Rollup merge of #100898 - compiler-errors:too-many-expr-fields, r=spastorino

Do not report too many expr field candidates

When considering "this expressions' field has a {field/method}" suggestions:
1. Don't report methods that are out of scope
2. Use `span_suggestions` instead of reporting each field candidate, which caps the number of suggestions to 4
4. Blacklist some common traits like `Clone` and `Deref`

Fixes #100894

5 files changed, 73 insertions, 16 deletions

diff --git a/src/test/ui/copy-a-resource.stderr b/src/test/ui/copy-a-resource.stderr
index b92449c6e0a..128087f1e37 100644
--- a/src/test/ui/copy-a-resource.stderr
+++ b/src/test/ui/copy-a-resource.stderr
@@ -10,10 +10,6 @@ LL |     let _y = x.clone();
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following trait defines an item `clone`, perhaps you need to implement it:
            candidate #1: `Clone`
-help: one of the expressions' fields has a method of the same name
-   |
-LL |     let _y = x.i.clone();
-   |                ++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-2823.stderr b/src/test/ui/issues/issue-2823.stderr
index 208b340d064..b5a2b2f55a6 100644
--- a/src/test/ui/issues/issue-2823.stderr
+++ b/src/test/ui/issues/issue-2823.stderr
@@ -10,10 +10,6 @@ LL |     let _d = c.clone();
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following trait defines an item `clone`, perhaps you need to implement it:
            candidate #1: `Clone`
-help: one of the expressions' fields has a method of the same name
-   |
-LL |     let _d = c.x.clone();
-   |                ++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/noncopyable-class.stderr b/src/test/ui/noncopyable-class.stderr
index 15e22e946da..0c696163a26 100644
--- a/src/test/ui/noncopyable-class.stderr
+++ b/src/test/ui/noncopyable-class.stderr
@@ -10,14 +10,6 @@ LL |     let _y = x.clone();
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following trait defines an item `clone`, perhaps you need to implement it:
            candidate #1: `Clone`
-help: one of the expressions' fields has a method of the same name
-   |
-LL |     let _y = x.i.clone();
-   |                ++
-help: one of the expressions' fields has a method of the same name
-   |
-LL |     let _y = x.j.x.clone();
-   |                ++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/suggestions/too-many-field-suggestions.rs b/src/test/ui/suggestions/too-many-field-suggestions.rs
new file mode 100644
index 00000000000..905f9502cf5
--- /dev/null
+++ b/src/test/ui/suggestions/too-many-field-suggestions.rs
@@ -0,0 +1,29 @@
+struct Thing {
+    a0: Foo,
+    a1: Foo,
+    a2: Foo,
+    a3: Foo,
+    a4: Foo,
+    a5: Foo,
+    a6: Foo,
+    a7: Foo,
+    a8: Foo,
+    a9: Foo,
+}
+
+struct Foo {
+    field: Field,
+}
+
+struct Field;
+
+impl Foo {
+    fn bar(&self) {}
+}
+
+fn bar(t: Thing) {
+    t.bar(); //~ ERROR no method named `bar` found for struct `Thing`
+    t.field; //~ ERROR no field `field` on type `Thing`
+}
+
+fn main() {}
diff --git a/src/test/ui/suggestions/too-many-field-suggestions.stderr b/src/test/ui/suggestions/too-many-field-suggestions.stderr
new file mode 100644
index 00000000000..63ad6fdb169
--- /dev/null
+++ b/src/test/ui/suggestions/too-many-field-suggestions.stderr
@@ -0,0 +1,44 @@
+error[E0599]: no method named `bar` found for struct `Thing` in the current scope
+  --> $DIR/too-many-field-suggestions.rs:25:7
+   |
+LL | struct Thing {
+   | ------------ method `bar` not found for this struct
+...
+LL |     t.bar();
+   |       ^^^ method not found in `Thing`
+   |
+help: some of the expressions' fields have a method of the same name
+   |
+LL |     t.a0.bar();
+   |       +++
+LL |     t.a1.bar();
+   |       +++
+LL |     t.a2.bar();
+   |       +++
+LL |     t.a3.bar();
+   |       +++
+     and 6 other candidates
+
+error[E0609]: no field `field` on type `Thing`
+  --> $DIR/too-many-field-suggestions.rs:26:7
+   |
+LL |     t.field;
+   |       ^^^^^ unknown field
+   |
+   = note: available fields are: `a0`, `a1`, `a2`, `a3`, `a4` ... and 5 others
+help: some of the expressions' fields have a field of the same name
+   |
+LL |     t.a0.field;
+   |       +++
+LL |     t.a1.field;
+   |       +++
+LL |     t.a2.field;
+   |       +++
+LL |     t.a3.field;
+   |       +++
+     and 6 other candidates
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0599, E0609.
+For more information about an error, try `rustc --explain E0599`.