Rollup merge of #94146 - est31:let_else, r=cjgillot

Adopt let else in more places

Continuation of #89933, #91018, #91481, #93046, #93590, #94011.

I have extended my clippy lint to also recognize tuple passing and match statements. The diff caused by fixing it is way above 1 thousand lines. Thus, I split it up into multiple pull requests to make reviewing easier. This is the biggest of these PRs and handles the changes outside of rustdoc, rustc_typeck, rustc_const_eval, rustc_trait_selection, which were handled in PRs #94139, #94142, #94143, #94144.

2 files changed, 6 insertions, 9 deletions

diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs
index eb7c75cac05..20caed1b230 100644
--- a/compiler/rustc_ast_passes/src/ast_validation.rs
+++ b/compiler/rustc_ast_passes/src/ast_validation.rs
@@ -482,9 +482,8 @@ impl<'a> AstValidator<'a> {
     }
 
     fn check_foreign_kind_bodyless(&self, ident: Ident, kind: &str, body: Option<Span>) {
-        let body = match body {
-            None => return,
-            Some(body) => body,
+        let Some(body) = body else {
+            return;
         };
         self.err_handler()
             .struct_span_err(ident.span, &format!("incorrect `{}` inside `extern` block", kind))
@@ -504,9 +503,8 @@ impl<'a> AstValidator<'a> {
 
     /// An `fn` in `extern { ... }` cannot have a body `{ ... }`.
     fn check_foreign_fn_bodyless(&self, ident: Ident, body: Option<&Block>) {
-        let body = match body {
-            None => return,
-            Some(body) => body,
+        let Some(body) = body else {
+            return;
         };
         self.err_handler()
             .struct_span_err(ident.span, "incorrect function inside `extern` block")
diff --git a/compiler/rustc_ast_passes/src/show_span.rs b/compiler/rustc_ast_passes/src/show_span.rs
index 6cef26a13e6..27637e311f4 100644
--- a/compiler/rustc_ast_passes/src/show_span.rs
+++ b/compiler/rustc_ast_passes/src/show_span.rs
@@ -57,9 +57,8 @@ impl<'a> Visitor<'a> for ShowSpanVisitor<'a> {
 }
 
 pub fn run(span_diagnostic: &rustc_errors::Handler, mode: &str, krate: &ast::Crate) {
-    let mode = match mode.parse().ok() {
-        Some(mode) => mode,
-        None => return,
+    let Ok(mode) = mode.parse() else {
+        return;
     };
     let mut v = ShowSpanVisitor { span_diagnostic, mode };
     visit::walk_crate(&mut v, krate);