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-rw-r--r--src/test/ui/rfc-2632-const-trait-impl/specialization/non-const-default-const-specialized.rs39
1 files changed, 39 insertions, 0 deletions
diff --git a/src/test/ui/rfc-2632-const-trait-impl/specialization/non-const-default-const-specialized.rs b/src/test/ui/rfc-2632-const-trait-impl/specialization/non-const-default-const-specialized.rs
new file mode 100644
index 000000000..35aa52fbd
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/specialization/non-const-default-const-specialized.rs
@@ -0,0 +1,39 @@
+// Tests that a non-const default impl can be specialized by a const trait impl,
+// but that the default impl cannot be used in a const context.
+
+// run-pass
+
+#![feature(const_trait_impl)]
+#![feature(min_specialization)]
+
+#[const_trait]
+trait Value {
+ fn value() -> u32;
+}
+
+const fn get_value<T: ~const Value>() -> u32 {
+ T::value()
+}
+
+impl<T> Value for T {
+ default fn value() -> u32 {
+ println!("You can't do that (constly)");
+ 0
+ }
+}
+
+struct FortyTwo;
+
+impl const Value for FortyTwo {
+ fn value() -> u32 {
+ 42
+ }
+}
+
+fn main() {
+ let zero = get_value::<()>();
+ assert_eq!(zero, 0);
+
+ const FORTY_TWO: u32 = get_value::<FortyTwo>();
+ assert_eq!(FORTY_TWO, 42);
+}