update no_std config

crates/roc_std/src/lib.rs

@@ -1,5 +1,5 @@
+#![no_std]
 #![crate_type = "lib"]
-#![cfg_attr(feature = "no_std", no_std)]
 
 use arrayvec::ArrayString;
 use core::cmp::Ordering;
@@ -365,7 +365,7 @@ impl RocDec {
     }
 
     fn to_str_helper(self, string: &mut ArrayString<{ Self::MAX_STR_LENGTH }>) -> &str {
-        use std::fmt::Write;
+        use core::fmt::Write;
 
         if self.as_i128() == 0 {
             return "0";

crates/roc_std/src/roc_list.rs

@@ -7,11 +7,11 @@ use core::{
     fmt::Debug,
     hash::Hash,
     intrinsics::copy_nonoverlapping,
+    iter::FromIterator,
     mem::{self, ManuallyDrop},
     ops::Deref,
     ptr::{self, NonNull},
 };
-use std::iter::FromIterator;
 
 use crate::{roc_alloc, roc_dealloc, roc_realloc, storage::Storage};
 
@@ -474,7 +474,7 @@ where
 
 impl<'a, T> IntoIterator for &'a RocList<T> {
     type Item = &'a T;
-    type IntoIter = std::slice::Iter<'a, T>;
+    type IntoIter = core::slice::Iter<'a, T>;
 
     fn into_iter(self) -> Self::IntoIter {
         self.as_slice().iter()
@@ -529,7 +529,7 @@ impl<T> Drop for IntoIter<T> {
 }
 
 impl<T: Hash> Hash for RocList<T> {
-    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
         // This is the same as Rust's Vec implementation, which
         // just delegates to the slice implementation. It's a bit surprising
         // that Hash::hash_slice doesn't automatically incorporate the length,
@@ -551,7 +551,7 @@ impl<T: Clone> FromIterator<T> for RocList<T> {
     {
         let iter = into.into_iter();
 
-        if std::mem::size_of::<T>() == 0 {
+        if core::mem::size_of::<T>() == 0 {
             let count = iter.count();
             return Self {
                 elements: Some(Self::elems_with_capacity(count)),

crates/roc_std/src/roc_str.rs

@@ -10,8 +10,8 @@ use core::{
     ptr,
 };
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
-use std::ffi::{CStr, CString};
+use core::ffi::{CStr, CString};
 
 use crate::RocList;
 
@@ -527,7 +527,7 @@ impl Deref for RocStr {
 }
 
 /// This can fail because a CStr may contain invalid UTF-8 characters
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 impl TryFrom<&CStr> for RocStr {
     type Error = core::str::Utf8Error;
 
@@ -537,7 +537,7 @@ impl TryFrom<&CStr> for RocStr {
 }
 
 /// This can fail because a CString may contain invalid UTF-8 characters
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 impl TryFrom<CString> for RocStr {
     type Error = core::str::Utf8Error;
 

crates/roc_std/src/storage.rs

@@ -8,7 +8,7 @@ use core::num::NonZeroIsize;
 const REFCOUNT_1: NonZeroIsize = unsafe { NonZeroIsize::new_unchecked(isize::MIN) };
 
 const _ASSERT_STORAGE_SIZE: () =
-    assert!(std::mem::size_of::<isize>() == std::mem::size_of::<Storage>());
+    assert!(core::mem::size_of::<isize>() == core::mem::size_of::<Storage>());
 
 #[derive(Clone, Copy, Debug)]
 pub enum Storage {