Improve statement end position handling to prevent null pointer exceptions (#162)

Author: Lance726

parser/parse_system.go

@@ -981,7 +981,7 @@ func (p *Parser) parseGrantPrivilegeStmt(pos Pos) (*GrantPrivilegeStmt, error) {
 		return nil, err
 	}
 	if len(options) != 0 {
-		statementEnd = p.last().End
+		statementEnd = p.End()
 	}
 
 	return &GrantPrivilegeStmt{

parser/parser_column.go

@@ -1082,7 +1082,7 @@ func (p *Parser) tryParseCompressionCodecs(pos Pos) (*CompressionCodec, error) {
 		}
 	}
 
-	rightParenPos := p.last().End
+	rightParenPos := p.End()
 	if err := p.expectTokenKind(TokenKindRParen); err != nil {
 		return nil, err
 	}

parser/parser_common.go

@@ -27,6 +27,13 @@ func (p *Parser) last() *Token {
 	return p.lexer.lastToken
 }
 
+func (p *Parser) End() Pos {
+	if p.last() == nil {
+		return Pos(p.lexer.current + 1)
+	}
+	return p.last().End
+}
+
 func (p *Parser) Pos() Pos {
 	last := p.last()
 	if last == nil {

parser/parser_query.go

@@ -57,7 +57,7 @@ func (p *Parser) parseTopClause(pos Pos) (*TopClause, error) {
 
 	withTies := false
 	if p.tryConsumeKeywords(KeywordWith) {
-		topEnd = p.last().End
+		topEnd = p.End()
 		if err := p.expectKeyword(KeywordTies); err != nil {
 			return nil, err
 		}
@@ -196,7 +196,7 @@ func (p *Parser) parseJoinTableExpr(_ Pos) (Expr, error) {
 
 		hasFinal := p.matchKeyword(KeywordFinal)
 		if hasFinal {
-			statementEnd = p.last().End
+			statementEnd = p.End()
 			_ = p.lexer.consumeToken()
 		}
 
@@ -587,7 +587,7 @@ func (p *Parser) parseWindowFrameClause(pos Pos) (*WindowFrameClause, error) {
 	case p.matchKeyword(KeywordCurrent):
 		currentPos := p.Pos()
 		_ = p.lexer.consumeToken()
-		rowEnd := p.last().End
+		rowEnd := p.End()
 		if err := p.expectKeyword(KeywordRow); err != nil {
 			return nil, err
 		}
@@ -622,7 +622,7 @@ func (p *Parser) parseWindowFrameClause(pos Pos) (*WindowFrameClause, error) {
 		switch {
 		case p.matchKeyword(KeywordPreceding), p.matchKeyword(KeywordFollowing):
 			direction = p.last().String
-			unboundedEnd = p.last().End
+			unboundedEnd = p.End()
 			_ = p.lexer.consumeToken()
 		default:
 			return nil, fmt.Errorf("expected PRECEDING or FOLLOWING, got %s", p.lastTokenKind())

parser/parser_table.go

@@ -344,7 +344,7 @@ func (p *Parser) parseTableSchemaClause(pos Pos) (*TableSchemaClause, error) {
 				}
 				return &TableSchemaClause{
 					SchemaPos: pos,
-					SchemaEnd: p.last().End,
+					SchemaEnd: p.End(),
 					TableFunction: &TableFunctionExpr{
 						Name: ident,
 						Args: argsExpr,
@@ -353,7 +353,7 @@ func (p *Parser) parseTableSchemaClause(pos Pos) (*TableSchemaClause, error) {
 			default:
 				return &TableSchemaClause{
 					SchemaPos: pos,
-					SchemaEnd: p.last().End,
+					SchemaEnd: p.End(),
 					AliasTable: &TableIdentifier{
 						Table: ident,
 					},
@@ -1322,7 +1322,7 @@ func (p *Parser) parseInsertStmt(pos Pos) (*InsertStmt, error) {
 	default:
 		// do nothing
 	}
-	
+
 	if err != nil {
 		return nil, err
 	}