Replace displaydoc with a handrolled Display impl

Cargo.toml

@@ -11,8 +11,7 @@ documentation = "https://docs.rs/serde_php"
 
 [dependencies]
 serde = { version = "1" }
-smallvec = "0.6.10"
-displaydoc = "0.1.4"
+smallvec = "1.6"
 
 [dev-dependencies]
 serde_bytes = "0.11.2"

src/error.rs

@@ -1,48 +1,46 @@
 //! Top-level error type for PHP serialization/deserialization.
 
-use displaydoc::Display;
 use std::{fmt, io};
 
 /// Result type for PHP serialization/deserialization.
 pub type Result<T> = ::core::result::Result<T, Error>;
 
 /// PHP serialization/deserialization error.
-#[derive(Debug, Display)]
+#[derive(Debug)]
 pub enum Error {
-    /// Error writing serializated value: {0}
+    /// Error writing serialized value.
     WriteSerialized(io::Error),
-    /// Error reading serializing value: {0}
+    /// Error reading serializing value.
     ReadSerialized(io::Error),
-    /// Unexpected end of file while reading,
+    /// Unexpected end of file while reading.
     UnexpectedEof,
-    /// Expected `{expected}` but got `{actual}` instead.
+    /// Unexpected input.
     Unexpected {
         /// Byte expected.
         expected: char,
         /// Actual byte found.
         actual: char,
     },
-    /// Expected a digit, but got `{actual}` instead.
+    /// Expected a digit, but got non-digit value instead.
     ExpectedDigit {
         /// Non-digit found.
         actual: char,
     },
-    /// Deserialized bytestring is not valid UTF: {0}
+    /// Deserialized bytestring is not valid UTF.
     Utf8Error(std::str::Utf8Error),
-    /// Could not convert into char from decimal value: {0}
+    /// Could not convert into char from decimal value.
     CharConversionFailed(std::char::CharTryFromError),
-    /// Not a valid number or incorrect number type: {0}
+    /// Not a valid number or incorrect number type.
     NotAValidNumber(Box<dyn std::error::Error + Send + Sync>),
-    /// Not a valid value for boolean: {0}
+    /// Not a valid value for boolean.
     InvalidBooleanValue(char),
-    /// Unsupported array key type (must be all strings or all numeric): {0}
+    /// Unsupported array key type: must be all strings or all numeric.
     UnsupportedArrayKeyType(char),
-    /// Invalid type indicator on value: {0}
+    /// Invalid type indicator on value.
     InvalidTypeIndicator(char),
-    /// Feature not implemented by `serde_php`: {0}
+    /// Feature not implemented by `serde_php`.
     MissingFeature(&'static str),
-    /// Array-index mismatch (must be in-order and numeric), expected {expected}
-    /// but got {actual}
+    /// Array-index mismatch: must be in-order and numeric.
     IndexMismatch {
         /// Expected index.
         expected: usize,
@@ -55,9 +53,9 @@ pub enum Error {
     /// sequences of unknown length requires writing these to a memory buffer
     /// with potentially unbounded space requirements and is thus disabled.
     LengthRequired,
-    /// PHP Deserialization failed: {0}
+    /// PHP Deserialization failed.
     SerializationFailed(String),
-    /// PHP Serialization failed: {0}
+    /// PHP Serialization failed.
     DeserializationFailed(String),
 }
 
@@ -76,6 +74,42 @@ impl std::error::Error for Error {
     }
 }
 
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        #[allow(clippy::enum_glob_use)]
+        use Error::*;
+
+        match self {
+            WriteSerialized(err) => write!(f, "Error writing serialized value: {}", err),
+            ReadSerialized(err) => write!(f, "Error reading serializing value: {}", err),
+            UnexpectedEof => write!(f, "Unexpected end of file while reading"),
+            Unexpected { expected, actual } => {
+                write!(f, "Expected `{}` but got `{}` instead", expected, actual)
+            }
+            ExpectedDigit { actual } => write!(f, "Expected a digit, but got `{}` instead", actual),
+            Utf8Error(err) => write!(f, "Deserialized bytestring is not valid UTF: {}", err),
+            CharConversionFailed(err) => {
+                write!(f, "Could not convert into char from decimal value: {}", err)
+            }
+            NotAValidNumber(err) => {
+                write!(f, "Not a valid number or incorrect number type: {}", err)
+            }
+            InvalidBooleanValue(ch) => write!(f, "Not a valid value for boolean: {}", ch),
+            UnsupportedArrayKeyType(ch) => write!(f, "Unsupported array key type: {}", ch),
+            InvalidTypeIndicator(ch) => write!(f, "Invalid type indicator on value: {}", ch),
+            MissingFeature(feat) => write!(f, "Feature not implemented by `serde_php`: {}", feat),
+            IndexMismatch { expected, actual } => write!(
+                f,
+                "Array-index mismatch, expected {} but got {}",
+                expected, actual
+            ),
+            LengthRequired => write!(f, "Attempted to serialize sequence of unknown length"),
+            SerializationFailed(err) => write!(f, "PHP Deserialization failed: {}", err),
+            DeserializationFailed(err) => write!(f, "PHP Serialization failed: {}", err),
+        }
+    }
+}
+
 impl serde::ser::Error for Error {
     #[inline]
     fn custom<T>(msg: T) -> Self