diff --git a/lib/c-api/examples/imports-exports.c b/lib/c-api/examples/imports-exports.c
index aaf4186c3..e56a72327 100644
--- a/lib/c-api/examples/imports-exports.c
+++ b/lib/c-api/examples/imports-exports.c
@@ -63,7 +63,8 @@ int main(int argc, const char* argv[]) {
 
     printf("Instantiating module...\n");
     wasm_instance_t* instance = wasm_instance_new(store, module, &import_object, NULL);
-    wasm_extern_vec_delete(&import_object);
+    wasm_func_delete(host_func);
+    wasm_global_delete(host_global);
 
     if (!instance) {
       printf("> Error instantiating module!\n");
diff --git a/lib/c-api/src/wasm_c_api/macros.rs b/lib/c-api/src/wasm_c_api/macros.rs
index 22a251bb2..04aa90f3d 100644
--- a/lib/c-api/src/wasm_c_api/macros.rs
+++ b/lib/c-api/src/wasm_c_api/macros.rs
@@ -3,6 +3,7 @@ macro_rules! wasm_declare_vec_inner {
         name: $name:ident,
         ty: $elem_ty:ty,
         c_ty: $c_ty:expr,
+        c_val: $c_val:expr,
         new: $new:ident,
         empty: $empty:ident,
         uninit: $uninit:ident,
@@ -21,10 +22,8 @@ Read the documentation of [`", $c_ty, "`] to see more concrete examples.
 #    (assert_c! {
 # #include \"tests/wasmer.h\"
 #
-int main() {
+void example(", $c_ty, " x, ", $c_ty, " y) {
     // Create a vector of 2 `", $c_ty, "`.
-    ", $c_ty, " x;
-    ", $c_ty, " y;
     ", $c_ty, " items[2] = {x, y};
 
     ", stringify!($name), " vector;
@@ -36,6 +35,8 @@ int main() {
     // Free it.
     ", stringify!($delete), "(&vector);
 }
+#
+# int main() { example(", $c_val, ", ", $c_val, "); return 0; }
 #    })
 #    .success();
 # }
@@ -134,6 +135,8 @@ int main() {
 
     // Free it.
     ", stringify!($delete), "(&vector);
+
+    return 0;
 }
 #    })
 #    .success();
@@ -165,6 +168,8 @@ int main() {
 
     // Free it.
     ", stringify!($delete), "(&vector);
+
+    return 0;
 }
 #    })
 #    .success();
@@ -215,6 +220,11 @@ macro_rules! wasm_declare_vec {
                 name: [<$prefix _ $name _vec_t>],
                 ty: [<$prefix _ $name _t>],
                 c_ty: stringify!([<$prefix _ $name _t>]),
+                c_val: concat!("({ ",
+                    stringify!([<$prefix _ $name _t>]), " foo;\n",
+                    "memset(&foo, 0, sizeof(foo));\n",
+                    "foo;\n",
+                "})"),
                 new: [<$prefix _ $name _vec_new>],
                 empty: [<$prefix _ $name _vec_new_empty>],
                 uninit: [<$prefix _ $name _vec_new_uninitialized>],
@@ -236,6 +246,7 @@ macro_rules! wasm_declare_boxed_vec {
                 name: [<$prefix _ $name _vec_t>],
                 ty: Option<Box<[<$prefix _ $name _t>]>>,
                 c_ty: stringify!([<$prefix _ $name _t>] *),
+                c_val: "NULL",
                 new: [<$prefix _ $name _vec_new>],
                 empty: [<$prefix _ $name _vec_new_empty>],
                 uninit: [<$prefix _ $name _vec_new_uninitialized>],
diff --git a/lib/c-api/src/wasm_c_api/types/export.rs b/lib/c-api/src/wasm_c_api/types/export.rs
index 39d5ab674..a60ccf48b 100644
--- a/lib/c-api/src/wasm_c_api/types/export.rs
+++ b/lib/c-api/src/wasm_c_api/types/export.rs
@@ -5,7 +5,7 @@ use wasmer_api::ExportType;
 #[derive(Clone)]
 pub struct wasm_exporttype_t {
     name: wasm_name_t,
-    extern_type: Box<wasm_externtype_t>,
+    extern_type: wasm_externtype_t,
 }
 
 wasm_declare_boxed_vec!(exporttype);
@@ -18,7 +18,7 @@ pub extern "C" fn wasm_exporttype_new(
 ) -> Box<wasm_exporttype_t> {
     Box::new(wasm_exporttype_t {
         name: name.clone(),
-        extern_type,
+        extern_type: *extern_type,
     })
 }
 
@@ -29,7 +29,7 @@ pub extern "C" fn wasm_exporttype_name(export_type: &wasm_exporttype_t) -> &wasm
 
 #[no_mangle]
 pub extern "C" fn wasm_exporttype_type(export_type: &wasm_exporttype_t) -> &wasm_externtype_t {
-    export_type.extern_type.as_ref()
+    &export_type.extern_type
 }
 
 impl From<ExportType> for wasm_exporttype_t {
@@ -41,7 +41,7 @@ impl From<ExportType> for wasm_exporttype_t {
 impl From<&ExportType> for wasm_exporttype_t {
     fn from(other: &ExportType) -> Self {
         let name: wasm_name_t = other.name().to_string().into();
-        let extern_type: Box<wasm_externtype_t> = Box::new(other.ty().into());
+        let extern_type: wasm_externtype_t = other.ty().into();
 
         wasm_exporttype_t { name, extern_type }
     }
diff --git a/lib/c-api/src/wasm_c_api/types/global.rs b/lib/c-api/src/wasm_c_api/types/global.rs
index bdb9b7eb9..26342e428 100644
--- a/lib/c-api/src/wasm_c_api/types/global.rs
+++ b/lib/c-api/src/wasm_c_api/types/global.rs
@@ -8,12 +8,12 @@ use wasmer_api::{ExternType, GlobalType};
 #[derive(Debug, Clone)]
 pub(crate) struct WasmGlobalType {
     pub(crate) global_type: GlobalType,
-    content: Box<wasm_valtype_t>,
+    content: wasm_valtype_t,
 }
 
 impl WasmGlobalType {
     pub(crate) fn new(global_type: GlobalType) -> Self {
-        let content = Box::new(global_type.ty.into());
+        let content = global_type.ty.into();
 
         Self {
             global_type,
@@ -79,5 +79,5 @@ pub unsafe extern "C" fn wasm_globaltype_mutability(
 pub unsafe extern "C" fn wasm_globaltype_content(
     global_type: &wasm_globaltype_t,
 ) -> &wasm_valtype_t {
-    global_type.inner().content.as_ref()
+    &global_type.inner().content
 }
diff --git a/lib/c-api/src/wasm_c_api/types/import.rs b/lib/c-api/src/wasm_c_api/types/import.rs
index c2de86aed..5e075ece7 100644
--- a/lib/c-api/src/wasm_c_api/types/import.rs
+++ b/lib/c-api/src/wasm_c_api/types/import.rs
@@ -7,7 +7,7 @@ use wasmer_api::ImportType;
 pub struct wasm_importtype_t {
     module: wasm_name_t,
     name: wasm_name_t,
-    extern_type: Box<wasm_externtype_t>,
+    extern_type: wasm_externtype_t,
 }
 
 wasm_declare_boxed_vec!(importtype);
@@ -21,7 +21,7 @@ pub extern "C" fn wasm_importtype_new(
     Some(Box::new(wasm_importtype_t {
         name: *name?,
         module: *module?,
-        extern_type: extern_type?,
+        extern_type: *extern_type?,
     }))
 }
 
@@ -37,7 +37,7 @@ pub extern "C" fn wasm_importtype_name(import_type: &wasm_importtype_t) -> &wasm
 
 #[no_mangle]
 pub extern "C" fn wasm_importtype_type(import_type: &wasm_importtype_t) -> &wasm_externtype_t {
-    import_type.extern_type.as_ref()
+    &import_type.extern_type
 }
 
 #[no_mangle]
@@ -53,7 +53,7 @@ impl From<&ImportType> for wasm_importtype_t {
     fn from(other: &ImportType) -> Self {
         let module: wasm_name_t = other.module().to_string().into();
         let name: wasm_name_t = other.name().to_string().into();
-        let extern_type: Box<wasm_externtype_t> = Box::new(other.ty().into());
+        let extern_type: wasm_externtype_t = other.ty().into();
 
         wasm_importtype_t {
             module,
diff --git a/lib/c-api/src/wasm_c_api/types/memory.rs b/lib/c-api/src/wasm_c_api/types/memory.rs
index b98c16494..e60eb8459 100644
--- a/lib/c-api/src/wasm_c_api/types/memory.rs
+++ b/lib/c-api/src/wasm_c_api/types/memory.rs
@@ -4,18 +4,18 @@ use wasmer_api::{ExternType, MemoryType, Pages};
 #[derive(Debug, Clone)]
 pub(crate) struct WasmMemoryType {
     pub(crate) memory_type: MemoryType,
-    limits: Box<wasm_limits_t>,
+    limits: wasm_limits_t,
 }
 
 impl WasmMemoryType {
     pub(crate) fn new(memory_type: MemoryType) -> Self {
-        let limits = Box::new(wasm_limits_t {
+        let limits = wasm_limits_t {
             min: memory_type.minimum.0 as _,
             max: memory_type
                 .maximum
                 .map(|max| max.0 as _)
                 .unwrap_or(LIMITS_MAX_SENTINEL),
-        });
+        };
 
         Self {
             memory_type,
@@ -79,5 +79,5 @@ const LIMITS_MAX_SENTINEL: u32 = u32::max_value();
 
 #[no_mangle]
 pub unsafe extern "C" fn wasm_memorytype_limits(memory_type: &wasm_memorytype_t) -> &wasm_limits_t {
-    memory_type.inner().limits.as_ref()
+    &memory_type.inner().limits
 }
diff --git a/lib/c-api/src/wasm_c_api/types/table.rs b/lib/c-api/src/wasm_c_api/types/table.rs
index a17c3aef3..a3d74ee79 100644
--- a/lib/c-api/src/wasm_c_api/types/table.rs
+++ b/lib/c-api/src/wasm_c_api/types/table.rs
@@ -10,21 +10,21 @@ const LIMITS_MAX_SENTINEL: u32 = u32::max_value();
 
 #[derive(Debug, Clone)]
 pub(crate) struct WasmTableType {
-    pub(crate) table_type: TableType,
-    limits: Box<wasm_limits_t>,
-    content: Box<wasm_valtype_t>,
+    pub(crate) _table_type: TableType,
+    limits: wasm_limits_t,
+    content: wasm_valtype_t,
 }
 
 impl WasmTableType {
     pub(crate) fn new(table_type: TableType) -> Self {
-        let limits = Box::new(wasm_limits_t {
+        let limits = wasm_limits_t {
             min: table_type.minimum as _,
             max: table_type.maximum.unwrap_or(LIMITS_MAX_SENTINEL),
-        });
-        let content = Box::new(table_type.ty.into());
+        };
+        let content = table_type.ty.into();
 
         Self {
-            table_type,
+            _table_type: table_type,
             limits,
             content,
         }
@@ -79,12 +79,12 @@ pub unsafe extern "C" fn wasm_tabletype_new(
 
 #[no_mangle]
 pub unsafe extern "C" fn wasm_tabletype_limits(table_type: &wasm_tabletype_t) -> &wasm_limits_t {
-    table_type.inner().limits.as_ref()
+    &table_type.inner().limits
 }
 
 #[no_mangle]
 pub unsafe extern "C" fn wasm_tabletype_element(table_type: &wasm_tabletype_t) -> &wasm_valtype_t {
-    table_type.inner().content.as_ref()
+    &table_type.inner().content
 }
 
 #[no_mangle]
diff --git a/lib/c-api/src/wasm_c_api/unstable/module.rs b/lib/c-api/src/wasm_c_api/unstable/module.rs
index 9e85b2f85..81528369b 100644
--- a/lib/c-api/src/wasm_c_api/unstable/module.rs
+++ b/lib/c-api/src/wasm_c_api/unstable/module.rs
@@ -70,7 +70,7 @@ pub unsafe extern "C" fn wasmer_module_name(
         }
     };
 
-    *out = name.as_bytes().to_vec().into();
+    out.set_buffer(name.as_bytes().to_vec());
 }
 
 /// Unstable non-standard Wasmer-specific API to set the module's