aya: impl From<obj::InvalidMapTypeError> for MapTypeError

aya/src/bpf.rs

@@ -704,12 +704,8 @@ impl<'a> BpfLoader<'a> {
 }
 
 fn parse_map(data: (String, MapData)) -> Result<(String, Map), BpfError> {
-    let name = data.0;
-    let map = data.1;
-    let map_type =
-        bpf_map_type::try_from(map.obj.map_type()).map_err(|e| MapError::InvalidMapType {
-            map_type: e.map_type,
-        })?;
+    let (name, map) = data;
+    let map_type = bpf_map_type::try_from(map.obj.map_type()).map_err(MapError::from)?;
     let map = match map_type {
         BPF_MAP_TYPE_ARRAY => Map::Array(map),
         BPF_MAP_TYPE_PERCPU_ARRAY => Map::PerCpuArray(map),

aya/src/maps/mod.rs

@@ -50,6 +50,7 @@ use std::{
 use crate::util::KernelVersion;
 use libc::{getrlimit, rlimit, RLIMIT_MEMLOCK, RLIM_INFINITY};
 use log::warn;
+use obj::maps::InvalidMapTypeError;
 use thiserror::Error;
 
 use crate::{
@@ -192,6 +193,16 @@ pub enum MapError {
     },
 }
 
+// Note that this is not just derived using #[from] because InvalidMapTypeError cannot implement
+// Error due the the fact that aya-obj is nostd and error_in_core is not stabilized
+// (https://github.com/rust-lang/rust/issues/103765).
+impl From<InvalidMapTypeError> for MapError {
+    fn from(e: InvalidMapTypeError) -> Self {
+        let InvalidMapTypeError { map_type } = e;
+        MapError::InvalidMapType { map_type }
+    }
+}
+
 /// A map file descriptor.
 pub struct MapFd(RawFd);