require simd_insert, simd_extract indices to be constants

compiler/rustc_borrowck/src/session_diagnostics.rs

@@ -454,8 +454,10 @@ pub(crate) enum TypeNoCopy<'a, 'tcx> {
 }
 
 #[derive(Diagnostic)]
-#[diag(borrowck_simd_shuffle_last_const)]
-pub(crate) struct SimdShuffleLastConst {
+#[diag(borrowck_simd_intrinsic_arg_const)]
+pub(crate) struct SimdIntrinsicArgConst {
     #[primary_span]
     pub span: Span,
+    pub arg: usize,
+    pub intrinsic: String,
 }