Explicit transmute types

src/hooks/dx11.rs

@@ -133,8 +133,12 @@ fn get_target_addrs() -> DXGISwapChainPresentType {
 
     let swap_chain = p_swap_chain.unwrap();
 
-    let present_ptr: DXGISwapChainPresentType =
-        unsafe { mem::transmute(swap_chain.vtable().Present) };
+    let present_ptr: DXGISwapChainPresentType = unsafe {
+        mem::transmute::<
+            unsafe extern "system" fn(*mut c_void, u32, u32) -> HRESULT,
+            DXGISwapChainPresentType,
+        >(swap_chain.vtable().Present)
+    };
 
     present_ptr
 }
@@ -167,7 +171,9 @@ impl ImguiDx11Hooks {
 
         RENDER_LOOP.get_or_init(|| Box::new(t));
         TRAMPOLINES.get_or_init(|| Trampolines {
-            dxgi_swap_chain_present: mem::transmute(hook_present.trampoline()),
+            dxgi_swap_chain_present: mem::transmute::<*mut c_void, DXGISwapChainPresentType>(
+                hook_present.trampoline(),
+            ),
         });
 
         Self([hook_present])

src/hooks/dx12.rs

@@ -276,9 +276,17 @@ impl ImguiDx12Hooks {
         RENDER_LOOP.get_or_init(|| Box::new(t));
 
         TRAMPOLINES.get_or_init(|| Trampolines {
-            dxgi_swap_chain_present: mem::transmute(hook_present.trampoline()),
-            dxgi_swap_chain_resize_buffers: mem::transmute(hook_resize_buffers.trampoline()),
-            d3d12_command_queue_execute_command_lists: mem::transmute(hook_cqecl.trampoline()),
+            dxgi_swap_chain_present: mem::transmute::<*mut c_void, DXGISwapChainPresentType>(
+                hook_present.trampoline(),
+            ),
+            dxgi_swap_chain_resize_buffers: mem::transmute::<
+                *mut c_void,
+                DXGISwapChainResizeBuffersType,
+            >(hook_resize_buffers.trampoline()),
+            d3d12_command_queue_execute_command_lists: mem::transmute::<
+                *mut c_void,
+                D3D12CommandQueueExecuteCommandListsType,
+            >(hook_cqecl.trampoline()),
         });
 
         Self([hook_present, hook_resize_buffers, hook_cqecl])

src/hooks/dx9.rs

@@ -151,7 +151,24 @@ fn get_target_addrs() -> (Dx9PresentType, Dx9ResetType) {
     let present_ptr = device.vtable().Present;
     let reset_ptr = device.vtable().Reset;
 
-    unsafe { (mem::transmute(present_ptr), mem::transmute(reset_ptr)) }
+    unsafe {
+        (
+            mem::transmute::<
+                unsafe extern "system" fn(
+                    *mut c_void,
+                    *const RECT,
+                    *const RECT,
+                    HWND,
+                    *const RGNDATA,
+                ) -> HRESULT,
+                Dx9PresentType,
+            >(present_ptr),
+            mem::transmute::<
+                unsafe extern "system" fn(*mut c_void, *mut D3DPRESENT_PARAMETERS) -> HRESULT,
+                Dx9ResetType,
+            >(reset_ptr),
+        )
+    }
 }
 
 /// Hooks for DirectX 9.
@@ -182,8 +199,8 @@ impl ImguiDx9Hooks {
 
         RENDER_LOOP.get_or_init(|| Box::new(t));
         TRAMPOLINES.get_or_init(|| Trampolines {
-            dx9_present: mem::transmute(hook_present.trampoline()),
-            dx9_reset: mem::transmute(hook_reset.trampoline()),
+            dx9_present: mem::transmute::<*mut c_void, Dx9PresentType>(hook_present.trampoline()),
+            dx9_reset: mem::transmute::<*mut c_void, Dx9ResetType>(hook_reset.trampoline()),
         });
 
         Self([hook_present, hook_reset])

src/hooks/opengl3.rs

@@ -1,6 +1,6 @@
 //! Hooks for OpenGL 3.
 
-use std::ffi::CString;
+use std::ffi::{c_void, CString};
 use std::mem;
 use std::sync::OnceLock;
 
@@ -86,7 +86,9 @@ unsafe fn get_opengl_wglswapbuffers_addr() -> OpenGl32wglSwapBuffersType {
     let wglswapbuffers_func =
         GetProcAddress(opengl32module, PCSTR(wglswapbuffers.as_ptr() as *mut _)).unwrap();
 
-    mem::transmute(wglswapbuffers_func)
+    mem::transmute::<unsafe extern "system" fn() -> isize, OpenGl32wglSwapBuffersType>(
+        wglswapbuffers_func,
+    )
 }
 
 /// Hooks for OpenGL 3.
@@ -119,7 +121,7 @@ impl ImguiOpenGl3Hooks {
         // Initialize the render loop and store detours
         RENDER_LOOP.get_or_init(move || Box::new(t));
         TRAMPOLINES.get_or_init(|| Trampolines {
-            opengl32_wgl_swap_buffers: std::mem::transmute(
+            opengl32_wgl_swap_buffers: mem::transmute::<*mut c_void, OpenGl32wglSwapBuffersType>(
                 hook_opengl_wgl_swap_buffers.trampoline(),
             ),
         });

src/inject.rs

@@ -1,5 +1,6 @@
 //! Facilities for injecting compiled DLLs into target processes.
 
+use std::ffi::c_void;
 use std::mem::{self, size_of};
 use std::path::PathBuf;
 
@@ -58,7 +59,7 @@ impl Process {
             WriteProcessMemory(
                 self.0,
                 dll_path_buf,
-                dll_path.as_ptr() as *const std::ffi::c_void,
+                dll_path.as_ptr() as *const c_void,
                 (MAX_PATH as usize) * size_of::<u16>(),
                 Some(&mut bytes_written),
             )
@@ -71,7 +72,12 @@ impl Process {
                 self.0,
                 None,
                 0,
-                Some(std::mem::transmute(proc_addr)),
+                proc_addr.map(|proc_addr| {
+                    mem::transmute::<
+                        unsafe extern "system" fn() -> isize,
+                        unsafe extern "system" fn(*mut c_void) -> u32,
+                    >(proc_addr)
+                }),
                 Some(dll_path_buf),
                 0,
                 None,

src/renderer/backend/opengl3.rs

@@ -23,7 +23,12 @@ mod gl {
         clippy::too_many_arguments,
         clippy::unused_unit,
         clippy::upper_case_acronyms,
-        clippy::manual_non_exhaustive
+        clippy::manual_non_exhaustive,
+
+        // We support stable but lint on nightly. The following lint isn't available on stable,
+        // so allow `unknown_lints`.
+        unknown_lints,
+        clippy::missing_transmute_annotations
     )]
 
     include!(concat!(env!("OUT_DIR"), "/gl_bindings.rs"));

src/renderer/pipeline.rs

@@ -65,7 +65,16 @@ impl<T: RenderEngine> Pipeline<T> {
         }
 
         let wnd_proc = unsafe {
-            mem::transmute(SetWindowLongPtrA(hwnd, GWLP_WNDPROC, pipeline_wnd_proc as usize as _))
+            #[cfg(target_arch = "x86")]
+            type SwlpRet = i32;
+            #[cfg(target_arch = "x86_64")]
+            type SwlpRet = isize;
+
+            mem::transmute::<SwlpRet, WndProcType>(SetWindowLongPtrA(
+                hwnd,
+                GWLP_WNDPROC,
+                pipeline_wnd_proc as usize as _,
+            ))
         };
 
         let (tx, rx) = mpsc::channel();