Rollup merge of #96372 - compiler-errors:field-method-suggest, r=oli-obk

Suggest calling method on nested field when struct is missing method

Similar to the suggestion to change `x.field` to `x.nested.field`, implement a similar suggestion for when `x.method()` should be replaced with `x.nested.method()`.

4 files changed, 56 insertions, 0 deletions

diff --git a/src/test/ui/hrtb/issue-30786.migrate.stderr b/src/test/ui/hrtb/issue-30786.migrate.stderr
index 7ffe2f4cd7e..7157b186fc8 100644
--- a/src/test/ui/hrtb/issue-30786.migrate.stderr
+++ b/src/test/ui/hrtb/issue-30786.migrate.stderr
@@ -18,6 +18,10 @@ note: the following trait bounds were not satisfied:
    |
 LL | impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
    |         ---------     -                          ^^^^^^ unsatisfied trait bound introduced here
+help: one of the expressions' fields has a method of the same name
+   |
+LL |     let filter = map.stream.filterx(|x: &_| true);
+   |                      +++++++
 
 error[E0599]: the method `countx` exists for struct `Filter<Map<Repeat, for<'r> fn(&'r u64) -> &'r u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:139:30: 139:42]>`, but its trait bounds were not satisfied
   --> $DIR/issue-30786.rs:140:24
@@ -39,6 +43,10 @@ note: the following trait bounds were not satisfied:
    |
 LL | impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
    |         ---------     -                          ^^^^^^ unsatisfied trait bound introduced here
+help: one of the expressions' fields has a method of the same name
+   |
+LL |     let count = filter.stream.countx();
+   |                        +++++++
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/hrtb/issue-30786.nll.stderr b/src/test/ui/hrtb/issue-30786.nll.stderr
index 7ffe2f4cd7e..7157b186fc8 100644
--- a/src/test/ui/hrtb/issue-30786.nll.stderr
+++ b/src/test/ui/hrtb/issue-30786.nll.stderr
@@ -18,6 +18,10 @@ note: the following trait bounds were not satisfied:
    |
 LL | impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
    |         ---------     -                          ^^^^^^ unsatisfied trait bound introduced here
+help: one of the expressions' fields has a method of the same name
+   |
+LL |     let filter = map.stream.filterx(|x: &_| true);
+   |                      +++++++
 
 error[E0599]: the method `countx` exists for struct `Filter<Map<Repeat, for<'r> fn(&'r u64) -> &'r u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:139:30: 139:42]>`, but its trait bounds were not satisfied
   --> $DIR/issue-30786.rs:140:24
@@ -39,6 +43,10 @@ note: the following trait bounds were not satisfied:
    |
 LL | impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
    |         ---------     -                          ^^^^^^ unsatisfied trait bound introduced here
+help: one of the expressions' fields has a method of the same name
+   |
+LL |     let count = filter.stream.countx();
+   |                        +++++++
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/suggestions/field-has-method.rs b/src/test/ui/suggestions/field-has-method.rs
new file mode 100644
index 00000000000..980000151e2
--- /dev/null
+++ b/src/test/ui/suggestions/field-has-method.rs
@@ -0,0 +1,23 @@
+struct Kind;
+
+struct Ty {
+    kind: Kind,
+}
+
+impl Ty {
+    fn kind(&self) -> Kind {
+        todo!()
+    }
+}
+
+struct InferOk<T> {
+    value: T,
+    predicates: Vec<()>,
+}
+
+fn foo(i: InferOk<Ty>) {
+    let k = i.kind();
+    //~^ no method named `kind` found for struct `InferOk` in the current scope
+}
+
+fn main() {}
diff --git a/src/test/ui/suggestions/field-has-method.stderr b/src/test/ui/suggestions/field-has-method.stderr
new file mode 100644
index 00000000000..3a57436f200
--- /dev/null
+++ b/src/test/ui/suggestions/field-has-method.stderr
@@ -0,0 +1,17 @@
+error[E0599]: no method named `kind` found for struct `InferOk` in the current scope
+  --> $DIR/field-has-method.rs:19:15
+   |
+LL | struct InferOk<T> {
+   | ----------------- method `kind` not found for this
+...
+LL |     let k = i.kind();
+   |               ^^^^ method not found in `InferOk<Ty>`
+   |
+help: one of the expressions' fields has a method of the same name
+   |
+LL |     let k = i.value.kind();
+   |               ++++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0599`.