From d35fc61d3fd94861debc69cf7ccce3d04c834893 Mon Sep 17 00:00:00 2001
From: Christopher Durham <cad97@cad97.com>
Date: Mon, 15 Aug 2022 18:42:20 -0500
Subject: [PATCH 1/3] Remove trait bound from Error type

---
 pest/src/error.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pest/src/error.rs b/pest/src/error.rs
index c2ab8066..c199ad98 100644
--- a/pest/src/error.rs
+++ b/pest/src/error.rs
@@ -26,7 +26,7 @@ use crate::RuleType;
 #[derive(Clone, Debug, Eq, Hash, PartialEq)]
 #[cfg_attr(feature = "std", derive(thiserror::Error))]
 #[cfg_attr(feature = "std", error("{}", self.format()))]
-pub struct Error<R: RuleType> {
+pub struct Error<R> {
     /// Variant of the error
     pub variant: ErrorVariant<R>,
     /// Location within the input string
@@ -41,7 +41,7 @@ pub struct Error<R: RuleType> {
 /// Different kinds of parsing errors.
 #[derive(Clone, Debug, Eq, Hash, PartialEq)]
 #[cfg_attr(feature = "std", derive(thiserror::Error))]
-pub enum ErrorVariant<R: RuleType> {
+pub enum ErrorVariant<R> {
     /// Generated parsing error with expected and unexpected `Rule`s
     #[cfg_attr(feature = "std", error("parsing error: {}", self.message()))]
     ParsingError {

From 8fbf5da1be8522c5fd8a21bb632da36d92cb5b1f Mon Sep 17 00:00:00 2001
From: Christopher Durham <cad97@cad97.com>
Date: Mon, 15 Aug 2022 20:05:54 -0500
Subject: [PATCH 2/3] Return manual Error Display impl

---
 pest/src/error.rs | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/pest/src/error.rs b/pest/src/error.rs
index c199ad98..cec778b1 100644
--- a/pest/src/error.rs
+++ b/pest/src/error.rs
@@ -16,6 +16,7 @@ use alloc::string::String;
 use alloc::string::ToString;
 use alloc::vec::Vec;
 use core::cmp;
+use core::fmt;
 use core::mem;
 
 use crate::position::Position;
@@ -25,7 +26,6 @@ use crate::RuleType;
 /// Parse-related error type.
 #[derive(Clone, Debug, Eq, Hash, PartialEq)]
 #[cfg_attr(feature = "std", derive(thiserror::Error))]
-#[cfg_attr(feature = "std", error("{}", self.format()))]
 pub struct Error<R> {
     /// Variant of the error
     pub variant: ErrorVariant<R>,
@@ -43,7 +43,6 @@ pub struct Error<R> {
 #[cfg_attr(feature = "std", derive(thiserror::Error))]
 pub enum ErrorVariant<R> {
     /// Generated parsing error with expected and unexpected `Rule`s
-    #[cfg_attr(feature = "std", error("parsing error: {}", self.message()))]
     ParsingError {
         /// Positive attempts
         positives: Vec<R>,
@@ -51,7 +50,6 @@ pub enum ErrorVariant<R> {
         negatives: Vec<R>,
     },
     /// Custom error with a message
-    #[cfg_attr(feature = "std", error("{}", self.message()))]
     CustomError {
         /// Short explanation
         message: String,
@@ -520,6 +518,18 @@ impl<R: RuleType> ErrorVariant<R> {
     }
 }
 
+impl<R: RuleType> fmt::Display for Error<R> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.format())
+    }
+}
+
+impl<R: RuleType> fmt::Display for ErrorVariant<R> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.message())
+    }
+}
+
 fn visualize_whitespace(input: &str) -> String {
     input.to_owned().replace('\r', "␍").replace('\n', "␊")
 }

From 5aa9ff20b65c5cb42de2e55df439f6a13afbd856 Mon Sep 17 00:00:00 2001
From: Christopher Durham <cad97@cad97.com>
Date: Mon, 15 Aug 2022 20:07:39 -0500
Subject: [PATCH 3/3] Restore `parsing error:` error introducer

---
 pest/src/error.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/pest/src/error.rs b/pest/src/error.rs
index cec778b1..a83e23a4 100644
--- a/pest/src/error.rs
+++ b/pest/src/error.rs
@@ -526,7 +526,10 @@ impl<R: RuleType> fmt::Display for Error<R> {
 
 impl<R: RuleType> fmt::Display for ErrorVariant<R> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "{}", self.message())
+        match self {
+            ErrorVariant::ParsingError { .. } => write!(f, "parsing error: {}", self.message()),
+            ErrorVariant::CustomError { .. } => write!(f, "{}", self.message()),
+        }
     }
 }