Remove FunctionType (#2510)

Function signatures were previously redundantly stored on Function
objects as well as on FunctionType objects. These two signature
representations had to always be kept in sync, which was error-prone
and needlessly complex. This PR takes advantage of the new ability of
Type to represent multiple value types by consolidating function
signatures as a pair of Types (params and results) stored on the
Function object.

Since there are no longer module-global named function types,
significant changes had to be made to the printing and emitting of
function types, as well as their parsing and manipulation in various
passes.

The C and JS APIs and their tests also had to be updated to remove
named function types.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/passes/RemoveImports.cpp b/src/passes/RemoveImports.cpp
index 50f7cfa3d..b3b81de3b 100644
--- a/src/passes/RemoveImports.cpp
+++ b/src/passes/RemoveImports.cpp
@@ -34,8 +34,8 @@ struct RemoveImports : public WalkerPass<PostWalker<RemoveImports>> {
     if (!func->imported()) {
       return;
     }
-    Type type = getModule()->getFunctionType(func->type)->result;
-    if (type == none) {
+    Type type = func->sig.results;
+    if (type == Type::none) {
       replaceCurrent(getModule()->allocator.alloc<Nop>());
     } else {
       Literal nopLiteral;