Rename AsReturnSubquery to AsReturnExpr & remove non-subquery error

Author: aharpervc

src/ast/ddl.rs

@@ -2346,7 +2346,7 @@ impl fmt::Display for CreateFunction {
         if let Some(CreateFunctionBody::Return(function_body)) = &self.function_body {
             write!(f, " RETURN {function_body}")?;
         }
-        if let Some(CreateFunctionBody::AsReturnSubquery(function_body)) = &self.function_body {
+        if let Some(CreateFunctionBody::AsReturnExpr(function_body)) = &self.function_body {
             write!(f, " AS RETURN {function_body}")?;
         }
         if let Some(CreateFunctionBody::AsReturnSelect(function_body)) = &self.function_body {

src/ast/mod.rs

@@ -8789,7 +8789,7 @@ pub enum CreateFunctionBody {
     /// ```
     ///
     /// [MsSql]: https://learn.microsoft.com/en-us/sql/t-sql/statements/create-function-transact-sql
-    AsReturnSubquery(Expr),
+    AsReturnExpr(Expr),
 
     /// Function body expression using the 'AS RETURN' keywords, with an un-parenthesized SELECT query
     ///

src/parser/mod.rs

@@ -5264,14 +5264,7 @@ impl<'a> Parser<'a> {
             }))
         } else if self.parse_keyword(Keyword::RETURN) {
             if self.peek_token() == Token::LParen {
-                let expr = self.parse_expr()?;
-                if !matches!(expr, Expr::Subquery(_)) {
-                    parser_err!(
-                        "Expected a subquery after RETURN",
-                        self.peek_token().span.start
-                    )?
-                }
-                Some(CreateFunctionBody::AsReturnSubquery(expr))
+                Some(CreateFunctionBody::AsReturnExpr(self.parse_expr()?))
             } else if self.peek_keyword(Keyword::SELECT) {
                 let select = self.parse_select()?;
                 Some(CreateFunctionBody::AsReturnSelect(select))