Merge remote-tracking branch 'pure11/pure11' into native

Author: andyarvanitis

pcc/runtime/purescript.cc

@@ -104,7 +104,8 @@ auto any::unthunkVariant(const any& a) -> const any& {
   return *variant;
 }
 
-auto any::operator[](const size_t rhs) const -> const any& {
+auto any::operator[](const int rhs) const -> const any& {
+  assert(rhs >= 0);
   const auto& xs = static_cast<const array&>(*this);
   return xs[rhs];
 }

pcc/runtime/purescript.hh

@@ -346,7 +346,7 @@ class any {
     return static_cast<T>(rawPointer());
   }
 
-  auto operator[](const size_t) const -> const any&;
+  auto operator[](const int) const -> const any&;
   auto at(const char *) const -> const any&;
   auto size() const -> size_t;
   auto empty() const -> bool;