Auto merge of rust-lang#17865 - ShoyuVanilla:exhaust-block, r=Veykril

fix: Missing non-exhaustive let diagnostics inside async or unsafe block

The reason that this test doesn't have a pointer deref case is because the following code;
```rust
fn test(ptr: *const Result<i32, !>) {
    unsafe {
        let Ok(_x) = *ptr;
    }
}
```
is getting a block with no stmts but tail one in here(thus, no diagnostic error),
https://github.com/rust-lang/rust-analyzer/blob/0daeb5c0b05cfdf2101b0f078c27539099bf38e6/crates/hir-ty/src/diagnostics/expr.rs#L256-L257
while the following is getting a block with a single stmt without tail 🤔
```rust
fn test(x: Result<i32, &'static !>) {
    let Ok(_y) = x;
}
```
I'll make a more deep inspection and file this as a new issue

_Originally posted by `@ShoyuVanilla` in rust-lang/rust-analyzer#17853 (comment)

Author: bors

src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/expr.rs

@@ -117,7 +117,7 @@ impl ExprValidator {
                 Expr::If { .. } => {
                     self.check_for_unnecessary_else(id, expr, db);
                 }
-                Expr::Block { .. } => {
+                Expr::Block { .. } | Expr::Async { .. } | Expr::Unsafe { .. } => {
                     self.validate_block(db, expr);
                 }
                 _ => {}
@@ -254,7 +254,12 @@ impl ExprValidator {
     }
 
     fn validate_block(&mut self, db: &dyn HirDatabase, expr: &Expr) {
-        let Expr::Block { statements, .. } = expr else { return };
+        let (Expr::Block { statements, .. }
+        | Expr::Async { statements, .. }
+        | Expr::Unsafe { statements, .. }) = expr
+        else {
+            return;
+        };
         let pattern_arena = Arena::new();
         let cx = MatchCheckCtx::new(self.owner.module(db.upcast()), self.owner, db);
         for stmt in &**statements {

src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/non_exhaustive_let.rs

@@ -41,6 +41,45 @@ fn main() {
 fn main() {
     let Some(_) | None = Some(5);
 }
+"#,
+        );
+    }
+
+    #[test]
+    fn option_nonexhaustive_inside_blocks() {
+        check_diagnostics(
+            r#"
+//- minicore: option
+fn main() {
+    '_a: {
+        let None = Some(5);
+          //^^^^ error: non-exhaustive pattern: `Some(_)` not covered
+    }
+}
+"#,
+        );
+
+        check_diagnostics(
+            r#"
+//- minicore: future, option
+fn main() {
+    let _ = async {
+        let None = Some(5);
+          //^^^^ error: non-exhaustive pattern: `Some(_)` not covered
+    };
+}
+"#,
+        );
+
+        check_diagnostics(
+            r#"
+//- minicore: option
+fn main() {
+    unsafe {
+        let None = Some(5);
+          //^^^^ error: non-exhaustive pattern: `Some(_)` not covered
+    }
+}
 "#,
         );
     }