ -8808,7 +8815,7 @@ impl<'a> Parser<'a> {
                 Ok(Some(ColumnOption::Ephemeral(None)))
             } else {
                 Ok(Some(ColumnOption::Ephemeral(Some(
-                    self.parse_column_option_expr()?,
+                    self.parse_expr()?,
                 ))))
             }
         } else if self.parse_keywords(&[Keyword::PRIMARY, Keyword::KEY]) {
@@ -8922,7 +8929,7 @@ impl<'a> Parser<'a> {
         } else if self.parse_keywords(&[Keyword::ON, Keyword::UPDATE])
             && dialect_of!(self is MySqlDialect | GenericDialect)
         {
-            let expr = self.parse_column_option_expr()?;
+            let expr = self.parse_expr()?;
             Ok(Some(ColumnOption::OnUpdate(expr)))
         } else if self.parse_keyword(Keyword::GENERATED) {
             self.parse_optional_column_option_generated()
@@ -8941,7 +8948,7 @@ impl<'a> Parser<'a> {
             && dialect_of!(self is MySqlDialect | GenericDialect)
         {
             Ok(Some(ColumnOption::Srid(Box::new(
-                self.parse_column_option_expr()?,
+                self.parse_expr()?,
             ))))
         } else if self.parse_keyword(Keyword::IDENTITY)
             && dialect_of!(self is MsSqlDialect | GenericDialect)
@@ -8984,39 +8991,6 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// When parsing some column option expressions we need to revert to [ParserState::Normal] since
-    /// `NOT NULL` is allowed as an alias for `IS NOT NULL`.
-    /// In those cases we use this helper instead of calling [Parser::parse_expr] directly.
-    ///
-    /// For example, consider these `CREATE TABLE` statements:
-    /// ```sql
-    /// CREATE TABLE foo (abc BOOL DEFAULT (42 NOT NULL) NOT NULL);
-    /// ```
-    /// vs
-    /// ```sql
-    /// CREATE TABLE foo (abc BOOL NOT NULL);
-    /// ```
-    ///
-    /// In the first we should parse the inner portion of `(42 NOT NULL)` as [Expr::IsNotNull],
-    /// whereas is both statements that trailing `NOT NULL` should only be parsed as a
-    /// [ColumnOption::NotNull].
-    fn parse_column_option_expr(&mut self) -> Result<Expr, ParserError> {
-        if self.peek_token_ref().token == Token::LParen {
-            let mut expr = self.with_state(ParserState::Normal, |p| p.parse_prefix())?;
-            expr = self.parse_compound_expr(expr, vec![])?;
-            loop {
-                let next_precedence = self.get_next_precedence()?;
-                if next_precedence == 0 || self.peek_token_ref().token == Token::Period {
-                    break;
-                }
-                expr = self.parse_infix(expr, next_precedence)?;
-            }
-            Ok(expr)
-        } else {
-            Ok(self.parse_expr()?)
-        }
-    }
-
     pub(crate) fn parse_tag(&mut self) -> Result<Tag, ParserError> {
         let name = self.parse_object_name(false)?;
         self.expect_token(&Token::Eq)?;