Allow unreachable_code for uncallable functions in WASM

src/libstd/sys/cloudabi/shims/fs.rs

@@ -251,6 +251,9 @@ pub fn rename(_old: &Path, _new: &Path) -> io::Result<()> {
     unsupported()
 }
 
+// `FilePermissions` is uninhabited in CloudABI, so this function is
+// uncallable (but necessary for the public interface).
+#[allow(unreachable_code)]
 pub fn set_perm(_p: &Path, perm: FilePermissions) -> io::Result<()> {
     match perm.0 {}
 }

src/libstd/sys/cloudabi/shims/pipe.rs

@@ -17,6 +17,9 @@ impl AnonPipe {
     }
 }
 
+// `AnonPipe` is uninhabited in CloudABI, so this function is
+// uncallable (but necessary for the public interface).
+#[allow(unreachable_code)]
 pub fn read2(p1: AnonPipe, _v1: &mut Vec<u8>, _p2: AnonPipe, _v2: &mut Vec<u8>) -> io::Result<()> {
     match p1.0 {}
 }

src/libstd/sys/sgx/fs.rs

@@ -253,6 +253,9 @@ pub fn rename(_old: &Path, _new: &Path) -> io::Result<()> {
     unsupported()
 }
 
+// `FilePermissions` is uninhabited in SGX, so this function is
+// uncallable (but necessary for the public interface).
+#[allow(unreachable_code)]
 pub fn set_perm(_p: &Path, perm: FilePermissions) -> io::Result<()> {
     match perm.0 {}
 }

src/libstd/sys/sgx/pipe.rs

@@ -17,6 +17,9 @@ impl AnonPipe {
     }
 }
 
+// `AnonPipe` is uninhabited in SGX, so this function is
+// uncallable (but necessary for the public interface).
+#[allow(unreachable_code)]
 pub fn read2(p1: AnonPipe,
              _v1: &mut Vec<u8>,
              _p2: AnonPipe,

src/libstd/sys/wasm/fs.rs

@@ -253,6 +253,9 @@ pub fn rename(_old: &Path, _new: &Path) -> io::Result<()> {
     unsupported()
 }
 
+// `FilePermissions` is uninhabited in WASM, so this function is
+// uncallable (but necessary for the public interface).
+#[allow(unreachable_code)]
 pub fn set_perm(_p: &Path, perm: FilePermissions) -> io::Result<()> {
     match perm.0 {}
 }

src/libstd/sys/wasm/pipe.rs

@@ -17,6 +17,9 @@ impl AnonPipe {
     }
 }
 
+// `AnonPipe` is uninhabited in WASM, so this function is
+// uncallable (but necessary for the public interface).
+#[allow(unreachable_code)]
 pub fn read2(p1: AnonPipe,
              _v1: &mut Vec<u8>,
              _p2: AnonPipe,