1 files changed, 21 insertions, 0 deletions

diff --git a/crates/hir_ty/src/consts.rs b/crates/hir_ty/src/consts.rs
new file mode 100644
index 000000000..0044b1cff
--- /dev/null
+++ b/crates/hir_ty/src/consts.rs
@@ -0,0 +1,21 @@
+//! Handling of concrete const values
+
+/// A concrete constant value
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum ConstScalar {
+    // for now, we only support the trivial case of constant evaluating the length of an array
+    // Note that this is u64 because the target usize may be bigger than our usize
+    Usize(u64),
+
+    /// Case of an unknown value that rustc might know but we don't
+    Unknown,
+}
+
+impl std::fmt::Display for ConstScalar {
+    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
+        match self {
+            ConstScalar::Usize(us) => write!(fmt, "{}", us),
+            ConstScalar::Unknown => write!(fmt, "_"),
+        }
+    }
+}