Always allow dead_code/unused_import warnings in wasmtime

crates/wasmtime/src/lib.rs

@@ -281,12 +281,6 @@
 #![doc(test(attr(deny(warnings))))]
 #![doc(test(attr(allow(dead_code, unused_variables, unused_mut))))]
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
-// NB: this list is currently being burned down to remove all features listed
-// here to get warnings in all configurations of Wasmtime.
-#![cfg_attr(
-    any(not(feature = "runtime"), not(feature = "std")),
-    allow(dead_code, unused_imports)
-)]
 // Allow broken links when the default features is disabled because most of our
 // documentation is written for the "one build" of the `main` branch which has
 // most features enabled. This will present warnings in stripped-down doc builds

crates/wasmtime/src/runtime/vm/mmap.rs

@@ -5,6 +5,7 @@ use super::HostAlignedByteCount;
 use crate::prelude::*;
 use crate::runtime::vm::sys::{mmap, vm::MemoryImageSource};
 use alloc::sync::Arc;
+use core::marker;
 use core::ops::Range;
 use core::ptr::NonNull;
 #[cfg(feature = "std")]
@@ -58,7 +59,9 @@ pub struct UnalignedLength {
 #[derive(Debug)]
 pub struct Mmap<T> {
     sys: mmap::Mmap,
+    #[cfg(feature = "std")]
     data: T,
+    _marker: marker::PhantomData<T>,
 }
 
 impl Mmap<AlignedLength> {
@@ -86,19 +89,25 @@ impl Mmap<AlignedLength> {
         if mapping_size.is_zero() {
             Ok(Mmap {
                 sys: mmap::Mmap::new_empty(),
+                #[cfg(feature = "std")]
                 data: AlignedLength {},
+                _marker: marker::PhantomData,
             })
         } else if accessible_size == mapping_size {
             Ok(Mmap {
                 sys: mmap::Mmap::new(mapping_size)
                     .context(format!("mmap failed to allocate {mapping_size:#x} bytes"))?,
+                #[cfg(feature = "std")]
                 data: AlignedLength {},
+                _marker: marker::PhantomData,
             })
         } else {
             let result = Mmap {
                 sys: mmap::Mmap::reserve(mapping_size)
                     .context(format!("mmap failed to reserve {mapping_size:#x} bytes"))?,
+                #[cfg(feature = "std")]
                 data: AlignedLength {},
+                _marker: marker::PhantomData,
             };
             if !accessible_size.is_zero() {
                 // SAFETY: result was just created and is not in use.
@@ -121,10 +130,9 @@ impl Mmap<AlignedLength> {
     pub fn into_unaligned(self) -> Mmap<UnalignedLength> {
         Mmap {
             sys: self.sys,
-            data: UnalignedLength {
-                #[cfg(feature = "std")]
-                file: None,
-            },
+            #[cfg(feature = "std")]
+            data: UnalignedLength { file: None },
+            _marker: marker::PhantomData,
         }
     }
 
@@ -207,6 +215,7 @@ impl Mmap<UnalignedLength> {
         Ok(Mmap {
             sys,
             data: UnalignedLength { file: Some(file) },
+            _marker: marker::PhantomData,
         })
     }
 

crates/wasmtime/src/runtime/vm/mmap_vec.rs

@@ -5,12 +5,11 @@ use crate::runtime::vm::send_sync_ptr::SendSyncPtr;
 use crate::runtime::vm::{mmap::UnalignedLength, Mmap};
 #[cfg(not(has_virtual_memory))]
 use alloc::alloc::Layout;
-use alloc::sync::Arc;
 use core::ops::{Deref, Range};
 #[cfg(not(has_virtual_memory))]
 use core::ptr::NonNull;
 #[cfg(feature = "std")]
-use std::fs::File;
+use std::{fs::File, sync::Arc};
 
 /// A type which prefers to store backing memory in an OS-backed memory mapping
 /// but can fall back to the regular memory allocator as well.