Commit e488959c1f0504dc3b2aae19d79211e725916c76 | zig

author	Isaac Freund <mail@isaacfreund.com> 2026-06-16 10:21:47+02:00
committer	Isaac Freund <mail@isaacfreund.com> 2026-07-08 11:48:59+02:00
log	e488959c1f0504dc3b2aae19d79211e725916c76
tree	eff14397567a93603eccb28d26994c4e7d295114
parent	068d4837807570550e44db99d92b25544a50cad8
signature	Commit is signed but in an unrecognized format.

grammar: remove negative lookahead causing inconsistency

It is not clear why this lookahead was added in the first place, but
it does not reflect the behavior of the Parse.zig implementation as
demonstrated with the new test case.

3 files changed, 7 insertions(+), 7 deletions(-)

doc
- langref
  - grammar.peg
lib
- std
  - zig
    parser_fuzz.zig
    parser_generated_oracle.zig

doc/langref/grammar.peg+1-1

...	...	@@ -20,7 +20,7 @@ VarDeclProto <- (KEYWORD_const / KEYWORD_var) IDENTIFIER (COLON TypeExpr)? ByteA
20	20
21	21	GlobalVarDecl <- VarDeclProto (EQUAL Expr)? SEMICOLON
22	22
23		ContainerField <- doc_comment? KEYWORD_comptime? !KEYWORD_fn (IDENTIFIER COLON)? TypeExpr ByteAlign? (EQUAL Expr)?
	23	ContainerField <- doc_comment? KEYWORD_comptime? (IDENTIFIER COLON)? TypeExpr ByteAlign? (EQUAL Expr)?
24	24
25	25	# * Block Level *
26	26	BlockStatement

lib/std/zig/parser_fuzz.zig+5

...	...	@@ -63,6 +63,11 @@ test "expression nesting" {
63	63	try checkAgainstOracle("test{*comptime 0 == 0;}");
64	64	}
65	65
	66	// Found using AFL++
	67	test "comptime fn" {
	68	try checkAgainstOracle("comptime fn()0");
	69	}
	70
66	71	fn checkAgainstOracle(source: [:0]const u8) !void {
67	72	var fba_buf: [1 << 18]u8 = undefined;
68	73	var fba: std.heap.FixedBufferAllocator = .init(&fba_buf);

lib/std/zig/parser_generated_oracle.zig+1-6

...	...	@@ -164,12 +164,7 @@ const Parser = struct {
164	164	pub fn parseContainerField(p: *Parser) bool {
165	165	return blk_0: {
166	166	const pos_0 = p.i;
167		if ((p.parsedoc_comment() or true) and (p.parseKEYWORD_comptime() or true) and blk_1: {
168		const pos_1 = p.i;
169		const match_1 = p.parseKEYWORD_fn();
170		p.i = pos_1;
171		break :blk_1 !match_1;
172		} and (blk_3: {
	167	if ((p.parsedoc_comment() or true) and (p.parseKEYWORD_comptime() or true) and (blk_3: {
173	168	const pos_3 = p.i;
174	169	if (p.parseIDENTIFIER() and p.parseCOLON()) break :blk_3 true;
175	170	p.i = pos_3;