Preserve Function HeapTypes (#3952)

When using nominal types, func.ref of two functions with identical signatures
but different HeapTypes will yield different types. To preserve these semantics,
Functions need to track their HeapTypes, not just their Signatures.

This PR replaces the Signature field in Function with a HeapType field and adds
new utility methods to make it almost as simple to update and query the function
HeapType as it was to update and query the Function Signature.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/ir/ExpressionAnalyzer.cpp b/src/ir/ExpressionAnalyzer.cpp
index 0c6081b03..260a9a6c4 100644
--- a/src/ir/ExpressionAnalyzer.cpp
+++ b/src/ir/ExpressionAnalyzer.cpp
@@ -60,7 +60,7 @@ bool ExpressionAnalyzer::isResultUsed(ExpressionStack& stack, Function* func) {
     }
   }
   // The value might be used, so it depends on if the function returns
-  return func->sig.results != Type::none;
+  return func->getResults() != Type::none;
 }
 
 // Checks if a value is dropped.