clippy: add clippy::must_use_candidat

src/archive.rs

@@ -58,11 +58,13 @@ impl<'a> ArchiveEntry<'a> {
 
     /// Filename of the entry with a maximum of 100 characters (including the
     /// terminating NULL-byte).
+    #[must_use]
     pub const fn filename(&self) -> TarFormatString<{ POSIX_1003_MAX_FILENAME_LEN }> {
         self.filename
     }
 
     /// Data of the file.
+    #[must_use]
     pub const fn data(&self) -> &'a [u8] {
         self.data
     }
@@ -74,6 +76,7 @@ impl<'a> ArchiveEntry<'a> {
     }
 
     /// Filesize in bytes.
+    #[must_use]
     pub const fn size(&self) -> usize {
         self.size
     }
@@ -174,6 +177,7 @@ impl<'a> TarArchiveRef<'a> {
     }
 
     /// Creates an [`ArchiveEntryIterator`].
+    #[must_use]
     pub fn entries(&self) -> ArchiveEntryIterator {
         ArchiveEntryIterator::new(self.data)
     }
@@ -187,6 +191,7 @@ pub struct ArchiveHeaderIterator<'a> {
 }
 
 impl<'a> ArchiveHeaderIterator<'a> {
+    #[must_use]
     pub fn new(archive: &'a [u8]) -> Self {
         assert!(!archive.is_empty());
         assert_eq!(archive.len() % BLOCKSIZE, 0);

src/header.rs

@@ -146,6 +146,7 @@ pub enum TypeFlag {
 
 impl TypeFlag {
     /// Whether we have a regular file.
+    #[must_use]
     pub fn is_regular_file(self) -> bool {
         // Equivalent. See spec.
         self == Self::AREGTYPE || self == Self::REGTYPE
@@ -257,6 +258,7 @@ impl PosixHeader {
 
     /// A Tar archive is terminated, if an end-of-archive entry, which consists
     /// of two 512 blocks of zero bytes, is found.
+    #[must_use]
     pub fn is_zero_block(&self) -> bool {
         let ptr = self as *const Self as *const u8;
         let self_bytes = unsafe { core::slice::from_raw_parts(ptr, BLOCKSIZE) };

src/lib.rs

@@ -95,6 +95,7 @@ SOFTWARE.
     clippy::all,
     clippy::cargo,
     clippy::nursery,
+    clippy::must_use_candidate,
     // clippy::restriction,
     // clippy::pedantic
 )]

src/tar_format_types.rs

@@ -23,6 +23,7 @@ pub struct TarFormatString<const N: usize> {
 /// This string will be null terminated if it doesn't fill the entire array.
 impl<const N: usize> TarFormatString<N> {
     /// Constructor.
+    #[must_use]
     pub const fn new(bytes: [u8; N]) -> Self {
         if N == 0 {
             panic!("Array cannot be zero length");
@@ -31,12 +32,14 @@ impl<const N: usize> TarFormatString<N> {
     }
 
     /// True if the is string empty (ignoring NULL bytes).
+    #[must_use]
     pub const fn is_empty(&self) -> bool {
         self.bytes[0] == 0
     }
 
     /// Returns the length of the payload in bytes. This is either the full
     /// capacity `N` or the data until the first NULL byte.
+    #[must_use]
     pub fn size(&self) -> usize {
         memchr::memchr(0, &self.bytes).unwrap_or(N)
     }
@@ -121,6 +124,7 @@ impl<const N: usize, const R: u32> TarFormatNumber<N, R> {
     }
 
     /// Returns the underlying [`TarFormatString`].
+    #[must_use]
     pub const fn as_inner(&self) -> &TarFormatString<N> {
         &self.0
     }
@@ -157,6 +161,7 @@ impl<const N: usize> TarFormatDecimal<N> {
     }
 
     /// Returns the underlying [`TarFormatString`].
+    #[must_use]
     pub const fn as_inner(&self) -> &TarFormatString<N> {
         self.0.as_inner()
     }
@@ -171,6 +176,7 @@ impl<const N: usize> TarFormatOctal<N> {
     }
 
     /// Returns the underlying [`TarFormatString`].
+    #[must_use]
     pub const fn as_inner(&self) -> &TarFormatString<N> {
         self.0.as_inner()
     }