Try to catch clippy::pedantic violations in generated code

.github/workflows/ci.yml

@@ -39,4 +39,4 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: dtolnay/rust-toolchain@clippy
-      - run: cargo clippy -- -Dclippy::all
+      - run: cargo clippy --tests -- -Dclippy::all

impl/src/expand.rs

@@ -114,6 +114,7 @@ fn impl_struct(input: Struct) -> TokenStream {
     let display_impl = display_body.map(|body| {
         quote! {
             impl #impl_generics std::fmt::Display for #ty #ty_generics #where_clause {
+                #[allow(clippy::used_underscore_binding)]
                 fn fmt(&self, __formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
                     #body
                 }
@@ -296,7 +297,7 @@ fn impl_enum(input: Enum) -> TokenStream {
             impl #impl_generics std::fmt::Display for #ty #ty_generics #where_clause {
                 fn fmt(&self, __formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
                     #use_as_display
-                    #[allow(unused_variables, deprecated)]
+                    #[allow(unused_variables, deprecated, clippy::used_underscore_binding)]
                     match #void_deref self {
                         #(#arms,)*
                     }

tests/compiletest.rs

@@ -1,3 +1,5 @@
+#![deny(clippy::all, clippy::pedantic)]
+
 #[rustversion::attr(not(nightly), ignore)]
 #[test]
 fn ui() {

tests/test_deprecated.rs

@@ -1,4 +1,4 @@
-#![deny(deprecated)]
+#![deny(deprecated, clippy::all, clippy::pedantic)]
 
 use thiserror::Error;
 

tests/test_display.rs

@@ -1,3 +1,5 @@
+#![deny(clippy::all, clippy::pedantic)]
+
 use std::fmt::Display;
 use thiserror::Error;
 
@@ -114,6 +116,7 @@ fn test_nested() {
     #[error("!bool = {}", not(.0))]
     struct Error(bool);
 
+    #[allow(clippy::trivially_copy_pass_by_ref)]
     fn not(bool: &bool) -> bool {
         !*bool
     }
@@ -126,7 +129,7 @@ fn test_match() {
     #[derive(Error, Debug)]
     #[error("{}: {0}", match .1 {
         Some(n) => format!("error occurred with {}", n),
-        None => format!("there was an empty error"),
+        None => "there was an empty error".to_owned(),
     })]
     struct Error(String, Option<usize>);
 
@@ -142,6 +145,7 @@ fn test_match() {
 
 #[test]
 fn test_void() {
+    #[allow(clippy::empty_enum)]
     #[derive(Error, Debug)]
     #[error("...")]
     pub enum Error {}

tests/test_error.rs

@@ -1,3 +1,4 @@
+#![deny(clippy::all, clippy::pedantic)]
 #![allow(dead_code)]
 
 use std::fmt::{self, Display};

tests/test_expr.rs

@@ -1,3 +1,5 @@
+#![deny(clippy::all, clippy::pedantic)]
+
 use std::fmt::Display;
 use thiserror::Error;
 
@@ -39,8 +41,7 @@ pub enum RustupError {
         "toolchain '{name}' does not contain component {component}{}",
         .suggestion
             .as_ref()
-            .map(|s| format!("; did you mean '{}'?", s))
-            .unwrap_or_else(String::new),
+            .map_or_else(String::new, |s| format!("; did you mean '{}'?", s)),
     )]
     UnknownComponent {
         name: String,

tests/test_from.rs

@@ -1,3 +1,5 @@
+#![deny(clippy::all, clippy::pedantic)]
+
 use std::io;
 use thiserror::Error;
 

tests/test_option.rs

@@ -1,4 +1,5 @@
 #![cfg_attr(thiserror_nightly_testing, feature(backtrace))]
+#![deny(clippy::all, clippy::pedantic)]
 
 #[cfg(thiserror_nightly_testing)]
 pub mod structs {

tests/test_path.rs

@@ -1,3 +1,5 @@
+#![deny(clippy::all, clippy::pedantic)]
+
 use ref_cast::RefCast;
 use std::fmt::Display;
 use std::path::{Path, PathBuf};

tests/test_source.rs

@@ -1,3 +1,5 @@
+#![deny(clippy::all, clippy::pedantic)]
+
 use std::error::Error as StdError;
 use std::io;
 use thiserror::Error;

tests/test_transparent.rs

@@ -1,3 +1,5 @@
+#![deny(clippy::all, clippy::pedantic)]
+
 use anyhow::anyhow;
 use std::error::Error as _;
 use std::io;