Merge rust-bitcoin/rust-bitcoin#6894: Harden `Copy` policy and apply to all pre-1.0 crates

### chacha20_poly1305/src/lib.rs
@@ -169,7 +169,7 @@ pub mod error {
     use core::fmt;
 
     /// Errors encrypting and decrypting messages with `ChaCha20` and `Poly1305` authentication tags.
-    #[derive(Copy, Clone, Debug, PartialEq, Eq)]
+    #[derive(Clone, Debug, PartialEq, Eq)]
     pub enum Error {
         /// Additional data showing up when it is not expected.
         UnauthenticatedAdditionalData,

### docs/policy.md
@@ -204,7 +204,7 @@ More specifically an error should
 
 - be `non_exhaustive` unless we _really_ never want to change it.
 - have private fields unless we are very confident they won't change.
-- derive `Debug, Clone, PartialEq, Eq` (and `Copy` if and only if not `non_exhaustive`).
+- derive `Debug, Clone, PartialEq, Eq`. Do not derive `Copy` unless you have to.
 - implement Display using `write_err!()` macro if a variant contains an inner error source.
 - have `Error` suffix on error types (structs and enums).
 - not have `Error` suffix on enum variants.

### key_expression/src/bip32.rs
@@ -1362,7 +1362,7 @@ pub mod error {
     /// Attempted to derive a child of depth 256 or higher.
     ///
     /// There is no way to encode such xkeys.
-    #[derive(Debug, Copy, Clone, PartialEq, Eq)]
+    #[derive(Debug, Clone, PartialEq, Eq)]
     #[non_exhaustive]
     pub struct MaximumDepthExceededError {}
 
@@ -1382,7 +1382,7 @@ pub mod error {
     /// Attempted to derive a hardened child from an xpub.
     ///
     /// You can only derive hardened children from xprivs.
-    #[derive(Debug, Copy, Clone, PartialEq, Eq)]
+    #[derive(Debug, Clone, PartialEq, Eq)]
     #[non_exhaustive]
     pub struct CannotDeriveHardenedChildError {}
 
@@ -1400,7 +1400,7 @@ pub mod error {
     }
 
     /// Error deriving an extended public key.
-    #[derive(Debug, Copy, Clone, PartialEq, Eq)]
+    #[derive(Debug, Clone, PartialEq, Eq)]
     #[non_exhaustive]
     pub enum DeriveXpubError {
         /// Attempted to derive a hardened child from an xpub.
@@ -1602,7 +1602,7 @@ pub mod error {
     }
 
     /// Master seed had an invalid length.
-    #[derive(Debug, Copy, Clone, PartialEq, Eq)]
+    #[derive(Debug, Clone, PartialEq, Eq)]
     pub struct InvalidSeedLengthError {
         pub(crate) length: usize,
     }

### p2p/src/address.rs
@@ -776,7 +776,7 @@ pub mod error {
     ///
     /// Addresses like Tor, I2P, and CJDNS use different routing mechanisms
     /// and cannot be represented as standard IP addresses or socket addresses.
-    #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+    #[derive(Debug, Clone, PartialEq, Eq, Hash)]
     #[non_exhaustive]
     pub enum UnroutableAddressError {
         /// Tor V2 onion address.

### p2p/src/bip434.rs
@@ -236,7 +236,7 @@ pub mod error {
     use super::{Feature, FeatureData, FeatureId};
 
     /// Errors related to a [`FeatureId`].
-    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
+    #[derive(Debug, Clone, PartialEq, Eq)]
     pub enum FeatureIdError {
         /// Invalid length for [`FeatureId`].
         InvalidLength(usize),
@@ -270,7 +270,7 @@ pub mod error {
     }
 
     /// Errors related to a [`FeatureData`].
-    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
+    #[derive(Debug, Clone, PartialEq, Eq)]
     pub struct FeatureDataError {
         /// Data too long.
         pub too_long: usize,

### units/src/amount/error.rs
@@ -120,15 +120,15 @@ impl std::error::Error for ParseAmountError {
 }
 
 /// Error returned when a parsed amount is too big or too small.
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+#[derive(Debug, Clone, Eq, PartialEq)]
 pub struct OutOfRangeError {
     pub(super) is_signed: bool,
     pub(super) is_greater_than_max: bool,
 }
 
 impl OutOfRangeError {
     /// Returns the minimum value of the type that was attempted to be parsed.
-    fn lower_bound(self) -> SignedAmount {
+    fn lower_bound(&self) -> SignedAmount {
         if self.is_signed() {
             SignedAmount::MIN
         } else {
@@ -139,15 +139,15 @@ impl OutOfRangeError {
     /// Returns true if the type that was attempted to be parsed is signed (`SignedAmount`).
     ///
     /// This can be used to hint to users to enter non-negative values specifically.
-    pub fn is_signed(self) -> bool { self.is_signed }
+    pub fn is_signed(&self) -> bool { self.is_signed }
 
     /// Returns true if the input value was larger than the maximum allowed value.
     #[inline]
-    pub fn is_above_max(self) -> bool { self.is_greater_than_max }
+    pub fn is_above_max(&self) -> bool { self.is_greater_than_max }
 
     /// Returns true if the input value was smaller than the minimum allowed value.
     #[inline]
-    pub fn is_below_min(self) -> bool { !self.is_greater_than_max }
+    pub fn is_below_min(&self) -> bool { !self.is_greater_than_max }
 
     #[cfg(test)]
     #[inline]