Add test for issue-62504

src/test/ui/const-generics/issues/issue-62504.rs

@@ -0,0 +1,25 @@
+// Regression test for #62504
+
+#![feature(const_generics)]
+#![allow(incomplete_features)]
+
+trait HasSize {
+    const SIZE: usize;
+}
+
+impl<const X: usize> HasSize for ArrayHolder<{ X }> {
+    const SIZE: usize = X;
+}
+
+struct ArrayHolder<const X: usize>([u32; X]);
+
+impl<const X: usize> ArrayHolder<{ X }> {
+    pub const fn new() -> Self {
+        ArrayHolder([0; Self::SIZE])
+        //~^ ERROR: array lengths can't depend on generic parameters
+    }
+}
+
+fn main() {
+    let mut array = ArrayHolder::new();
+}

src/test/ui/const-generics/issues/issue-62504.stderr

@@ -0,0 +1,8 @@
+error: array lengths can't depend on generic parameters
+  --> $DIR/issue-62504.rs:18:25
+   |
+LL |         ArrayHolder([0; Self::SIZE])
+   |                         ^^^^^^^^^^
+
+error: aborting due to previous error
+