Rollup merge of rust-lang#84499 - estebank:issue-84272, r=jackh726

Dylan-DPC · web-flow · commit 5aca6daa37d4 · 2021-04-25T16:49:41.000+02:00
Tweak trait not `use`d suggestion Fix rust-lang#84272. Follow up to rust-lang#83667.
diff --git a/compiler/rustc_typeck/src/check/method/suggest.rs b/compiler/rustc_typeck/src/check/method/suggest.rs
@@ -988,6 +988,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let mut alt_rcvr_sugg = false;
         if let SelfSource::MethodCall(rcvr) = source {
             debug!(?span, ?item_name, ?rcvr_ty, ?rcvr);
+            let skippable = [
+                self.tcx.lang_items().clone_trait(),
+                self.tcx.lang_items().deref_trait(),
+                self.tcx.lang_items().deref_mut_trait(),
+                self.tcx.lang_items().drop_trait(),
+            ];
             // Try alternative arbitrary self types that could fulfill this call.
             // FIXME: probe for all types that *could* be arbitrary self-types, not
             // just this list.
@@ -996,6 +1002,27 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 (self.tcx.mk_mut_ref(&ty::ReErased, rcvr_ty), "&mut "),
                 (self.tcx.mk_imm_ref(&ty::ReErased, rcvr_ty), "&"),
             ] {
+                if let Ok(pick) = self.lookup_probe(
+                    span,
+                    item_name,
+                    rcvr_ty,
+                    rcvr,
+                    crate::check::method::probe::ProbeScope::AllTraits,
+                ) {
+                    // If the method is defined for the receiver we have, it likely wasn't `use`d.
+                    // We point at the method, but we just skip the rest of the check for arbitrary
+                    // self types and rely on the suggestion to `use` the trait from
+                    // `suggest_valid_traits`.
+                    let did = Some(pick.item.container.id());
+                    let skip = skippable.contains(&did);
+                    if pick.autoderefs == 0 && !skip {
+                        err.span_label(
+                            pick.item.ident.span,
+                            &format!("the method is available for `{}` here", rcvr_ty),
+                        );
+                    }
+                    break;
+                }
                 for (rcvr_ty, pre) in &[
                     (self.tcx.mk_lang_item(rcvr_ty, LangItem::OwnedBox), "Box::new"),
                     (self.tcx.mk_lang_item(rcvr_ty, LangItem::Pin), "Pin::new"),
@@ -1015,13 +1042,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             // We don't want to suggest a container type when the missing
                             // method is `.clone()` or `.deref()` otherwise we'd suggest
                             // `Arc::new(foo).clone()`, which is far from what the user wants.
-                            let skip = [
-                                self.tcx.lang_items().clone_trait(),
-                                self.tcx.lang_items().deref_trait(),
-                                self.tcx.lang_items().deref_mut_trait(),
-                                self.tcx.lang_items().drop_trait(),
-                            ]
-                            .contains(&did);
+                            let skip = skippable.contains(&did);
                             // Make sure the method is defined for the *actual* receiver: we don't
                             // want to treat `Box<Self>` as a receiver if it only works because of
                             // an autoderef to `&self`
@@ -1047,7 +1068,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }
             }
         }
-        if !alt_rcvr_sugg && self.suggest_valid_traits(err, valid_out_of_scope_traits) {
+        if self.suggest_valid_traits(err, valid_out_of_scope_traits) {
             return;
         }
 
diff --git a/src/test/ui/hygiene/trait_items.stderr b/src/test/ui/hygiene/trait_items.stderr
@@ -1,6 +1,9 @@
 error[E0599]: no method named `f` found for unit type `()` in the current scope
   --> $DIR/trait_items.rs:17:24
    |
+LL |         fn f(&self) {}
+   |            - the method is available for `()` here
+...
 LL |     fn f() { ::baz::m!(); }
    |              ------------ in this macro invocation
 ...
diff --git a/src/test/ui/impl-trait/no-method-suggested-traits.stderr b/src/test/ui/impl-trait/no-method-suggested-traits.stderr
@@ -37,6 +37,9 @@ LL | use no_method_suggested_traits::Reexported;
 error[E0599]: no method named `method` found for type `char` in the current scope
   --> $DIR/no-method-suggested-traits.rs:30:9
    |
+LL |         fn method(&self) {}
+   |            ------ the method is available for `char` here
+...
 LL |     'a'.method();
    |         ^^^^^^ method not found in `char`
    |
@@ -63,6 +66,11 @@ error[E0599]: no method named `method` found for type `i32` in the current scope
    |
 LL |     1i32.method();
    |          ^^^^^^ method not found in `i32`
+   | 
+  ::: $DIR/auxiliary/no_method_suggested_traits.rs:8:12
+   |
+LL |         fn method(&self) {}
+   |            ------ the method is available for `i32` here
    |
    = help: items from traits can only be used if the trait is in scope
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
diff --git a/src/test/ui/issues/issue-43189.stderr b/src/test/ui/issues/issue-43189.stderr
@@ -3,6 +3,11 @@ error[E0599]: no method named `a` found for unit type `()` in the current scope
    |
 LL |     ().a();
    |        ^ method not found in `()`
+   | 
+  ::: $DIR/auxiliary/xcrate-issue-43189-a.rs:5:8
+   |
+LL |     fn a(&self) {}
+   |        - the method is available for `()` here
    |
    = help: items from traits can only be used if the trait is in scope
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
diff --git a/src/test/ui/issues/issue-56175.stderr b/src/test/ui/issues/issue-56175.stderr
@@ -3,6 +3,11 @@ error[E0599]: no method named `trait_method` found for struct `FooStruct` in the
    |
 LL |     reexported_trait::FooStruct.trait_method();
    |                                 ^^^^^^^^^^^^ method not found in `FooStruct`
+   | 
+  ::: $DIR/auxiliary/reexported-trait.rs:3:12
+   |
+LL |         fn trait_method(&self) {
+   |            ------------ the method is available for `FooStruct` here
    |
    = help: items from traits can only be used if the trait is in scope
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
@@ -15,6 +20,11 @@ error[E0599]: no method named `trait_method_b` found for struct `FooStruct` in t
    |
 LL |     reexported_trait::FooStruct.trait_method_b();
    |                                 ^^^^^^^^^^^^^^ method not found in `FooStruct`
+   | 
+  ::: $DIR/auxiliary/reexported-trait.rs:7:12
+   |
+LL |         fn trait_method_b(&self) {
+   |            -------------- the method is available for `FooStruct` here
    |
    = help: items from traits can only be used if the trait is in scope
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
diff --git a/src/test/ui/rust-2018/trait-import-suggestions.stderr b/src/test/ui/rust-2018/trait-import-suggestions.stderr
@@ -1,6 +1,9 @@
 error[E0599]: no method named `foobar` found for type `u32` in the current scope
   --> $DIR/trait-import-suggestions.rs:22:11
    |
+LL |             fn foobar(&self) { }
+   |                ------ the method is available for `u32` here
+...
 LL |         x.foobar();
    |           ^^^^^^ method not found in `u32`
    |
@@ -11,6 +14,9 @@ LL |         x.foobar();
 error[E0599]: no method named `bar` found for type `u32` in the current scope
   --> $DIR/trait-import-suggestions.rs:28:7
    |
+LL |         fn bar(&self) { }
+   |            --- the method is available for `u32` here
+...
 LL |     x.bar();
    |       ^^^ method not found in `u32`
    |
diff --git a/src/test/ui/shadowed/shadowed-trait-methods.stderr b/src/test/ui/shadowed/shadowed-trait-methods.stderr
@@ -1,6 +1,9 @@
 error[E0599]: no method named `f` found for unit type `()` in the current scope
   --> $DIR/shadowed-trait-methods.rs:13:8
    |
+LL |     pub trait T { fn f(&self) {} }
+   |                      - the method is available for `()` here
+...
 LL |     ().f()
    |        ^ method not found in `()`
    |
diff --git a/src/test/ui/suggestions/import-trait-for-method-call.rs b/src/test/ui/suggestions/import-trait-for-method-call.rs
@@ -0,0 +1,9 @@
+use std::hash::BuildHasher;
+
+fn next_u64() -> u64 {
+    let bh = std::collections::hash_map::RandomState::new();
+    let h = bh.build_hasher();
+    h.finish() //~ ERROR no method named `finish` found for struct `DefaultHasher`
+}
+
+fn main() {}
diff --git a/src/test/ui/suggestions/import-trait-for-method-call.stderr b/src/test/ui/suggestions/import-trait-for-method-call.stderr
@@ -0,0 +1,20 @@
+error[E0599]: no method named `finish` found for struct `DefaultHasher` in the current scope
+  --> $DIR/import-trait-for-method-call.rs:6:7
+   |
+LL |     h.finish()
+   |       ^^^^^^ method not found in `DefaultHasher`
+   | 
+  ::: $SRC_DIR/core/src/hash/mod.rs:LL:COL
+   |
+LL |     fn finish(&self) -> u64;
+   |        ------ the method is available for `DefaultHasher` here
+   |
+   = help: items from traits can only be used if the trait is in scope
+help: the following trait is implemented but not in scope; perhaps add a `use` for it:
+   |
+LL | use std::hash::Hasher;
+   |
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0599`.
diff --git a/src/test/ui/traits/item-privacy.stderr b/src/test/ui/traits/item-privacy.stderr
@@ -20,6 +20,9 @@ error[E0599]: no method named `b` found for struct `S` in the current scope
 LL | struct S;
    | --------- method `b` not found for this
 ...
+LL |         fn b(&self) { }
+   |            - the method is available for `S` here
+...
 LL |     S.b();
    |       ^ method not found in `S`
    |

Original file line number	Diff line number	Diff line change
`@@ -37,6 +37,9 @@ LL \| use no_method_suggested_traits::Reexported;`
`37`	`37`	error[E0599]: no method named `method` found for type `char` in the current scope
`38`	`38`	`--> $DIR/no-method-suggested-traits.rs:30:9`
`39`	`39`	`\|`
	`40`	`+LL \| fn method(&self) {}`
	`41`	+ \| ------ the method is available for `char` here
	`42`	`+...`
`40`	`43`	`LL \| 'a'.method();`
`41`	`44`	\| ^^^^^^ method not found in `char`
`42`	`45`	`\|`
@@ -63,6 +66,11 @@ error[E0599]: no method named `method` found for type `i32` in the current scope
`63`	`66`	`\|`
`64`	`67`	`LL \| 1i32.method();`
`65`	`68`	\| ^^^^^^ method not found in `i32`
	`69`	`+ \|`
	`70`	`+ ::: $DIR/auxiliary/no_method_suggested_traits.rs:8:12`
	`71`	`+ \|`
	`72`	`+LL \| fn method(&self) {}`
	`73`	+ \| ------ the method is available for `i32` here
`66`	`74`	`\|`
`67`	`75`	`= help: items from traits can only be used if the trait is in scope`
`68`	`76`	help: the following trait is implemented but not in scope; perhaps add a `use` for it:
Original file line number	Diff line number	Diff line change
@@ -3,6 +3,11 @@ error[E0599]: no method named `a` found for unit type `()` in the current scope
`3`	`3`	`\|`
`4`	`4`	`LL \| ().a();`
`5`	`5`	\| ^ method not found in `()`
	`6`	`+ \|`
	`7`	`+ ::: $DIR/auxiliary/xcrate-issue-43189-a.rs:5:8`
	`8`	`+ \|`
	`9`	`+LL \| fn a(&self) {}`
	`10`	+ \| - the method is available for `()` here
`6`	`11`	`\|`
`7`	`12`	`= help: items from traits can only be used if the trait is in scope`
`8`	`13`	help: the following trait is implemented but not in scope; perhaps add a `use` for it:
Original file line number	Diff line number	Diff line change
@@ -3,6 +3,11 @@ error[E0599]: no method named `trait_method` found for struct `FooStruct` in the
`3`	`3`	`\|`
`4`	`4`	`LL \| reexported_trait::FooStruct.trait_method();`
`5`	`5`	\| ^^^^^^^^^^^^ method not found in `FooStruct`
	`6`	`+ \|`
	`7`	`+ ::: $DIR/auxiliary/reexported-trait.rs:3:12`
	`8`	`+ \|`
	`9`	`+LL \| fn trait_method(&self) {`
	`10`	+ \| ------------ the method is available for `FooStruct` here
`6`	`11`	`\|`
`7`	`12`	`= help: items from traits can only be used if the trait is in scope`
`8`	`13`	help: the following trait is implemented but not in scope; perhaps add a `use` for it:
@@ -15,6 +20,11 @@ error[E0599]: no method named `trait_method_b` found for struct `FooStruct` in t
`15`	`20`	`\|`
`16`	`21`	`LL \| reexported_trait::FooStruct.trait_method_b();`
`17`	`22`	\| ^^^^^^^^^^^^^^ method not found in `FooStruct`
	`23`	`+ \|`
	`24`	`+ ::: $DIR/auxiliary/reexported-trait.rs:7:12`
	`25`	`+ \|`
	`26`	`+LL \| fn trait_method_b(&self) {`
	`27`	+ \| -------------- the method is available for `FooStruct` here
`18`	`28`	`\|`
`19`	`29`	`= help: items from traits can only be used if the trait is in scope`
`20`	`30`	help: the following trait is implemented but not in scope; perhaps add a `use` for it:
Original file line number	Diff line number	Diff line change
`@@ -1,6 +1,9 @@`
`1`	`1`	error[E0599]: no method named `foobar` found for type `u32` in the current scope
`2`	`2`	`--> $DIR/trait-import-suggestions.rs:22:11`
`3`	`3`	`\|`
	`4`	`+LL \| fn foobar(&self) { }`
	`5`	+ \| ------ the method is available for `u32` here
	`6`	`+...`
`4`	`7`	`LL \| x.foobar();`
`5`	`8`	\| ^^^^^^ method not found in `u32`
`6`	`9`	`\|`
`@@ -11,6 +14,9 @@ LL \| x.foobar();`
`11`	`14`	error[E0599]: no method named `bar` found for type `u32` in the current scope
`12`	`15`	`--> $DIR/trait-import-suggestions.rs:28:7`
`13`	`16`	`\|`
	`17`	`+LL \| fn bar(&self) { }`
	`18`	+ \| --- the method is available for `u32` here
	`19`	`+...`
`14`	`20`	`LL \| x.bar();`
`15`	`21`	\| ^^^ method not found in `u32`
`16`	`22`	`\|`
Original file line number	Diff line number	Diff line change
`@@ -1,6 +1,9 @@`
`1`	`1`	error[E0599]: no method named `f` found for unit type `()` in the current scope
`2`	`2`	`--> $DIR/shadowed-trait-methods.rs:13:8`
`3`	`3`	`\|`
	`4`	`+LL \| pub trait T { fn f(&self) {} }`
	`5`	+ \| - the method is available for `()` here
	`6`	`+...`
`4`	`7`	`LL \| ().f()`
`5`	`8`	\| ^ method not found in `()`
`6`	`9`	`\|`