Make ast no_std compatible

Author: coolreader18

ast/Cargo.toml

@@ -5,4 +5,4 @@ authors = ["RustPython Team"]
 edition = "2018"
 
 [dependencies]
-num-bigint = "0.3"
+num-bigint = { version = "0.3", default-features = false }

ast/src/ast.rs

@@ -5,6 +5,7 @@
 //! location of the node.
 
 pub use crate::location::Location;
+use alloc::{boxed::Box, string::String, vec::Vec};
 use num_bigint::BigInt;
 
 #[allow(clippy::large_enum_variant)]

ast/src/lib.rs

@@ -1,3 +1,7 @@
+#![no_std]
+
+extern crate alloc;
+
 mod ast;
 mod location;
 

ast/src/location.rs

@@ -1,6 +1,6 @@
 //! Datatypes to support source location information.
 
-use std::fmt;
+use core::fmt;
 
 /// A location somewhere in the sourcecode.
 #[derive(Clone, Copy, Debug, Default, PartialEq)]