[Rust] use core:error:Error unconditionally

rust/flatbuffers/Cargo.toml

@@ -9,7 +9,7 @@ homepage = "https://google.github.io/flatbuffers/"
 repository = "https://github.com/google/flatbuffers"
 keywords = ["flatbuffers", "serialization", "zero-copy"]
 categories = ["encoding", "data-structures", "memory-management"]
-rust = "1.51"
+rust-version = "1.81"
 
 [features]
 default = ["std"]

rust/flatbuffers/src/builder.rs

@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-#[cfg(not(feature = "std"))]
 use alloc::{vec, vec::Vec};
 use core::cmp::max;
 use core::convert::Infallible;

rust/flatbuffers/src/lib.rs

@@ -28,10 +28,6 @@
 //! At this time, to generate Rust code, you will need the latest `master` version of `flatc`, available from here: <https://github.com/google/flatbuffers>
 //! (On OSX, you can install FlatBuffers from `HEAD` with the Homebrew package manager.)
 
-#![cfg_attr(not(feature = "std"), no_std)]
-#![cfg_attr(all(nightly, not(feature = "std")), feature(error_in_core))]
-
-#[cfg(not(feature = "std"))]
 extern crate alloc;
 
 mod array;

rust/flatbuffers/src/verifier.rs

@@ -1,20 +1,11 @@
 use crate::follow::Follow;
 use crate::{ForwardsUOffset, SOffsetT, SkipSizePrefix, UOffsetT, VOffsetT, Vector, SIZE_UOFFSET};
-#[cfg(not(feature = "std"))]
+use alloc::borrow::Cow;
 use alloc::vec::Vec;
+use core::error::Error;
 use core::ops::Range;
 use core::option::Option;
 
-#[cfg(not(feature = "std"))]
-use alloc::borrow::Cow;
-#[cfg(feature = "std")]
-use std::borrow::Cow;
-
-#[cfg(all(nightly, not(feature = "std")))]
-use core::error::Error;
-#[cfg(feature = "std")]
-use std::error::Error;
-
 /// Traces the location of data errors. Not populated for Dos detecting errors.
 /// Useful for MissingRequiredField and Utf8Error in particular, though
 /// the other errors should not be producible by correct flatbuffers implementations.
@@ -86,7 +77,6 @@ pub enum InvalidFlatbuffer {
     DepthLimitReached,
 }
 
-#[cfg(any(nightly, feature = "std"))]
 impl Error for InvalidFlatbuffer {
     fn source(&self) -> Option<&(dyn Error + 'static)> {
         if let InvalidFlatbuffer::Utf8Error { error: source, .. } = self {