1 files changed, 3 insertions, 2 deletions
diff --git a/src/wasm-s-parser.h b/src/wasm-s-parser.h
index b59af7215..dae321866 100644
--- a/src/wasm-s-parser.h
+++ b/src/wasm-s-parser.h
@@ -1031,6 +1031,7 @@ private:
   }
 
   Expression* makeMaybeBlock(Element& s, size_t i, size_t stopAt=-1) {
+    if (s.size() == i) return allocator.alloc<Nop>();
     if (s.size() == i+1) return parseExpression(s[i]);
     auto ret = allocator.alloc<Block>();
     for (; i < s.size() && i < stopAt; i++) {
@@ -1046,13 +1047,13 @@ private:
   Expression* makeLoop(Element& s) {
     auto ret = allocator.alloc<Loop>();
     size_t i = 1;
-    if (s[i]->isStr() && s[i+1]->isStr()) { // out can only be named if both are
+    if (s.size() > i + 1 && s[i]->isStr() && s[i + 1]->isStr()) { // out can only be named if both are
       ret->out = s[i]->str();
       i++;
     } else {
       ret->out = getPrefixedName("loop-out");
     }
-    if (s[i]->isStr()) {
+    if (s.size() > i && s[i]->isStr()) {
       ret->in = s[i]->str();
       i++;
     } else {