Harden exnref literals (#3092)

* Make `Literal::type` immutable to guarantee that we do not lose track of `Literal::exn` by changing the literal's type
* Add an assert to guarantee that we don't create `exnref` literals without an `ExceptionPackage` (for now)
* Enforce rvalue reference when creating an `exnref` Literal from a `std::unique_ptr<ExceptionPackage>`, avoiding a redundant copy by means of requiring `std::move`

1 files changed, 8 insertions, 8 deletions

diff --git a/src/wasm/literal.cpp b/src/wasm/literal.cpp
index ce1c73d56..3f635ca19 100644
--- a/src/wasm/literal.cpp
+++ b/src/wasm/literal.cpp
@@ -136,29 +136,29 @@ ExceptionPackage Literal::getExceptionPackage() const {
 
 Literal Literal::castToF32() {
   assert(type == Type::i32);
-  Literal ret(i32);
-  ret.type = Type::f32;
+  Literal ret(Type::f32);
+  ret.i32 = i32;
   return ret;
 }
 
 Literal Literal::castToF64() {
   assert(type == Type::i64);
-  Literal ret(i64);
-  ret.type = Type::f64;
+  Literal ret(Type::f64);
+  ret.i64 = i64;
   return ret;
 }
 
 Literal Literal::castToI32() {
   assert(type == Type::f32);
-  Literal ret(i32);
-  ret.type = Type::i32;
+  Literal ret(Type::i32);
+  ret.i32 = i32;
   return ret;
 }
 
 Literal Literal::castToI64() {
   assert(type == Type::f64);
-  Literal ret(i64);
-  ret.type = Type::i64;
+  Literal ret(Type::i64);
+  ret.i64 = i64;
   return ret;
 }