chore: Allow count of elements in repeated-element array syntax to be any static Field

crates/nargo_cli/tests/compile_success_empty/slice_as_array/Nargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "slice_as_array"
+type = "bin"
+authors = [""]
+compiler_version = "0.10.3"
+
+[dependencies]

crates/nargo_cli/tests/compile_success_empty/slice_as_array/src/main.nr

@@ -0,0 +1,8 @@
+fn main() {
+    let slice = [1, 2, 3];
+    let array: [Field; 3] = slice.as_array();
+
+    assert(array[0] == 1);
+    assert(array[1] == 2);
+    assert(array[2] == 3);
+}

noir_stdlib/src/array.nr

@@ -83,3 +83,12 @@ impl<T, N> [T; N] {
         ret
     }
 }
+
+fn repeated<T>(element: T, length: Field) -> [T] {
+    crate::assert_constant(length);
+    let mut result = [];
+    for _ in 0..length {
+        result = result.push_back(element);
+    }
+    result
+}

noir_stdlib/src/slice.nr

@@ -1,4 +1,9 @@
 impl<T> [T] {
+    fn as_array<N>(self) -> [T; N] {
+        assert(self.len() == N);
+        unsafe::slice_as_array(self)
+    }
+
     /// Push a new element to the end of the slice, returning a
     /// new slice with a length one greater than the
     /// original unmodified slice.
@@ -53,3 +58,11 @@ impl<T> [T] {
         self
     }
 }
+
+mod unsafe {
+    // This is a private built-in compiler function `slice_as_array`.
+    // It's not intended for general use and should not be used directly.
+    // Users should prefer to use `slice.as_array()` instead 
+    #[builtin(slice_as_array)]
+    fn slice_as_array<T, N>(_slice: [T]) -> [T; N] {}
+}