[GC] Add struct.set (#3430)

Mostly straightforward after struct.get.

This renames the value field in struct.get to ref. I think this makes
more sense because struct.set has both a reference to a thing, and a
value to set onto that thing. So calling the former ref seems more
consistent, giving us ref, value. This mirrors load/store for example
where we use ptr, value, and ref is playing the role of ptr here
basically.

1 files changed, 5 insertions, 2 deletions

diff --git a/src/ir/effects.h b/src/ir/effects.h
index 80aa74cb6..d5b917d8b 100644
--- a/src/ir/effects.h
+++ b/src/ir/effects.h
@@ -563,12 +563,15 @@ private:
     }
     void visitStructGet(StructGet* curr) {
       // traps when the arg is null
-      if (curr->value->type.isNullable()) {
+      if (curr->ref->type.isNullable()) {
         parent.implicitTrap = true;
       }
     }
     void visitStructSet(StructSet* curr) {
-      WASM_UNREACHABLE("TODO (gc): struct.set");
+      // traps when the arg is null
+      if (curr->ref->type.isNullable()) {
+        parent.implicitTrap = true;
+      }
     }
     void visitArrayNew(ArrayNew* curr) {
       WASM_UNREACHABLE("TODO (gc): array.new");