Check that value is explicitly none

src/test/ui/issues/issue-80371.rs

@@ -0,0 +1,15 @@
+#![crate_type = "lib"]
+
+pub struct Header<'a> {
+    pub value: &'a [u8],
+}
+
+pub fn test() {
+    let headers = [Header{value: &[]}; 128];
+    //~^ ERROR the trait bound
+}
+
+pub fn test2() {
+    let headers = [Header{value: &[0]}; 128];
+    //~^ ERROR the trait bound
+}

src/test/ui/issues/issue-80371.stderr

@@ -0,0 +1,23 @@
+error[E0277]: the trait bound `Header<'_>: Copy` is not satisfied
+  --> $DIR/issue-80371.rs:8:19
+   |
+LL |     let headers = [Header{value: &[]}; 128];
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `Header<'_>`
+   |
+   = note: the `Copy` trait is required because the repeated element will be copied
+   = note: this array initializer can be evaluated at compile-time, see issue #49147 <https://github.com/rust-lang/rust/issues/49147> for more information
+   = help: add `#![feature(const_in_array_repeat_expressions)]` to the crate attributes to enable
+
+error[E0277]: the trait bound `Header<'_>: Copy` is not satisfied
+  --> $DIR/issue-80371.rs:13:19
+   |
+LL |     let headers = [Header{value: &[0]}; 128];
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `Header<'_>`
+   |
+   = note: the `Copy` trait is required because the repeated element will be copied
+   = note: this array initializer can be evaluated at compile-time, see issue #49147 <https://github.com/rust-lang/rust/issues/49147> for more information
+   = help: add `#![feature(const_in_array_repeat_expressions)]` to the crate attributes to enable
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.