3 files changed, 22 insertions, 7 deletions
diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index a87eae325..0839b3feb 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -1930,9 +1930,11 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
   }
   // try-catch-end is written in the folded wat format as
   // (try
+  //  (do
   //   ...
+  //  )
   //  (catch
-  //    ...
+  //   ...
   //  )
   // )
   // The parenthesis wrapping 'catch' is just a syntax and does not affect
@@ -1941,7 +1943,12 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
     o << '(';
     PrintExpressionContents(currFunction, o).visit(curr);
     incIndent();
-    maybePrintImplicitBlock(curr->body, false);
+    doIndent(o, indent);
+    o << "(do";
+    incIndent();
+    maybePrintImplicitBlock(curr->body, true);
+    decIndent();
+    o << "\n";
     doIndent(o, indent);
     o << "(catch";
     incIndent();
diff --git a/src/wasm-s-parser.h b/src/wasm-s-parser.h
index 24cb7914a..6cbef5599 100644
--- a/src/wasm-s-parser.h
+++ b/src/wasm-s-parser.h
@@ -232,7 +232,7 @@ private:
   Expression* makeRefIsNull(Element& s);
   Expression* makeRefFunc(Element& s);
   Expression* makeTry(Element& s);
-  Expression* makeCatch(Element& s, Type type);
+  Expression* makeTryOrCatchBody(Element& s, Type type, bool isTry);
   Expression* makeThrow(Element& s);
   Expression* makeRethrow(Element& s);
   Expression* makeBrOnExn(Element& s);
diff --git a/src/wasm/wasm-s-parser.cpp b/src/wasm/wasm-s-parser.cpp
index a39e52b6d..eae03faa6 100644
--- a/src/wasm/wasm-s-parser.cpp
+++ b/src/wasm/wasm-s-parser.cpp
@@ -1828,12 +1828,16 @@ Expression* SExpressionWasmBuilder::makeTry(Element& s) {
   if (elementStartsWith(*s[i], "catch")) {   // empty try body
     ret->body = makeNop();
   } else {
-    ret->body = parseExpression(*s[i++]);
+    if (!elementStartsWith(*s[i], "do")) {
+      throw ParseException(
+        "try body should start with 'do'", s[i]->line, s[i]->col);
+    }
+    ret->body = makeTryOrCatchBody(*s[i++], type, true);
   }
   if (!elementStartsWith(*s[i], "catch")) {
     throw ParseException("catch clause does not exist", s[i]->line, s[i]->col);
   }
-  ret->catchBody = makeCatch(*s[i++], type);
+  ret->catchBody = makeTryOrCatchBody(*s[i++], type, false);
   ret->finalize(type);
   nameMapper.popLabelName(label);
   // create a break target if we must
@@ -1847,8 +1851,12 @@ Expression* SExpressionWasmBuilder::makeTry(Element& s) {
   return ret;
 }
 
-Expression* SExpressionWasmBuilder::makeCatch(Element& s, Type type) {
-  if (!elementStartsWith(s, "catch")) {
+Expression*
+SExpressionWasmBuilder::makeTryOrCatchBody(Element& s, Type type, bool isTry) {
+  if (isTry && !elementStartsWith(s, "do")) {
+    throw ParseException("invalid try do clause", s.line, s.col);
+  }
+  if (!isTry && !elementStartsWith(s, "catch")) {
     throw ParseException("invalid catch clause", s.line, s.col);
   }
   auto ret = allocator.alloc<Block>();