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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
commit698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch)
tree173a775858bd501c378080a10dca74132f05bc50 /src/test/ui/impl-unused-tps.rs
parentInitial commit. (diff)
downloadrustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz
rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/test/ui/impl-unused-tps.rs')
-rw-r--r--src/test/ui/impl-unused-tps.rs62
1 files changed, 62 insertions, 0 deletions
diff --git a/src/test/ui/impl-unused-tps.rs b/src/test/ui/impl-unused-tps.rs
new file mode 100644
index 000000000..7cc1ae613
--- /dev/null
+++ b/src/test/ui/impl-unused-tps.rs
@@ -0,0 +1,62 @@
+trait Foo<A> {
+ fn get(&self, A: &A) { }
+}
+
+trait Bar {
+ type Out;
+}
+
+impl<T> Foo<T> for [isize;0] {
+ // OK, T is used in `Foo<T>`.
+}
+
+impl<T,U> Foo<T> for [isize;1] {
+ //~^ ERROR the type parameter `U` is not constrained
+}
+
+impl<T,U> Foo<T> for [isize;2] where T : Bar<Out=U> {
+ // OK, `U` is now constrained by the output type parameter.
+}
+
+impl<T:Bar<Out=U>,U> Foo<T> for [isize;3] {
+ // OK, same as above but written differently.
+}
+
+impl<T,U> Foo<T> for U {
+ // OK, T, U are used everywhere. Note that the coherence check
+ // hasn't executed yet, so no errors about overlap.
+}
+
+impl<T,U> Bar for T {
+ //~^ ERROR the type parameter `U` is not constrained
+
+ type Out = U;
+
+ // Using `U` in an associated type within the impl is not good enough!
+}
+
+impl<T,U> Bar for T
+ where T : Bar<Out=U>
+{
+ //~^^^ ERROR the type parameter `U` is not constrained
+
+ // This crafty self-referential attempt is still no good.
+}
+
+impl<T,U,V> Foo<T> for T
+ where (T,U): Bar<Out=V>
+{
+ //~^^^ ERROR the type parameter `U` is not constrained
+ //~| ERROR the type parameter `V` is not constrained
+
+ // Here, `V` is bound by an output type parameter, but the inputs
+ // are not themselves constrained.
+}
+
+impl<T,U,V> Foo<(T,U)> for T
+ where (T,U): Bar<Out=V>
+{
+ // As above, but both T and U ARE constrained.
+}
+
+fn main() { }