1 files changed, 11 insertions, 0 deletions
diff --git a/src/test/ui/consts/issue-39974.rs b/src/test/ui/consts/issue-39974.rs
new file mode 100644
index 000000000..503647ef4
--- /dev/null
+++ b/src/test/ui/consts/issue-39974.rs
@@ -0,0 +1,11 @@
+const LENGTH: f64 = 2;
+
+struct Thing {
+    f: [[f64; 2]; LENGTH],
+    //~^ ERROR mismatched types
+    //~| expected `usize`, found `f64`
+}
+
+fn main() {
+    let _t = Thing { f: [[0.0, 0.0], [0.0, 0.0], [0.0, 0.0], [0.0, 0.0]] };
+}