Merge #467

467: feat(runtime-c-api) `wasmer_instantiate` raises the source error r=syrusakbary a=Hywan

Instead of returning only “error instanting”, `wasmer_instantiate` can
return the real error message.

Co-authored-by: Ivan Enderlin <ivan.enderlin@hoa-project.net>
Co-authored-by: Syrus Akbary <me@syrusakbary.com>

CHANGELOG.md

@@ -6,6 +6,7 @@ Blocks of changes will separated by version increments.
 
 ## **[Unreleased]**
 
+- [#467](https://github.com/wasmerio/wasmer/pull/467) `wasmer_instantiate` returns better error messages in the runtime C API
 - [#463](https://github.com/wasmerio/wasmer/pull/463) Fix bug in WASI path_open allowing one level above preopened dir to be accessed
 - [#461](https://github.com/wasmerio/wasmer/pull/461) Prevent passing negative lengths in various places in the runtime C API
 - [#459](https://github.com/wasmerio/wasmer/pull/459) Add monotonic and real time clocks for wasi on windows

lib/runtime-c-api/src/instance.rs

@@ -99,12 +99,8 @@ pub unsafe extern "C" fn wasmer_instantiate(
     let result = wasmer_runtime::instantiate(bytes, &import_object);
     let new_instance = match result {
         Ok(instance) => instance,
-        Err(_error) => {
-            // TODO the trait bound `wasmer_runtime::error::Error: std::error::Error` is not satisfied
-            //update_last_error(error);
-            update_last_error(CApiError {
-                msg: "error instantiating".to_string(),
-            });
+        Err(error) => {
+            update_last_error(error);
             return wasmer_result_t::WASMER_ERROR;
         }
     };