impl From<anyhow::Error> for Trap (#1753)

* From<anyhow::Error> for Trap

* Add TrapReason::Error

* wasmtime: Improve Error to Trap conversion

* Remove Trap::message

tests/all/func.rs

@@ -181,7 +181,7 @@ fn trap_smoke() -> Result<()> {
     let store = Store::default();
     let f = Func::wrap(&store, || -> Result<(), Trap> { Err(Trap::new("test")) });
     let err = f.call(&[]).unwrap_err().downcast::<Trap>()?;
-    assert_eq!(err.message(), "test");
+    assert!(err.to_string().contains("test"));
     assert!(err.i32_exit_status().is_none());
     Ok(())
 }
@@ -203,7 +203,7 @@ fn trap_import() -> Result<()> {
     .err()
     .unwrap()
     .downcast::<Trap>()?;
-    assert_eq!(trap.message(), "foo");
+    assert!(trap.to_string().contains("foo"));
     Ok(())
 }
 
@@ -397,9 +397,8 @@ fn func_write_nothing() -> anyhow::Result<()> {
     let ty = FuncType::new(Box::new([]), Box::new([ValType::I32]));
     let f = Func::new(&store, ty, |_, _, _| Ok(()));
     let err = f.call(&[]).unwrap_err().downcast::<Trap>()?;
-    assert_eq!(
-        err.message(),
-        "function attempted to return an incompatible value"
-    );
+    assert!(err
+        .to_string()
+        .contains("function attempted to return an incompatible value"));
     Ok(())
 }