[tint] Add explicit error for double leading underscores on identifiers.
The old error was super confusing.
Change-Id: Ic288570158e1162ebff90822d4e8747e86eed500
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/177661
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: James Price <jrprice@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
diff --git a/src/tint/lang/wgsl/reader/parser/lexer.cc b/src/tint/lang/wgsl/reader/parser/lexer.cc
index 117f30a..b12c0ec 100644
--- a/src/tint/lang/wgsl/reader/parser/lexer.cc
+++ b/src/tint/lang/wgsl/reader/parser/lexer.cc
@@ -1012,19 +1012,17 @@
// Consume continuing codepoint
advance(static_cast<uint32_t>(n));
-
- if (pos() - start == 2 && substr(start, 2) == "__") {
- // Identifiers prefixed with two or more underscores are not allowed.
- // We check for these in the loop to bail early and prevent quadratic parse time for
- // long sequences of ____.
- set_pos(start);
- return {};
- }
}
auto str = substr(start, pos() - start);
end_source(source);
+ if (str.length() > 1 && substr(start, 2) == "__") {
+ // Identifiers prefixed with two or more underscores are not allowed.
+ return Token{Token::Type::kError, source,
+ "identifiers must not start with two or more underscores"};
+ }
+
if (auto t = parse_keyword(str); t.has_value()) {
return Token{t.value(), source, str};
}
diff --git a/src/tint/lang/wgsl/reader/parser/lexer_test.cc b/src/tint/lang/wgsl/reader/parser/lexer_test.cc
index b2b593b..38cbd46 100644
--- a/src/tint/lang/wgsl/reader/parser/lexer_test.cc
+++ b/src/tint/lang/wgsl/reader/parser/lexer_test.cc
@@ -769,7 +769,8 @@
ASSERT_FALSE(list.empty());
auto& t = list[0];
- EXPECT_FALSE(t.IsIdentifier());
+ EXPECT_TRUE(t.IsError());
+ EXPECT_EQ(t.to_str(), "identifiers must not start with two or more underscores");
}
TEST_F(LexerTest, IdentifierTest_DoesNotStartWithNumber) {
