clippy::must_use_candidate

libsqlite3-sys/src/error.rs

@@ -63,6 +63,7 @@ pub struct Error {
 }
 
 impl Error {
+    #[must_use]
     pub fn new(result_code: c_int) -> Error {
         let code = match result_code & 0xff {
             super::SQLITE_INTERNAL => ErrorCode::InternalMalfunction,
@@ -192,6 +193,7 @@ const SQLITE_WARNING_AUTOINDEX: c_int = SQLITE_WARNING | (1 << 8);
 
 const SQLITE_AUTH_USER: c_int = super::SQLITE_AUTH | (1 << 8);
 
+#[must_use]
 pub fn code_to_str(code: c_int) -> &'static str {
     match code {
         super::SQLITE_OK        => "Successful result",

libsqlite3-sys/src/lib.rs

@@ -12,10 +12,12 @@ use std::mem;
 
 mod error;
 
+#[must_use]
 pub fn SQLITE_STATIC() -> sqlite3_destructor_type {
     None
 }
 
+#[must_use]
 pub fn SQLITE_TRANSIENT() -> sqlite3_destructor_type {
     Some(unsafe { mem::transmute(-1isize) })
 }

src/backup.rs

@@ -231,6 +231,7 @@ impl Backup<'_, '_> {
     /// Gets the progress of the backup as of the last call to
     /// [`step`](Backup::step).
     #[inline]
+    #[must_use]
     pub fn progress(&self) -> Progress {
         unsafe {
             Progress {

src/blob/mod.rs

@@ -265,12 +265,14 @@ impl Blob<'_> {
 
     /// Return the size in bytes of the BLOB.
     #[inline]
+    #[must_use]
     pub fn size(&self) -> i32 {
         unsafe { ffi::sqlite3_blob_bytes(self.blob) }
     }
 
     /// Return the current size in bytes of the BLOB.
     #[inline]
+    #[must_use]
     pub fn len(&self) -> usize {
         use std::convert::TryInto;
         self.size().try_into().unwrap()
@@ -278,6 +280,7 @@ impl Blob<'_> {
 
     /// Return true if the BLOB is empty.
     #[inline]
+    #[must_use]
     pub fn is_empty(&self) -> bool {
         self.size() == 0
     }

src/column.rs

@@ -12,12 +12,14 @@ pub struct Column<'stmt> {
 impl Column<'_> {
     /// Returns the name of the column.
     #[inline]
+    #[must_use]
     pub fn name(&self) -> &str {
         self.name
     }
 
     /// Returns the type of the column (`None` for expression).
     #[inline]
+    #[must_use]
     pub fn decl_type(&self) -> Option<&str> {
         self.decl_type
     }

src/functions.rs

@@ -114,12 +114,14 @@ pub struct Context<'a> {
 impl Context<'_> {
     /// Returns the number of arguments to the function.
     #[inline]
+    #[must_use]
     pub fn len(&self) -> usize {
         self.args.len()
     }
 
     /// Returns `true` when there is no argument.
     #[inline]
+    #[must_use]
     pub fn is_empty(&self) -> bool {
         self.args.is_empty()
     }
@@ -157,6 +159,7 @@ impl Context<'_> {
     /// Will panic if `idx` is greater than or equal to
     /// [`self.len()`](Context::len).
     #[inline]
+    #[must_use]
     pub fn get_raw(&self, idx: usize) -> ValueRef<'_> {
         let arg = self.args[idx];
         unsafe { ValueRef::from_value(arg) }

src/row.rs

@@ -80,6 +80,7 @@ impl<'stmt> Rows<'stmt> {
     }
 
     /// Give access to the underlying statement
+    #[must_use]
     pub fn as_ref(&self) -> Option<&Statement<'stmt>> {
         self.stmt
     }

src/transaction.rs

@@ -169,6 +169,7 @@ impl Transaction<'_> {
     /// Get the current setting for what happens to the transaction when it is
     /// dropped.
     #[inline]
+    #[must_use]
     pub fn drop_behavior(&self) -> DropBehavior {
         self.drop_behavior
     }
@@ -296,6 +297,7 @@ impl Savepoint<'_> {
     /// Get the current setting for what happens to the savepoint when it is
     /// dropped.
     #[inline]
+    #[must_use]
     pub fn drop_behavior(&self) -> DropBehavior {
         self.drop_behavior
     }

src/types/value.rs

@@ -129,6 +129,7 @@ where
 impl Value {
     /// Returns SQLite fundamental datatype.
     #[inline]
+    #[must_use]
     pub fn data_type(&self) -> Type {
         match *self {
             Value::Null => Type::Null,

src/types/value_ref.rs

@@ -22,6 +22,7 @@ pub enum ValueRef<'a> {
 impl ValueRef<'_> {
     /// Returns SQLite fundamental datatype.
     #[inline]
+    #[must_use]
     pub fn data_type(&self) -> Type {
         match *self {
             ValueRef::Null => Type::Null,

src/version.rs

@@ -6,6 +6,7 @@ use std::ffi::CStr;
 ///
 /// See [`sqlite3_libversion_number()`](https://www.sqlite.org/c3ref/libversion.html).
 #[inline]
+#[must_use]
 pub fn version_number() -> i32 {
     unsafe { ffi::sqlite3_libversion_number() }
 }
@@ -14,6 +15,7 @@ pub fn version_number() -> i32 {
 ///
 /// See [`sqlite3_libversion()`](https://www.sqlite.org/c3ref/libversion.html).
 #[inline]
+#[must_use]
 pub fn version() -> &'static str {
     let cstr = unsafe { CStr::from_ptr(ffi::sqlite3_libversion()) };
     cstr.to_str()

src/vtab/mod.rs

@@ -87,6 +87,7 @@ const ZERO_MODULE: ffi::sqlite3_module = unsafe {
 /// Create a read-only virtual table implementation.
 ///
 /// Step 2 of [Creating New Virtual Table Implementations](https://sqlite.org/vtab.html#creating_new_virtual_table_implementations).
+#[must_use]
 pub fn read_only_module<'vtab, T: CreateVTab<'vtab>>() -> &'static Module<'vtab, T> {
     // The xConnect and xCreate methods do the same thing, but they must be
     // different so that the virtual table is not an eponymous virtual table.
@@ -126,6 +127,7 @@ pub fn read_only_module<'vtab, T: CreateVTab<'vtab>>() -> &'static Module<'vtab,
 /// Create an eponymous only virtual table implementation.
 ///
 /// Step 2 of [Creating New Virtual Table Implementations](https://sqlite.org/vtab.html#creating_new_virtual_table_implementations).
+#[must_use]
 pub fn eponymous_only_module<'vtab, T: VTab<'vtab>>() -> &'static Module<'vtab, T> {
     // A virtual table is eponymous if its xCreate method is the exact same function
     // as the xConnect method For eponymous-only virtual tables, the xCreate
@@ -326,6 +328,7 @@ impl IndexInfo {
 
     /// Record WHERE clause constraints.
     #[inline]
+    #[must_use]
     pub fn constraints(&self) -> IndexConstraintIter<'_> {
         let constraints =
             unsafe { slice::from_raw_parts((*self.0).aConstraint, (*self.0).nConstraint as usize) };
@@ -336,6 +339,7 @@ impl IndexInfo {
 
     /// Information about the ORDER BY clause.
     #[inline]
+    #[must_use]
     pub fn order_bys(&self) -> OrderByIter<'_> {
         let order_bys =
             unsafe { slice::from_raw_parts((*self.0).aOrderBy, (*self.0).nOrderBy as usize) };
@@ -346,6 +350,7 @@ impl IndexInfo {
 
     /// Number of terms in the ORDER BY clause
     #[inline]
+    #[must_use]
     pub fn num_of_order_by(&self) -> usize {
         unsafe { (*self.0).nOrderBy as usize }
     }
@@ -448,18 +453,21 @@ pub struct IndexConstraint<'a>(&'a ffi::sqlite3_index_constraint);
 impl IndexConstraint<'_> {
     /// Column constrained.  -1 for ROWID
     #[inline]
+    #[must_use]
     pub fn column(&self) -> c_int {
         self.0.iColumn
     }
 
     /// Constraint operator
     #[inline]
+    #[must_use]
     pub fn operator(&self) -> IndexConstraintOp {
         IndexConstraintOp::from(self.0.op)
     }
 
     /// True if this constraint is usable
     #[inline]
+    #[must_use]
     pub fn is_usable(&self) -> bool {
         self.0.usable != 0
     }
@@ -509,12 +517,14 @@ pub struct OrderBy<'a>(&'a ffi::sqlite3_index_info_sqlite3_index_orderby);
 impl OrderBy<'_> {
     /// Column number
     #[inline]
+    #[must_use]
     pub fn column(&self) -> c_int {
         self.0.iColumn
     }
 
     /// True for DESC.  False for ASC.
     #[inline]
+    #[must_use]
     pub fn is_order_by_desc(&self) -> bool {
         self.0.desc != 0
     }
@@ -581,12 +591,14 @@ pub struct Values<'a> {
 impl Values<'_> {
     /// Returns the number of values.
     #[inline]
+    #[must_use]
     pub fn len(&self) -> usize {
         self.args.len()
     }
 
     /// Returns `true` if there is no value.
     #[inline]
+    #[must_use]
     pub fn is_empty(&self) -> bool {
         self.args.is_empty()
     }
@@ -629,6 +641,7 @@ impl Values<'_> {
 
     /// Turns `Values` into an iterator.
     #[inline]
+    #[must_use]
     pub fn iter(&self) -> ValueIter<'_> {
         ValueIter {
             iter: self.args.iter(),
@@ -720,6 +733,7 @@ impl InnerConnection {
 
 /// Escape double-quote (`"`) character occurrences by
 /// doubling them (`""`).
+#[must_use]
 pub fn escape_double_quote(identifier: &str) -> Cow<'_, str> {
     if identifier.contains('"') {
         // escape quote by doubling them
@@ -729,6 +743,7 @@ pub fn escape_double_quote(identifier: &str) -> Cow<'_, str> {
     }
 }
 /// Dequote string
+#[must_use]
 pub fn dequote(s: &str) -> &str {
     if s.len() < 2 {
         return s;
@@ -746,6 +761,7 @@ pub fn dequote(s: &str) -> &str {
 /// 1 yes true on
 /// 0 no false off
 /// ```
+#[must_use]
 pub fn parse_boolean(s: &str) -> Option<bool> {
     if s.eq_ignore_ascii_case("yes")
         || s.eq_ignore_ascii_case("on")