fix: zero-length span with trailing semi-colon in block

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -3162,7 +3162,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         };
         if self.can_eq(self.param_env, expected_ty, ty) {
             err.span_suggestion_short(
-                stmt.span.with_lo(tail_expr.span.hi()),
+                stmt.span
+                    .with_lo(tail_expr.span.hi())
+                    .with_hi(tail_expr.span.hi() + rustc_span::BytePos(1)),
                 "remove this semicolon",
                 "",
                 Applicability::MachineApplicable,

tests/ui/typeck/issue-114251.rs

@@ -0,0 +1,11 @@
+// compile-flags: -C debug-assertions
+
+fn main() {
+    let kitty = {
+        assert!(());
+        //~^ ERROR: cannot apply unary operator `!` to type `()`
+    };
+
+    let cat: u8 = kitty;
+    //~^ ERROR: mismatched types
+}

tests/ui/typeck/issue-114251.stderr

@@ -0,0 +1,23 @@
+error[E0600]: cannot apply unary operator `!` to type `()`
+  --> $DIR/issue-114251.rs:6:9
+   |
+LL |         assert!(());
+   |         ^^^^^^^^^^^ cannot apply unary operator `!`
+   |
+   = note: this error originates in the macro `assert` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0308]: mismatched types
+  --> $DIR/issue-114251.rs:10:19
+   |
+LL |         assert!(());
+   |                    - help: remove this semicolon
+...
+LL |     let cat: u8 = kitty;
+   |              --   ^^^^^ expected `u8`, found `()`
+   |              |
+   |              expected due to this
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0308, E0600.
+For more information about an error, try `rustc --explain E0308`.