refactor(cust_raw): Add must_use attrbuites on result/error types.

CUDA libraries have different result types (`CUresult`, `cudaError_t`, etc.) that must be checked after calling the function. This change adds `must_use` attribute on those types and functions that return that type when generating the bindings. This also fixes the warnings caused by this in places where the result type was not checked by either checking the result type, or ignore the value.

Author: jorge-ortega

crates/blastoff/src/context.rs

@@ -340,7 +340,7 @@ impl CublasContext {
 impl Drop for CublasContext {
     fn drop(&mut self) {
         unsafe {
-            cublas_sys::cublasDestroy(self.raw);
+            let _ = cublas_sys::cublasDestroy(self.raw);
         }
     }
 }

crates/cust/src/context/legacy.rs

@@ -372,7 +372,7 @@ impl Drop for Context {
 
         unsafe {
             let inner = mem::replace(&mut self.inner, ptr::null_mut());
-            driver_sys::cuCtxDestroy(inner);
+            let _ = driver_sys::cuCtxDestroy(inner);
         }
     }
 }

crates/cust/src/context/mod.rs

@@ -197,7 +197,7 @@ impl Context {
             driver_sys::cuDevicePrimaryCtxRetain(inner.as_mut_ptr(), device.as_raw())
                 .to_result()?;
             let inner = inner.assume_init();
-            driver_sys::cuCtxSetCurrent(inner);
+            driver_sys::cuCtxSetCurrent(inner).to_result()?;
             Ok(Self {
                 inner,
                 device: device.as_raw(),
@@ -316,7 +316,7 @@ impl Drop for Context {
 
         unsafe {
             self.inner = ptr::null_mut();
-            driver_sys::cuDevicePrimaryCtxRelease(self.device);
+            let _ = driver_sys::cuDevicePrimaryCtxRelease(self.device);
         }
     }
 }

crates/cust/src/event.rs

@@ -347,7 +347,9 @@ impl Event {
 
 impl Drop for Event {
     fn drop(&mut self) {
-        unsafe { cuEventDestroy(self.0) };
+        unsafe {
+            let _ = cuEventDestroy(self.0);
+        };
     }
 }
 

crates/cust/src/link.rs

@@ -137,6 +137,8 @@ impl Linker {
 
 impl Drop for Linker {
     fn drop(&mut self) {
-        unsafe { driver_sys::cuLinkDestroy(self.raw) };
+        unsafe {
+            let _ = driver_sys::cuLinkDestroy(self.raw);
+        };
     }
 }

crates/cust/src/memory/array.rs

@@ -867,7 +867,9 @@ impl std::fmt::Debug for ArrayObject {
 
 impl Drop for ArrayObject {
     fn drop(&mut self) {
-        unsafe { driver_sys::cuArrayDestroy(self.handle) };
+        unsafe {
+            let _ = driver_sys::cuArrayDestroy(self.handle);
+        };
     }
 }
 

crates/cust/src/module.rs

@@ -491,7 +491,7 @@ impl Drop for Module {
         unsafe {
             // No choice but to panic if this fails...
             let module = mem::replace(&mut self.inner, ptr::null_mut());
-            driver_sys::cuModuleUnload(module);
+            let _ = driver_sys::cuModuleUnload(module);
         }
     }
 }

crates/cust/src/stream.rs

@@ -344,7 +344,7 @@ impl Drop for Stream {
         unsafe {
             let inner = mem::replace(&mut self.inner, ptr::null_mut());
 
-            driver_sys::cuStreamDestroy(inner);
+            let _ = driver_sys::cuStreamDestroy(inner);
         }
     }
 }

crates/cust/src/surface.rs

@@ -30,7 +30,7 @@ impl Drop for Surface {
                 }
             }
 
-            cuSurfObjectDestroy(self.handle);
+            let _ = cuSurfObjectDestroy(self.handle);
         }
     }
 }

crates/cust/src/texture.rs

@@ -415,7 +415,7 @@ impl Drop for Texture {
                 }
             }
 
-            cuTexObjectDestroy(self.handle);
+            let _ = cuTexObjectDestroy(self.handle);
         }
     }
 }