fix

tests/binaryen/block-pre.js

@@ -0,0 +1,26 @@
+var binaryen = require("binaryen");
+var mod = binaryen.parseText(`
+(module
+  (global $ref (mut i32) (i32.const 1))
+  (func $test
+    (call $release
+      (block (result i32)
+        (global.get $ref)
+        (global.set $ref
+          (call $retain
+            (i32.const 2) (; some-expression-that-might-conflict-with-a-temp ;)
+          )
+        )
+      )
+    )
+  )
+  (func $retain (param i32) (result i32)
+    (local.get 0)
+  )
+  (func $release (param i32)
+    (nop)
+  )
+)
+`);
+if (!mod.validate()) console.log(":-(");
+else console.log(mod.emitText());