Auto merge of #64546 - weiznich:bugfix/rfc-2451-rerebalance-tests, r=…

…nikomatsakis

Bugfix/rfc 2451 rerebalance tests

r? @nikomatsakis

Fixes #64412
Depends/Contains on #64414

cc #55437 and #63599

src/librustc/traits/coherence.rs

@@ -378,7 +378,15 @@ fn orphan_check_trait_ref<'tcx>(
         //      Let Ti be the first such type.
         //     - No uncovered type parameters P1..=Pn may appear in T0..Ti (excluding Ti)
         //
-        for input_ty in trait_ref.input_types() {
+        fn uncover_fundamental_ty(ty: Ty<'_>) -> Vec<Ty<'_>> {
+            if fundamental_ty(ty) {
+                ty.walk_shallow().flat_map(|ty| uncover_fundamental_ty(ty)).collect()
+            } else {
+                vec![ty]
+            }
+        }
+
+        for input_ty in trait_ref.input_types().flat_map(uncover_fundamental_ty) {
             debug!("orphan_check_trait_ref: check ty `{:?}`", input_ty);
             if ty_is_local(tcx, input_ty, in_crate) {
                 debug!("orphan_check_trait_ref: ty_is_local `{:?}`", input_ty);

src/test/ui/coherence/auxiliary/coherence_lib.rs

@@ -5,11 +5,11 @@ pub trait Remote {
 }
 
 pub trait Remote1<T> {
-    fn foo(&self, t: T) { }
+    fn foo(&self, _t: T) { }
 }
 
 pub trait Remote2<T, U> {
-    fn foo(&self, t: T, u: U) { }
+    fn foo(&self, _t: T, _u: U) { }
 }
 
 pub struct Pair<T,U>(T,U);

src/test/ui/coherence/impl-foreign[foreign]-for-foreign.rs

@@ -0,0 +1,17 @@
+#![feature(re_rebalance_coherence)]
+
+// compile-flags:--crate-name=test
+// aux-build:coherence_lib.rs
+
+extern crate coherence_lib as lib;
+use lib::*;
+use std::rc::Rc;
+
+struct Local;
+
+impl Remote1<u32> for f64 {
+    //~^ ERROR only traits defined in the current crate
+    // | can be implemented for arbitrary types [E0117]
+}
+
+fn main() {}

src/test/ui/coherence/impl-foreign[foreign]-for-foreign.stderr

@@ -0,0 +1,12 @@
+error[E0117]: only traits defined in the current crate can be implemented for arbitrary types
+  --> $DIR/impl-foreign[foreign]-for-foreign.rs:12:1
+   |
+LL | impl Remote1<u32> for f64 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^ impl doesn't use types inside crate
+   |
+   = note: the impl does not reference only types defined in this crate
+   = note: define and implement a trait or new type instead
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0117`.

src/test/ui/coherence/impl-foreign[foreign]-for-local.rs

@@ -0,0 +1,16 @@
+#![feature(re_rebalance_coherence)]
+
+// compile-flags:--crate-name=test
+// aux-build:coherence_lib.rs
+// check-pass
+
+extern crate coherence_lib as lib;
+use lib::*;
+use std::rc::Rc;
+
+struct Local;
+
+impl Remote1<u32> for Local {
+}
+
+fn main() {}

src/test/ui/coherence/impl[t]-foreign[foreign[t]_local]-for-foreign.rs

@@ -0,0 +1,14 @@
+#![feature(re_rebalance_coherence)]
+
+// check-pass
+// compile-flags:--crate-name=test
+// aux-build:coherence_lib.rs
+
+extern crate coherence_lib as lib;
+use lib::*;
+use std::rc::Rc;
+
+struct Local;
+impl<T> Remote2<Rc<T>, Local> for usize { }
+
+fn main() {}

src/test/ui/coherence/impl[t]-foreign[foreign]-for-fundamental[t].rs

@@ -0,0 +1,20 @@
+#![feature(re_rebalance_coherence)]
+
+// compile-flags:--crate-name=test
+// aux-build:coherence_lib.rs
+
+extern crate coherence_lib as lib;
+use lib::*;
+use std::rc::Rc;
+
+struct Local;
+
+impl<T> Remote1<u32> for Box<T> {
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
+}
+
+impl<'a, T> Remote1<u32> for &'a T {
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
+}
+
+fn main() {}

src/test/ui/coherence/impl[t]-foreign[foreign]-for-fundamental[t].stderr

@@ -0,0 +1,19 @@
+error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
+  --> $DIR/impl[t]-foreign[foreign]-for-fundamental[t].rs:12:1
+   |
+LL | impl<T> Remote1<u32> for Box<T> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `T` must be used as the type parameter for some local type
+   |
+   = note: only traits defined in the current crate can be implemented for a type parameter
+
+error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
+  --> $DIR/impl[t]-foreign[foreign]-for-fundamental[t].rs:16:1
+   |
+LL | impl<'a, T> Remote1<u32> for &'a T {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `T` must be used as the type parameter for some local type
+   |
+   = note: only traits defined in the current crate can be implemented for a type parameter
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0210`.

src/test/ui/coherence/impl[t]-foreign[foreign]-for-t.rs

@@ -0,0 +1,16 @@
+#![feature(re_rebalance_coherence)]
+
+// compile-flags:--crate-name=test
+// aux-build:coherence_lib.rs
+
+extern crate coherence_lib as lib;
+use lib::*;
+use std::rc::Rc;
+
+struct Local;
+
+impl<T> Remote1<u32> for T {
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
+}
+
+fn main() {}

src/test/ui/coherence/impl[t]-foreign[foreign]-for-t.stderr

@@ -0,0 +1,11 @@
+error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
+  --> $DIR/impl[t]-foreign[foreign]-for-t.rs:12:1
+   |
+LL | impl<T> Remote1<u32> for T {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `T` must be used as the type parameter for some local type
+   |
+   = note: only traits defined in the current crate can be implemented for a type parameter
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0210`.

src/test/ui/coherence/impl[t]-foreign[fundamental[t]]-for-foreign.rs

@@ -0,0 +1,20 @@
+#![feature(re_rebalance_coherence)]
+
+// compile-flags:--crate-name=test
+// aux-build:coherence_lib.rs
+
+extern crate coherence_lib as lib;
+use lib::*;
+use std::rc::Rc;
+
+struct Local;
+
+impl<T> Remote1<Box<T>> for u32 {
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
+}
+
+impl<'a, T> Remote1<&'a T> for u32 {
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
+}
+
+fn main() {}

src/test/ui/coherence/impl[t]-foreign[fundamental[t]]-for-foreign.stderr

@@ -0,0 +1,19 @@
+error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
+  --> $DIR/impl[t]-foreign[fundamental[t]]-for-foreign.rs:12:1
+   |
+LL | impl<T> Remote1<Box<T>> for u32 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `T` must be used as the type parameter for some local type
+   |
+   = note: only traits defined in the current crate can be implemented for a type parameter
+
+error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
+  --> $DIR/impl[t]-foreign[fundamental[t]]-for-foreign.rs:16:1
+   |
+LL | impl<'a, T> Remote1<&'a T> for u32 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `T` must be used as the type parameter for some local type
+   |
+   = note: only traits defined in the current crate can be implemented for a type parameter
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0210`.

src/test/ui/coherence/impl[t]-foreign[fundamental[t]]-for-fundamental[t].rs

@@ -0,0 +1,19 @@
+#![feature(re_rebalance_coherence)]
+
+// compile-flags:--crate-name=test
+// aux-build:coherence_lib.rs
+
+extern crate coherence_lib as lib;
+use lib::*;
+use std::rc::Rc;
+
+struct Local;
+
+impl<'a, T> Remote1<Box<T>> for &'a T {
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
+}
+impl<'a, T> Remote1<&'a T> for Box<T> {
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
+}
+
+fn main() {}

src/test/ui/coherence/impl[t]-foreign[fundamental[t]]-for-fundamental[t].stderr

@@ -0,0 +1,19 @@
+error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
+  --> $DIR/impl[t]-foreign[fundamental[t]]-for-fundamental[t].rs:12:1
+   |
+LL | impl<'a, T> Remote1<Box<T>> for &'a T {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `T` must be used as the type parameter for some local type
+   |
+   = note: only traits defined in the current crate can be implemented for a type parameter
+
+error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
+  --> $DIR/impl[t]-foreign[fundamental[t]]-for-fundamental[t].rs:15:1
+   |
+LL | impl<'a, T> Remote1<&'a T> for Box<T> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `T` must be used as the type parameter for some local type
+   |
+   = note: only traits defined in the current crate can be implemented for a type parameter
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0210`.

src/test/ui/coherence/impl[t]-foreign[fundamental[t]]-for-local.rs

@@ -0,0 +1,17 @@
+#![feature(re_rebalance_coherence)]
+
+// compile-flags:--crate-name=test
+// aux-build:coherence_lib.rs
+// check-pass
+
+extern crate coherence_lib as lib;
+use lib::*;
+use std::rc::Rc;
+
+struct Local;
+
+impl<T> Remote1<Box<T>> for Local {}
+
+impl<'a, T> Remote1<&'a T> for Local {}
+
+fn main() {}

src/test/ui/coherence/impl[t]-foreign[fundamental[t]]-for-t.rs

@@ -0,0 +1,19 @@
+#![feature(re_rebalance_coherence)]
+
+// compile-flags:--crate-name=test
+// aux-build:coherence_lib.rs
+
+extern crate coherence_lib as lib;
+use lib::*;
+use std::rc::Rc;
+
+struct Local;
+
+impl<T> Remote1<Box<T>> for T {
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
+}
+impl<'a, T> Remote1<&'a T> for T {
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
+}
+
+fn main() {}

src/test/ui/coherence/impl[t]-foreign[fundamental[t]]-for-t.stderr

@@ -0,0 +1,19 @@
+error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
+  --> $DIR/impl[t]-foreign[fundamental[t]]-for-t.rs:12:1
+   |
+LL | impl<T> Remote1<Box<T>> for T {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `T` must be used as the type parameter for some local type
+   |
+   = note: only traits defined in the current crate can be implemented for a type parameter
+
+error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
+  --> $DIR/impl[t]-foreign[fundamental[t]]-for-t.rs:15:1
+   |
+LL | impl<'a, T> Remote1<&'a T> for T {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `T` must be used as the type parameter for some local type
+   |
+   = note: only traits defined in the current crate can be implemented for a type parameter
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0210`.

src/test/ui/coherence/impl[t]-foreign[fundamental[t]_local]-for-foreign.rs

@@ -0,0 +1,20 @@
+#![feature(re_rebalance_coherence)]
+
+// compile-flags:--crate-name=test
+// aux-build:coherence_lib.rs
+
+extern crate coherence_lib as lib;
+use lib::*;
+use std::rc::Rc;
+
+struct Local;
+
+impl<T> Remote2<Box<T>, Local> for u32 {
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
+}
+
+impl<'a, T> Remote2<&'a T, Local> for u32 {
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
+}
+
+fn main() {}

src/test/ui/coherence/impl[t]-foreign[fundamental[t]_local]-for-foreign.stderr

@@ -0,0 +1,19 @@
+error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
+  --> $DIR/impl[t]-foreign[fundamental[t]_local]-for-foreign.rs:12:1
+   |
+LL | impl<T> Remote2<Box<T>, Local> for u32 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `T` must be used as the type parameter for some local type
+   |
+   = note: only traits defined in the current crate can be implemented for a type parameter
+
+error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
+  --> $DIR/impl[t]-foreign[fundamental[t]_local]-for-foreign.rs:16:1
+   |
+LL | impl<'a, T> Remote2<&'a T, Local> for u32 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `T` must be used as the type parameter for some local type
+   |
+   = note: only traits defined in the current crate can be implemented for a type parameter
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0210`.

src/test/ui/coherence/impl[t]-foreign[local]-for-foreign.rs

@@ -0,0 +1,16 @@
+#![feature(re_rebalance_coherence)]
+
+// compile-flags:--crate-name=test
+// aux-build:coherence_lib.rs
+// check-pass
+
+extern crate coherence_lib as lib;
+use lib::*;
+use std::rc::Rc;
+
+struct Local;
+
+impl<T> Remote1<Local> for Rc<T> {}
+impl<T> Remote1<Local> for Vec<Box<T>> {}
+
+fn main() {}

src/test/ui/coherence/impl[t]-foreign[local]-for-fundamental[t].rs

@@ -0,0 +1,20 @@
+#![feature(re_rebalance_coherence)]
+
+// compile-flags:--crate-name=test
+// aux-build:coherence_lib.rs
+
+extern crate coherence_lib as lib;
+use lib::*;
+use std::rc::Rc;
+
+struct Local;
+
+impl<T> Remote1<Local> for Box<T> {
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
+}
+
+impl<T> Remote1<Local> for &T {
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
+}
+
+fn main() {}