Fix ICE in miri_to_const

Author: Jarcho

clippy_utils/src/consts.rs

@@ -619,32 +619,24 @@ pub fn miri_to_const<'tcx>(tcx: TyCtxt<'tcx>, result: mir::ConstantKind<'tcx>) -
         },
         mir::ConstantKind::Val(ConstValue::ByRef { alloc, offset: _ }, _) => match result.ty().kind() {
             ty::Array(sub_type, len) => match sub_type.kind() {
-                ty::Float(FloatTy::F32) => match len.to_valtree().try_to_machine_usize(tcx) {
+                ty::Float(FloatTy::F32) => match len.kind().try_to_machine_usize(tcx) {
                     Some(len) => alloc
                         .inner()
                         .inspect_with_uninit_and_ptr_outside_interpreter(0..(4 * usize::try_from(len).unwrap()))
                         .to_owned()
-                        .chunks(4)
-                        .map(|chunk| {
-                            Some(Constant::F32(f32::from_le_bytes(
-                                chunk.try_into().expect("this shouldn't happen"),
-                            )))
-                        })
+                        .array_chunks::<4>()
+                        .map(|&chunk| Some(Constant::F32(f32::from_le_bytes(chunk))))
                         .collect::<Option<Vec<Constant>>>()
                         .map(Constant::Vec),
                     _ => None,
                 },
-                ty::Float(FloatTy::F64) => match len.to_valtree().try_to_machine_usize(tcx) {
+                ty::Float(FloatTy::F64) => match len.kind().try_to_machine_usize(tcx) {
                     Some(len) => alloc
                         .inner()
                         .inspect_with_uninit_and_ptr_outside_interpreter(0..(8 * usize::try_from(len).unwrap()))
                         .to_owned()
-                        .chunks(8)
-                        .map(|chunk| {
-                            Some(Constant::F64(f64::from_le_bytes(
-                                chunk.try_into().expect("this shouldn't happen"),
-                            )))
-                        })
+                        .array_chunks::<8>()
+                        .map(|&chunk| Some(Constant::F64(f64::from_le_bytes(chunk))))
                         .collect::<Option<Vec<Constant>>>()
                         .map(Constant::Vec),
                     _ => None,

clippy_utils/src/lib.rs

@@ -1,3 +1,4 @@
+#![feature(array_chunks)]
 #![feature(box_patterns)]
 #![feature(control_flow_enum)]
 #![feature(let_else)]

tests/ui/crashes/ice-9238.rs

@@ -0,0 +1,12 @@
+#![allow(incomplete_features)]
+#![feature(generic_const_exprs)]
+#![warn(clippy::branches_sharing_code)]
+
+const fn f() -> usize {
+    2
+}
+const C: [f64; f()] = [0f64; f()];
+
+fn main() {
+    let _ = if true { C[0] } else { C[1] };
+}