diff --git a/compiler/rustc_hir_typeck/src/demand.rs b/compiler/rustc_hir_typeck/src/demand.rs
index 7ba57b3b7a266..0ec10dc9ea32d 100644
--- a/compiler/rustc_hir_typeck/src/demand.rs
+++ b/compiler/rustc_hir_typeck/src/demand.rs
@@ -83,7 +83,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
self.annotate_expected_due_to_let_ty(err, expr, error);
self.emit_type_mismatch_suggestions(err, expr, expr_ty, expected, expected_ty_expr, error);
self.note_type_is_not_clone(err, expected, expr_ty, expr);
- self.note_internal_mutation_in_method(err, expr, expected, expr_ty);
+ self.note_internal_mutation_in_method(err, expr, Some(expected), expr_ty);
self.check_for_range_as_method_call(err, expr, expr_ty, expected);
self.check_for_binding_assigned_block_without_tail_expression(err, expr, expr_ty, expected);
self.check_wrong_return_type_due_to_generic_arg(err, expr, expr_ty);
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
index 2075537cad71f..578e5b0104657 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
@@ -955,44 +955,75 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
&self,
err: &mut Diagnostic,
expr: &hir::Expr<'_>,
- expected: Ty<'tcx>,
+ expected: Option<Ty<'tcx>>,
found: Ty<'tcx>,
) {
if found != self.tcx.types.unit {
return;
}
- if let ExprKind::MethodCall(path_segment, rcvr, ..) = expr.kind {
- if self
- .typeck_results
+
+ let ExprKind::MethodCall(path_segment, rcvr, ..) = expr.kind else {
+ return;
+ };
+
+ let rcvr_has_the_expected_type = self
+ .typeck_results
+ .borrow()
+ .expr_ty_adjusted_opt(rcvr)
+ .and_then(|ty| expected.map(|expected_ty| expected_ty.peel_refs() == ty.peel_refs()))
+ .unwrap_or(false);
+
+ let prev_call_mutates_and_returns_unit = || {
+ self.typeck_results
.borrow()
- .expr_ty_adjusted_opt(rcvr)
- .map_or(true, |ty| expected.peel_refs() != ty.peel_refs())
- {
- return;
- }
- let mut sp = MultiSpan::from_span(path_segment.ident.span);
- sp.push_span_label(
- path_segment.ident.span,
- format!(
- "this call modifies {} in-place",
- match rcvr.kind {
- ExprKind::Path(QPath::Resolved(
- None,
- hir::Path { segments: [segment], .. },
- )) => format!("`{}`", segment.ident),
- _ => "its receiver".to_string(),
- }
- ),
- );
+ .type_dependent_def_id(expr.hir_id)
+ .map(|def_id| self.tcx.fn_sig(def_id).skip_binder().skip_binder())
+ .and_then(|sig| sig.inputs_and_output.split_last())
+ .map(|(output, inputs)| {
+ output.is_unit()
+ && inputs
+ .get(0)
+ .and_then(|self_ty| self_ty.ref_mutability())
+ .map_or(false, rustc_ast::Mutability::is_mut)
+ })
+ .unwrap_or(false)
+ };
+
+ if !(rcvr_has_the_expected_type || prev_call_mutates_and_returns_unit()) {
+ return;
+ }
+
+ let mut sp = MultiSpan::from_span(path_segment.ident.span);
+ sp.push_span_label(
+ path_segment.ident.span,
+ format!(
+ "this call modifies {} in-place",
+ match rcvr.kind {
+ ExprKind::Path(QPath::Resolved(
+ None,
+ hir::Path { segments: [segment], .. },
+ )) => format!("`{}`", segment.ident),
+ _ => "its receiver".to_string(),
+ }
+ ),
+ );
+
+ let modifies_rcvr_note =
+ format!("method `{}` modifies its receiver in-place", path_segment.ident);
+ if rcvr_has_the_expected_type {
sp.push_span_label(
rcvr.span,
"you probably want to use this value after calling the method...",
);
+ err.span_note(sp, &modifies_rcvr_note);
+ err.note(&format!("...instead of the `()` output of method `{}`", path_segment.ident));
+ } else if let ExprKind::MethodCall(..) = rcvr.kind {
err.span_note(
sp,
- &format!("method `{}` modifies its receiver in-place", path_segment.ident),
+ modifies_rcvr_note.clone() + ", it is not meant to be used in method chains.",
);
- err.note(&format!("...instead of the `()` output of method `{}`", path_segment.ident));
+ } else {
+ err.span_note(sp, &modifies_rcvr_note);
}
}
diff --git a/compiler/rustc_hir_typeck/src/method/suggest.rs b/compiler/rustc_hir_typeck/src/method/suggest.rs
index 7055d9257ec90..50f2b71250c01 100644
--- a/compiler/rustc_hir_typeck/src/method/suggest.rs
+++ b/compiler/rustc_hir_typeck/src/method/suggest.rs
@@ -416,6 +416,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
);
probe.is_ok()
});
+
+ self.note_internal_mutation_in_method(
+ &mut err,
+ rcvr_expr,
+ expected.to_option(&self),
+ rcvr_ty,
+ );
}
let mut custom_span_label = false;
diff --git a/tests/ui/suggestions/chain-method-call-mutation-in-place.rs b/tests/ui/suggestions/chain-method-call-mutation-in-place.rs
index cb92ab87a8ff7..7a4c747961c62 100644
--- a/tests/ui/suggestions/chain-method-call-mutation-in-place.rs
+++ b/tests/ui/suggestions/chain-method-call-mutation-in-place.rs
@@ -1,4 +1,8 @@
-fn main() {}
+fn main() {
+ let x: Vec<i32> = vec![1, 2, 3].into_iter().collect::<Vec<i32>>().sort_by_key(|i| i); //~ ERROR mismatched types
+ vec![1, 2, 3].into_iter().collect::<Vec<i32>>().sort_by_key(|i| i).sort(); //~ ERROR no method named `sort` found for unit type `()` in the current scope
+}
+
fn foo(mut s: String) -> String {
s.push_str("asdf") //~ ERROR mismatched types
}
diff --git a/tests/ui/suggestions/chain-method-call-mutation-in-place.stderr b/tests/ui/suggestions/chain-method-call-mutation-in-place.stderr
index 11d9b8391f6d2..128160f10adb3 100644
--- a/tests/ui/suggestions/chain-method-call-mutation-in-place.stderr
+++ b/tests/ui/suggestions/chain-method-call-mutation-in-place.stderr
@@ -1,5 +1,33 @@
error[E0308]: mismatched types
- --> $DIR/chain-method-call-mutation-in-place.rs:3:5
+ --> $DIR/chain-method-call-mutation-in-place.rs:2:23
+ |
+LL | let x: Vec<i32> = vec![1, 2, 3].into_iter().collect::<Vec<i32>>().sort_by_key(|i| i);
+ | -------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `Vec<i32>`, found `()`
+ | |
+ | expected due to this
+ |
+ = note: expected struct `Vec<i32>`
+ found unit type `()`
+note: method `sort_by_key` modifies its receiver in-place, it is not meant to be used in method chains.
+ --> $DIR/chain-method-call-mutation-in-place.rs:2:71
+ |
+LL | let x: Vec<i32> = vec![1, 2, 3].into_iter().collect::<Vec<i32>>().sort_by_key(|i| i);
+ | ^^^^^^^^^^^ this call modifies its receiver in-place
+
+error[E0599]: no method named `sort` found for unit type `()` in the current scope
+ --> $DIR/chain-method-call-mutation-in-place.rs:3:72
+ |
+LL | vec![1, 2, 3].into_iter().collect::<Vec<i32>>().sort_by_key(|i| i).sort();
+ | ^^^^ method not found in `()`
+ |
+note: method `sort_by_key` modifies its receiver in-place, it is not meant to be used in method chains.
+ --> $DIR/chain-method-call-mutation-in-place.rs:3:53
+ |
+LL | vec![1, 2, 3].into_iter().collect::<Vec<i32>>().sort_by_key(|i| i).sort();
+ | ^^^^^^^^^^^ this call modifies its receiver in-place
+
+error[E0308]: mismatched types
+ --> $DIR/chain-method-call-mutation-in-place.rs:7:5
|
LL | fn foo(mut s: String) -> String {
| ------ expected `String` because of return type
@@ -7,7 +35,7 @@ LL | s.push_str("asdf")
| ^^^^^^^^^^^^^^^^^^ expected `String`, found `()`
|
note: method `push_str` modifies its receiver in-place
- --> $DIR/chain-method-call-mutation-in-place.rs:3:7
+ --> $DIR/chain-method-call-mutation-in-place.rs:7:7
|
LL | s.push_str("asdf")
| - ^^^^^^^^ this call modifies `s` in-place
@@ -15,6 +43,7 @@ LL | s.push_str("asdf")
| you probably want to use this value after calling the method...
= note: ...instead of the `()` output of method `push_str`
-error: aborting due to previous error
+error: aborting due to 3 previous errors
-For more information about this error, try `rustc --explain E0308`.
+Some errors have detailed explanations: E0308, E0599.
+For more information about an error, try `rustc --explain E0308`.