diff --git a/js/src/frontend/Parser.cpp b/js/src/frontend/Parser.cpp
index d53265706bd..538ebb30493 100644
--- a/js/src/frontend/Parser.cpp
+++ b/js/src/frontend/Parser.cpp
@@ -2125,7 +2125,8 @@ Parser<FullParseHandler>::functionArgsAndBody(ParseNode *pn, HandleFunction fun,
             // Move the syntax parser to the current position in the stream.
             TokenStream::Position position(keepAtoms);
             tokenStream.tell(&position);
-            parser->tokenStream.seek(position, tokenStream);
+            if (!parser->tokenStream.seek(position, tokenStream))
+                return false;
 
             ParseContext<SyntaxParseHandler> funpc(parser, outerpc, SyntaxParseHandler::null(), funbox,
                                                    newDirectives, outerpc->staticLevel + 1,
@@ -2149,7 +2150,8 @@ Parser<FullParseHandler>::functionArgsAndBody(ParseNode *pn, HandleFunction fun,
 
             // Advance this parser over tokens processed by the syntax parser.
             parser->tokenStream.tell(&position);
-            tokenStream.seek(position, parser->tokenStream);
+            if (!tokenStream.seek(position, parser->tokenStream))
+                return false;
 
             // Update the end position of the parse node.
             pn->pn_pos.end = tokenStream.currentToken().pos.end;
diff --git a/js/src/frontend/TokenStream.cpp b/js/src/frontend/TokenStream.cpp
index c59912d2f7b..106fb86782d 100644
--- a/js/src/frontend/TokenStream.cpp
+++ b/js/src/frontend/TokenStream.cpp
@@ -160,20 +160,23 @@ TokenStream::SourceCoords::add(uint32_t lineNum, uint32_t lineStartOffset)
     }
 }
 
-MOZ_ALWAYS_INLINE void
+MOZ_ALWAYS_INLINE bool
 TokenStream::SourceCoords::fill(const TokenStream::SourceCoords &other)
 {
     JS_ASSERT(lineStartOffsets_.back() == MAX_PTR);
     JS_ASSERT(other.lineStartOffsets_.back() == MAX_PTR);
 
     if (lineStartOffsets_.length() >= other.lineStartOffsets_.length())
-        return;
+        return true;
 
     uint32_t sentinelIndex = lineStartOffsets_.length() - 1;
     lineStartOffsets_[sentinelIndex] = other.lineStartOffsets_[sentinelIndex];
 
-    for (size_t i = sentinelIndex + 1; i < other.lineStartOffsets_.length(); i++)
-        (void)lineStartOffsets_.append(other.lineStartOffsets_[i]);
+    for (size_t i = sentinelIndex + 1; i < other.lineStartOffsets_.length(); i++) {
+        if (!lineStartOffsets_.append(other.lineStartOffsets_[i]))
+            return false;
+    }
+    return true;
 }
 
 MOZ_ALWAYS_INLINE uint32_t
@@ -537,11 +540,13 @@ TokenStream::seek(const Position &pos)
         tokens[(cursor + 1 + i) & ntokensMask] = pos.lookaheadTokens[i];
 }
 
-void
+bool
 TokenStream::seek(const Position &pos, const TokenStream &other)
 {
-    srcCoords.fill(other.srcCoords);
+    if (!srcCoords.fill(other.srcCoords))
+        return false;
     seek(pos);
+    return true;
 }
 
 bool
diff --git a/js/src/frontend/TokenStream.h b/js/src/frontend/TokenStream.h
index 85b00192282..d24f821563a 100644
--- a/js/src/frontend/TokenStream.h
+++ b/js/src/frontend/TokenStream.h
@@ -614,7 +614,7 @@ class MOZ_STACK_CLASS TokenStream
     void advance(size_t position);
     void tell(Position *);
     void seek(const Position &pos);
-    void seek(const Position &pos, const TokenStream &other);
+    bool seek(const Position &pos, const TokenStream &other);
 
     size_t positionToOffset(const Position &pos) const {
         return pos.buf - userbuf.base();
@@ -710,7 +710,7 @@ class MOZ_STACK_CLASS TokenStream
         SourceCoords(ExclusiveContext *cx, uint32_t ln);
 
         void add(uint32_t lineNum, uint32_t lineStartOffset);
-        void fill(const SourceCoords &other);
+        bool fill(const SourceCoords &other);
 
         bool isOnThisLine(uint32_t offset, uint32_t lineNum) const {
             uint32_t lineIndex = lineNumToIndex(lineNum);