Fix out-of-bounds type stack read after rethrow in c-writer

src/c-writer.cc

@@ -4187,7 +4187,9 @@ void CWriter::Write(const ExprList& exprs) {
         Write("wasm_rt_load_exception(", ex, "_tag, ", ex, "_size, ", ex, ");",
               Newline());
         WriteThrow();
-      } break;
+        // Stop processing this ExprList, since the following are unreachable.
+        return;
+      }
 
       case ExprType::Try: {
         const TryExpr& tryexpr = *cast<TryExpr>(&expr);

test/wasm2c/unreachable-after-rethrow.txt

@@ -0,0 +1,15 @@
+;;; TOOL: run-spec-wasm2c
+;;; ARGS*: --enable-exceptions
+(module
+  (memory 1)
+  (func (export "test")
+    try
+      nop
+    catch_all
+      rethrow 0
+      i32.store
+    end))
+(assert_return (invoke "test"))
+(;; STDOUT ;;;
+1/1 tests passed.
+;;; STDOUT ;;)