Rename the ConstS::val field as kind.

And likewise for the `Const::val` method.

Because its type is called `ConstKind`. Also `val` is a confusing name
because `ConstKind` is an enum with seven variants, one of which is
called `Value`. Also, this gives consistency with `TyS` and `PredicateS`
which have `kind` fields.

The commit also renames a few `Const` variables from `val` to `c`, to
avoid confusion with the `ConstKind::Value` variant.

Author: nnethercote

clippy_lints/src/large_const_arrays.rs

@@ -53,7 +53,7 @@ impl<'tcx> LateLintPass<'tcx> for LargeConstArrays {
             if let ItemKind::Const(hir_ty, _) = &item.kind;
             let ty = hir_ty_to_ty(cx.tcx, hir_ty);
             if let ty::Array(element_type, cst) = ty.kind();
-            if let ConstKind::Value(ConstValue::Scalar(element_count)) = cst.val();
+            if let ConstKind::Value(ConstValue::Scalar(element_count)) = cst.kind();
             if let Ok(element_count) = element_count.to_machine_usize(&cx.tcx);
             if let Ok(element_size) = cx.layout_of(*element_type).map(|l| l.size.bytes());
             if self.maximum_allowed_size < element_count * element_size;

clippy_lints/src/large_stack_arrays.rs

@@ -43,7 +43,7 @@ impl<'tcx> LateLintPass<'tcx> for LargeStackArrays {
         if_chain! {
             if let ExprKind::Repeat(_, _) = expr.kind;
             if let ty::Array(element_type, cst) = cx.typeck_results().expr_ty(expr).kind();
-            if let ConstKind::Value(ConstValue::Scalar(element_count)) = cst.val();
+            if let ConstKind::Value(ConstValue::Scalar(element_count)) = cst.kind();
             if let Ok(element_count) = element_count.to_machine_usize(&cx.tcx);
             if let Ok(element_size) = cx.layout_of(*element_type).map(|l| l.size.bytes());
             if self.maximum_allowed_size < element_count * element_size;

clippy_utils/src/consts.rs

@@ -582,7 +582,7 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
 
 pub fn miri_to_const(result: ty::Const<'_>) -> Option<Constant> {
     use rustc_middle::mir::interpret::ConstValue;
-    match result.val() {
+    match result.kind() {
         ty::ConstKind::Value(ConstValue::Scalar(Scalar::Int(int))) => {
             match result.ty().kind() {
                 ty::Bool => Some(Constant::Bool(int == ScalarInt::TRUE)),