parser: add empty statement to ast

crates/squawk_linter/src/analyze.rs

@@ -184,6 +184,7 @@ pub fn possibly_slow_stmt(stmt: &ast::Stmt) -> bool {
         | ast::Stmt::Delete(_)
         | ast::Stmt::Discard(_)
         | ast::Stmt::Do(_)
+        | ast::Stmt::EmptyStmt(_)
         | ast::Stmt::Execute(_)
         | ast::Stmt::Explain(_)
         | ast::Stmt::Fetch(_)

crates/squawk_parser/src/grammar.rs

@@ -5677,6 +5677,7 @@ struct StmtRestrictions {
 
 fn stmt(p: &mut Parser, r: &StmtRestrictions) -> Option<CompletedMarker> {
     match (p.current(), p.nth(1)) {
+        (SEMICOLON, _) => Some(empty_stmt(p)),
         (ABORT_KW, _) => Some(rollback(p)),
         (ALTER_KW, AGGREGATE_KW) => Some(alter_aggregate(p)),
         (ALTER_KW, COLLATION_KW) => Some(alter_collation(p)),
@@ -5959,6 +5960,14 @@ fn stmt(p: &mut Parser, r: &StmtRestrictions) -> Option<CompletedMarker> {
     }
 }
 
+// handle things like: ;;;select 1
+fn empty_stmt(p: &mut Parser<'_>) -> CompletedMarker {
+    assert!(p.at(SEMICOLON));
+    let m = p.start();
+    p.bump(SEMICOLON);
+    m.complete(p, EMPTY_STMT)
+}
+
 // ALTER STATISTICS name OWNER TO { new_owner | CURRENT_ROLE | CURRENT_USER | SESSION_USER }
 // ALTER STATISTICS name RENAME TO new_name
 // ALTER STATISTICS name SET SCHEMA new_schema
@@ -15293,17 +15302,16 @@ fn set_data_type(p: &mut Parser<'_>) {
 pub(crate) fn entry_point(p: &mut Parser) {
     let m = p.start();
     while !p.at(EOF) {
-        // handle things like: ;;;select 1
-        if p.eat(SEMICOLON) {
-            continue;
-        }
         let parsed_stmt = stmt(
             p,
             &StmtRestrictions {
                 begin_end_allowed: true,
             },
         );
-        if !p.at(EOF) && parsed_stmt.is_some() {
+        if !p.at(EOF)
+            && let Some(marker) = parsed_stmt
+            && marker.kind() != EMPTY_STMT
+        {
             p.expect(SEMICOLON);
         }
     }

crates/squawk_parser/tests/snapshots/tests__alter_table_err.snap

@@ -16,7 +16,8 @@ SOURCE_FILE
   WHITESPACE " "
   ERROR
     BOOLEAN_KW "boolean"
-  SEMICOLON ";"
+  EMPTY_STMT
+    SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- mismatch options"
   WHITESPACE "\n"

crates/squawk_parser/tests/snapshots/tests__drop_rule_ok.snap

@@ -21,7 +21,8 @@ SOURCE_FILE
           NAME_REF
             IDENT "t"
   SEMICOLON ";"
-  SEMICOLON ";"
+  EMPTY_STMT
+    SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- full"
   WHITESPACE "\n"

crates/squawk_syntax/src/postgresql.ungram

@@ -861,6 +861,9 @@ Truncate =
   ('restart' 'identity' | 'continue' 'identity')?
   ('cascade' | 'restrict')?
 
+EmptyStmt =
+  ';'
+
 LikeOption =
   ('including' | 'excluding')
   ('comments'
@@ -3618,7 +3621,7 @@ Stmt =
 | Vacuum
 | Values
 | ParenSelect
-| ';'
+| EmptyStmt
 
 
 SourceFile =