Revert "Ignore using destructuring assignment to wildcard pattern"

This reverts commit 13cd0a2.

Author: dtolnay

benches/rust.rs

@@ -7,6 +7,7 @@
 #![recursion_limit = "1024"]
 #![allow(
     clippy::cast_lossless,
+    clippy::let_underscore_untyped,
     clippy::manual_let_else,
     clippy::match_like_matches_macro,
     clippy::uninlined_format_args,
@@ -98,7 +99,7 @@ mod librustc_parse {
 #[cfg(not(syn_only))]
 mod read_from_disk {
     pub fn bench(content: &str) -> Result<(), ()> {
-        _ = content;
+        let _ = content;
         Ok(())
     }
 }

examples/dump-syntax/src/main.rs

@@ -55,14 +55,14 @@ impl Display for Error {
 
 fn main() {
     if let Err(error) = try_main() {
-        _ = writeln!(io::stderr(), "{}", error);
+        let _ = writeln!(io::stderr(), "{}", error);
         process::exit(1);
     }
 }
 
 fn try_main() -> Result<(), Error> {
     let mut args = env::args_os();
-    _ = args.next(); // executable name
+    let _ = args.next(); // executable name
 
     let filepath = match (args.next(), args.next()) {
         (Some(arg), None) => PathBuf::from(arg),

fuzz/fuzz_targets/create_token_buffer.rs

@@ -12,7 +12,7 @@ fn immediate_fail(_input: ParseStream) -> syn::Result<()> {
 fuzz_target!(|data: &[u8]| {
     if data.len() < 300 {
         if let Ok(string) = str::from_utf8(data) {
-            _ = immediate_fail.parse_str(string);
+            let _ = immediate_fail.parse_str(string);
         }
     }
 });

fuzz/fuzz_targets/parse_file.rs

@@ -6,7 +6,7 @@ use std::str;
 fuzz_target!(|data: &[u8]| {
     if data.len() < 300 {
         if let Ok(string) = str::from_utf8(data) {
-            _ = syn::parse_file(string);
+            let _ = syn::parse_file(string);
         }
     }
 });

tests/crates/main.rs

@@ -10,7 +10,7 @@
 //        | jq '"https://static.crates.io/crates/" + .name + "/" + .name + "-" + .vers + ".crate"' -r \
 //        | xargs -P10 -n100 wget -nc
 
-#![allow(clippy::uninlined_format_args)]
+#![allow(clippy::let_underscore_untyped, clippy::uninlined_format_args)]
 
 use anyhow::{ensure, Result};
 use flate2::read::GzDecoder;
@@ -78,7 +78,7 @@ fn parse(path: &Path, oversize_count: &AtomicUsize) -> Result<()> {
         if entry.read_to_string(&mut contents).is_err() {
             break;
         }
-        _ = syn::parse_file(&contents);
+        let _ = syn::parse_file(&contents);
     }
     Ok(())
 }

tests/features/macro/lib.rs

@@ -1,4 +1,8 @@
-#![allow(clippy::toplevel_ref_arg, clippy::uninlined_format_args)]
+#![allow(
+    clippy::let_underscore_untyped,
+    clippy::toplevel_ref_arg,
+    clippy::uninlined_format_args
+)]
 
 use proc_macro::TokenStream;
 use std::io::Write;
@@ -23,31 +27,31 @@ pub fn check(_input: TokenStream) -> TokenStream {
 
     if cfg!(debug_assertions) {
         let yellow = ColorSpec::new().set_fg(Some(Color::Yellow)).clone();
-        _ = writeln!(stderr);
-        _ = stderr.set_color(yellow.clone().set_bold(true));
-        _ = write!(stderr, "NOTE");
+        let _ = writeln!(stderr);
+        let _ = stderr.set_color(yellow.clone().set_bold(true));
+        let _ = write!(stderr, "NOTE");
         for line in DEBUG_NOTE.lines() {
-            _ = stderr.set_color(&yellow);
-            _ = writeln!(stderr, "{}", line);
+            let _ = stderr.set_color(&yellow);
+            let _ = writeln!(stderr, "{}", line);
         }
-        _ = stderr.reset();
-        _ = writeln!(stderr);
+        let _ = stderr.reset();
+        let _ = writeln!(stderr);
         needs_newline = false;
     }
 
     if cfg!(not(feature = "all-features")) {
         let red = ColorSpec::new().set_fg(Some(Color::Red)).clone();
         if needs_newline {
-            _ = writeln!(stderr);
+            let _ = writeln!(stderr);
         }
-        _ = stderr.set_color(red.clone().set_bold(true));
-        _ = write!(stderr, "ERROR");
+        let _ = stderr.set_color(red.clone().set_bold(true));
+        let _ = write!(stderr, "ERROR");
         for line in FEATURES_ERROR.lines() {
-            _ = stderr.set_color(&red);
-            _ = writeln!(stderr, "{}", line);
+            let _ = stderr.set_color(&red);
+            let _ = writeln!(stderr, "{}", line);
         }
-        _ = stderr.reset();
-        _ = writeln!(stderr);
+        let _ = stderr.reset();
+        let _ = writeln!(stderr);
         process::exit(1);
     }
 

tests/regression.rs

@@ -1,4 +1,4 @@
-#![allow(clippy::uninlined_format_args)]
+#![allow(clippy::let_underscore_untyped, clippy::uninlined_format_args)]
 
 mod regression {
     automod::dir!("tests/regression");

tests/regression/issue1108.rs

@@ -1,5 +1,5 @@
 #[test]
 fn issue1108() {
     let data = "impl<x<>>::x for";
-    _ = syn::parse_file(data);
+    let _ = syn::parse_file(data);
 }

tests/test_parse_stream.rs

@@ -1,12 +1,14 @@
+#![allow(clippy::let_underscore_untyped)]
+
 use syn::ext::IdentExt;
 use syn::parse::ParseStream;
 use syn::{Ident, Token};
 
 #[test]
 fn test_peek() {
-    _ = |input: ParseStream| {
-        _ = input.peek(Ident);
-        _ = input.peek(Ident::peek_any);
-        _ = input.peek(Token![::]);
+    let _ = |input: ParseStream| {
+        let _ = input.peek(Ident);
+        let _ = input.peek(Ident::peek_any);
+        let _ = input.peek(Token![::]);
     };
 }

tests/test_precedence.rs

@@ -4,6 +4,7 @@
 #![feature(rustc_private)]
 #![allow(
     clippy::explicit_deref_methods,
+    clippy::let_underscore_untyped,
     clippy::manual_assert,
     clippy::manual_let_else,
     clippy::match_like_matches_macro,
@@ -317,15 +318,15 @@ fn librustc_brackets(mut librustc_expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
         // types yet. We'll look into comparing those in the future. For now
         // focus on expressions appearing in other places.
         fn visit_pat(&mut self, pat: &mut P<Pat>) {
-            _ = pat;
+            let _ = pat;
         }
 
         fn visit_ty(&mut self, ty: &mut P<Ty>) {
-            _ = ty;
+            let _ = ty;
         }
 
         fn visit_attribute(&mut self, attr: &mut Attribute) {
-            _ = attr;
+            let _ = attr;
         }
     }