[parser] Attempt to crash instead of inserting after eof
In reference to https://github.com/dart-lang/sdk/issues/46505 I'd say
it's strictly better to crash than to (get the Analyzer to) go into
an infinite loop.
Change-Id: I6706353061272c8df19f156da6fb6659e3b0e30a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/205785
Commit-Queue: Jens Johansen <jensj@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
diff --git a/pkg/_fe_analyzer_shared/lib/src/parser/token_stream_rewriter.dart b/pkg/_fe_analyzer_shared/lib/src/parser/token_stream_rewriter.dart
index b577fba..e033fca 100644
--- a/pkg/_fe_analyzer_shared/lib/src/parser/token_stream_rewriter.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/parser/token_stream_rewriter.dart
@@ -22,11 +22,15 @@
/// open parenthesis. If [insertIdentifier] is true, then a synthetic
/// identifier is included between the open and close parenthesis.
Token insertParens(Token token, bool includeIdentifier) {
- // Assert that the token is not eof, though allow an eof-token if the offset
+ // Throw if the token is eof, though allow an eof-token if the offset
// is negative. The last part is because [syntheticPreviousToken] sometimes
// creates eof tokens that aren't the real eof-token that has a negative
// offset (which wouldn't be valid for the real eof).
- assert(!token.isEof || token.offset < 0);
+ if (!(!token.isEof || token.offset < 0)) {
+ // Inserting here could cause a infinite loop. We prefer to crash.
+ throw 'Internal Error: Rewriting at eof.';
+ }
+
Token next = token.next!;
int offset = next.charOffset;
BeginToken leftParen =
@@ -49,11 +53,15 @@
/// Insert [newToken] after [token] and return [newToken].
Token insertToken(Token token, Token newToken) {
- // Assert that the token is not eof, though allow an eof-token if the offset
+ // Throw if the token is eof, though allow an eof-token if the offset
// is negative. The last part is because [syntheticPreviousToken] sometimes
// creates eof tokens that aren't the real eof-token that has a negative
// offset (which wouldn't be valid for the real eof).
- assert(!token.isEof || token.offset < 0);
+ if (!(!token.isEof || token.offset < 0)) {
+ // Inserting here could cause a infinite loop. We prefer to crash.
+ throw 'Internal Error: Rewriting at eof.';
+ }
+
_setNext(newToken, token.next!);
// A no-op rewriter could skip this step.
@@ -65,11 +73,15 @@
/// Move [endGroup] (a synthetic `)`, `]`, or `}` token) and associated
/// error token after [token] in the token stream and return [endGroup].
Token moveSynthetic(Token token, Token endGroup) {
- // Assert that the token is not eof, though allow an eof-token if the offset
+ // Throw if the token is eof, though allow an eof-token if the offset
// is negative. The last part is because [syntheticPreviousToken] sometimes
// creates eof tokens that aren't the real eof-token that has a negative
// offset (which wouldn't be valid for the real eof).
- assert(!token.isEof || token.offset < 0);
+ if (!(!token.isEof || token.offset < 0)) {
+ // Inserting here could cause a infinite loop. We prefer to crash.
+ throw 'Internal Error: Rewriting at eof.';
+ }
+
// ignore:unnecessary_null_comparison
assert(endGroup.beforeSynthetic != null);
if (token == endGroup) return endGroup;
