parser: fix IndexExpr and ArrayInit precedence error (#298)

lib/bait/lexer/lexer.bt

@@ -12,7 +12,7 @@ pub enum CommentMode {
 pub struct Lexer {
 	mut comment_mode CommentMode
 	mut text string
-	mut insert_semi bool // Insert a semicolon on \n
+	mut insert_semi bool // Insert a semicolon on next \n
 	mut val string // Value of the current token
 
 	// Position tracking
@@ -344,9 +344,11 @@ fun (mut l Lexer) skip_whitespace() {
 	for l.pos < l.text.length {
 		c := l.text[l.pos]
 		if c == `\n` {
+			// \n as semicolon is handled in simple_token()
 			if l.insert_semi {
 				return
 			}
+
 			l.pos += 1
 			l.inc_line()
 		} else if c == ` ` or c == `\t` or c == `\r` {

lib/bait/parser/expr.bt

@@ -12,14 +12,15 @@ fun (mut p Parser) expr(precedence token.Precedence) !ast.Expr {
 			node = p.dot_expr(node)!
 		} else if p.tok == .dotdot {
 			node = p.range_expr(node)!
-		} else if p.tok == .lsqr {
+		} else if p.tok == .lsqr and p.pos.line == p.prev_pos.line {
+			// If `[` is on next line, it's a different expr (see #297)
 			node = p.index_expr(node)!
 		} else if p.tok == .key_as {
 			node = p.as_cast(node)!
 		} else if p.tok.is_infix() {
 			node = p.infix_expr(node)!
 		} else {
-			panic('precedence not implemented: ${p.tok} at ${p.pos}')
+			return node
 		}
 	}
 	return node

lib/bait/parser/parser.bt

@@ -18,6 +18,7 @@ pub struct Parser {
 	mut tok token.Token
 	mut next_tok token.Token
 	mut val string
+	mut prev_pos token.Pos
 	mut pos token.Pos
 	mut pkg_name string
 	mut pkg_scope &context.Scope := 0 as any // Reference to scope of current package
@@ -267,6 +268,7 @@ fun (mut p Parser) next() {
 	}
 
 	p.val = p.lexer.val()
+	p.prev_pos = p.pos
 	p.pos = p.lexer.pos()
 }
 

tests/result/or_array_test.bt

@@ -0,0 +1,15 @@
+// SPDX-FileCopyrightText: 2023-present Lukas Neubert <[email protected]>
+// SPDX-License-Identifier: MIT
+
+fun call() ![]i32 {
+	return error("")
+}
+
+// See #297
+fun test_default_empty_array() {
+	r := call() or {
+		println(err)
+		[]i32
+	}
+	assert r.length == 0
+}