add suggestion for expect

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -2342,6 +2342,17 @@ fn has_error_or_infer<'tcx>(tys: impl IntoIterator<Item = Ty<'tcx>>) -> bool {
                         provided_span,
                         format!("unexpected argument{idx}{provided_ty_name}"),
                     ));
+                    if self.provided_arg_tys.len() == 1
+                        && let Some(span) = self.maybe_suggest_expect_for_unwrap(provided_ty)
+                    {
+                        err.span_suggestion_verbose(
+                            span,
+                            "did you mean to use `expect`?",
+                            "expect",
+                            Applicability::MaybeIncorrect,
+                        );
+                        continue;
+                    }
                     let mut span = provided_span;
                     if span.can_be_used_for_suggestions()
                         && self.call_metadata.error_span.can_be_used_for_suggestions()
@@ -2772,6 +2783,22 @@ fn suggestion_code(&self) -> (Span, String) {
 
         (suggestion_span, suggestion)
     }
+
+    fn maybe_suggest_expect_for_unwrap(&self, provided_ty: Ty<'tcx>) -> Option<Span> {
+        let tcx = self.tcx();
+        if let Some(call_ident) = self.call_metadata.call_ident
+            && call_ident.name == sym::unwrap
+            && let Some(callee_ty) = self.callee_ty
+            && let ty::Adt(adt, _) = callee_ty.peel_refs().kind()
+            && (tcx.is_diagnostic_item(sym::Option, adt.did())
+                || tcx.is_diagnostic_item(sym::Result, adt.did()))
+            && self.may_coerce(provided_ty, Ty::new_static_str(tcx))
+        {
+            Some(call_ident.span)
+        } else {
+            None
+        }
+    }
 }
 
 struct ArgMatchingCtxt<'a, 'b, 'tcx> {

tests/ui/did_you_mean/expect-instead-of-unwrap.rs

@@ -0,0 +1,6 @@
+fn main() {
+    Ok(42).unwrap("wow");
+    //~^ ERROR this method takes 0 arguments but 1 argument was supplied
+    Some(42).unwrap("wow");
+    //~^ ERROR this method takes 0 arguments but 1 argument was supplied
+}

tests/ui/did_you_mean/expect-instead-of-unwrap.stderr

@@ -0,0 +1,31 @@
+error[E0061]: this method takes 0 arguments but 1 argument was supplied
+  --> $DIR/expect-instead-of-unwrap.rs:2:12
+   |
+LL |     Ok(42).unwrap("wow");
+   |            ^^^^^^ ----- unexpected argument of type `&'static str`
+   |
+note: method defined here
+  --> $SRC_DIR/core/src/result.rs:LL:COL
+help: did you mean to use `expect`?
+   |
+LL -     Ok(42).unwrap("wow");
+LL +     Ok(42).expect("wow");
+   |
+
+error[E0061]: this method takes 0 arguments but 1 argument was supplied
+  --> $DIR/expect-instead-of-unwrap.rs:4:14
+   |
+LL |     Some(42).unwrap("wow");
+   |              ^^^^^^ ----- unexpected argument of type `&'static str`
+   |
+note: method defined here
+  --> $SRC_DIR/core/src/option.rs:LL:COL
+help: did you mean to use `expect`?
+   |
+LL -     Some(42).unwrap("wow");
+LL +     Some(42).expect("wow");
+   |
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0061`.