Use ScalarInt as early as possible...

...instead of carrying around ty::Const and erroring later

Author: oli-obk

compiler/rustc_middle/src/ty/util.rs

@@ -23,6 +23,8 @@ use rustc_target::abi::{Integer, Size, TargetDataLayout};
 use smallvec::SmallVec;
 use std::{fmt, iter};
 
+use super::ScalarInt;
+
 #[derive(Copy, Clone, Debug)]
 pub struct Discr<'tcx> {
     /// Bit representation of the discriminant (e.g., `-128i8` is `0xFF_u128`).
@@ -616,40 +618,38 @@ impl<'tcx> TypeFolder<'tcx> for OpaqueTypeExpander<'tcx> {
 impl<'tcx> ty::TyS<'tcx> {
     /// Returns the maximum value for the given numeric type (including `char`s)
     /// or returns `None` if the type is not numeric.
-    pub fn numeric_max_val(&'tcx self, tcx: TyCtxt<'tcx>) -> Option<&'tcx ty::Const<'tcx>> {
-        let val = match self.kind() {
+    pub fn numeric_max_val(&'tcx self, tcx: TyCtxt<'tcx>) -> Option<ScalarInt> {
+        match self.kind() {
             ty::Int(_) | ty::Uint(_) => {
                 let (size, signed) = int_size_and_signed(tcx, self);
                 let val = if signed { signed_max(size) as u128 } else { unsigned_max(size) };
-                Some(val)
+                Some(ScalarInt::from_uint(val, size))
             }
-            ty::Char => Some(std::char::MAX as u128),
+            ty::Char => Some(ScalarInt::from(std::char::MAX)),
             ty::Float(fty) => Some(match fty {
-                ty::FloatTy::F32 => rustc_apfloat::ieee::Single::INFINITY.to_bits(),
-                ty::FloatTy::F64 => rustc_apfloat::ieee::Double::INFINITY.to_bits(),
+                ty::FloatTy::F32 => ScalarInt::from(rustc_apfloat::ieee::Single::INFINITY),
+                ty::FloatTy::F64 => ScalarInt::from(rustc_apfloat::ieee::Double::INFINITY),
             }),
             _ => None,
-        };
-        val.map(|v| ty::Const::from_bits(tcx, v, ty::ParamEnv::empty().and(self)))
+        }
     }
 
     /// Returns the minimum value for the given numeric type (including `char`s)
     /// or returns `None` if the type is not numeric.
-    pub fn numeric_min_val(&'tcx self, tcx: TyCtxt<'tcx>) -> Option<&'tcx ty::Const<'tcx>> {
-        let val = match self.kind() {
+    pub fn numeric_min_val(&'tcx self, tcx: TyCtxt<'tcx>) -> Option<ScalarInt> {
+        match self.kind() {
             ty::Int(_) | ty::Uint(_) => {
                 let (size, signed) = int_size_and_signed(tcx, self);
                 let val = if signed { size.truncate(signed_min(size) as u128) } else { 0 };
-                Some(val)
+                Some(ScalarInt::from_uint(val, size))
             }
-            ty::Char => Some(0),
+            ty::Char => Some(ScalarInt::from('\0')),
             ty::Float(fty) => Some(match fty {
-                ty::FloatTy::F32 => (-::rustc_apfloat::ieee::Single::INFINITY).to_bits(),
-                ty::FloatTy::F64 => (-::rustc_apfloat::ieee::Double::INFINITY).to_bits(),
+                ty::FloatTy::F32 => ScalarInt::from(-::rustc_apfloat::ieee::Single::INFINITY),
+                ty::FloatTy::F64 => ScalarInt::from(-::rustc_apfloat::ieee::Double::INFINITY),
             }),
             _ => None,
-        };
-        val.map(|v| ty::Const::from_bits(tcx, v, ty::ParamEnv::empty().and(self)))
+        }
     }
 
     /// Checks whether values of this type `T` are *moved* or *copied*

compiler/rustc_mir_build/src/thir/pattern/mod.rs

@@ -21,7 +21,7 @@ use rustc_middle::mir::UserTypeProjection;
 use rustc_middle::mir::{BorrowKind, Field, Mutability};
 use rustc_middle::thir::{Ascription, BindingMode, FieldPat, Pat, PatKind, PatRange, PatTyProj};
 use rustc_middle::ty::subst::{GenericArg, SubstsRef};
-use rustc_middle::ty::{self, AdtDef, DefIdTree, Region, Ty, TyCtxt, UserType};
+use rustc_middle::ty::{self, AdtDef, DefIdTree, Region, ScalarInt, Ty, TyCtxt, UserType};
 use rustc_span::{Span, Symbol};
 
 use std::cmp::Ordering;
@@ -122,25 +122,14 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
     fn lower_pattern_range(
         &mut self,
         ty: Ty<'tcx>,
-        lo: &'tcx ty::Const<'tcx>,
-        hi: &'tcx ty::Const<'tcx>,
+        lo: ScalarInt,
+        hi: ScalarInt,
         end: RangeEnd,
         span: Span,
     ) -> PatKind<'tcx> {
-        assert_eq!(lo.ty, ty);
-        assert_eq!(hi.ty, ty);
-        let cmp = compare_const_vals(self.tcx, lo, hi, self.param_env, ty);
-        let lo_const = lo;
-        let lo = lo
-            .val
-            .eval(self.tcx, self.param_env)
-            .try_to_scalar_int()
-            .expect("range patterns must be integral");
-        let hi = hi
-            .val
-            .eval(self.tcx, self.param_env)
-            .try_to_scalar_int()
-            .expect("range patterns must be integral");
+        let lo_const = ty::Const::from_value(self.tcx, ConstValue::Scalar(lo.into()), ty);
+        let hi_const = ty::Const::from_value(self.tcx, ConstValue::Scalar(hi.into()), ty);
+        let cmp = compare_const_vals(self.tcx, lo_const, hi_const, self.param_env, ty);
         match (end, cmp) {
             // `x..y` where `x < y`.
             // Non-empty because the range includes at least `x`.
@@ -193,16 +182,18 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         ty: Ty<'tcx>,
         lo: Option<&PatKind<'tcx>>,
         hi: Option<&PatKind<'tcx>>,
-    ) -> Option<(&'tcx ty::Const<'tcx>, &'tcx ty::Const<'tcx>)> {
+    ) -> Option<(ScalarInt, ScalarInt)> {
+        let eval =
+            |value: &ty::Const<'tcx>| value.val.eval(self.tcx, self.param_env).try_to_scalar_int();
         match (lo, hi) {
             (Some(PatKind::Constant { value: lo }), Some(PatKind::Constant { value: hi })) => {
-                Some((lo, hi))
+                Some((eval(lo)?, eval(hi)?))
             }
             (Some(PatKind::Constant { value: lo }), None) => {
-                Some((lo, ty.numeric_max_val(self.tcx)?))
+                Some((eval(lo)?, ty.numeric_max_val(self.tcx)?))
             }
             (None, Some(PatKind::Constant { value: hi })) => {
-                Some((ty.numeric_min_val(self.tcx)?, hi))
+                Some((ty.numeric_min_val(self.tcx)?, eval(hi)?))
             }
             _ => None,
         }

src/tools/clippy/clippy_lints/src/enum_clike.rs

@@ -1,7 +1,6 @@
 //! lint on C-like enums that are `repr(isize/usize)` and have values that
 //! don't fit into an `i32`
 
-use clippy_utils::consts::{miri_to_const, Constant};
 use clippy_utils::diagnostics::span_lint;
 use rustc_hir::{Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass};
@@ -50,8 +49,9 @@ impl<'tcx> LateLintPass<'tcx> for UnportableVariant {
                         .tcx
                         .const_eval_poly(def_id.to_def_id())
                         .ok()
-                        .map(|val| rustc_middle::ty::Const::from_value(cx.tcx, val, ty));
-                    if let Some(Constant::Int(val)) = constant.and_then(miri_to_const) {
+                        .and_then(|c| c.try_to_scalar_int());
+                    if let Some(scalar) = constant {
+                        let val = scalar.to_bits(cx.tcx.layout_of(cx.param_env.and(ty)).unwrap().size).unwrap();
                         if let ty::Adt(adt, _) = ty.kind() {
                             if adt.is_enum() {
                                 ty = adt.repr.discr_type().to_ty(cx.tcx);

src/tools/clippy/clippy_lints/src/matches.rs

@@ -25,6 +25,7 @@ use rustc_hir::{HirIdMap, HirIdSet};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{self, Ty, TyS, VariantDef};
+use rustc_middle::mir::{self, interpret::ConstValue};
 use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::{Span, Spanned};
@@ -1533,11 +1534,17 @@ fn all_ranges<'tcx>(cx: &LateContext<'tcx>, arms: &'tcx [Arm<'_>], ty: Ty<'tcx>)
                 if let PatKind::Range(ref lhs, ref rhs, range_end) = pat.kind {
                     let lhs = match lhs {
                         Some(lhs) => constant(cx, cx.typeck_results(), lhs)?.0,
-                        None => miri_to_const(ty.numeric_min_val(cx.tcx)?)?,
+                        None => miri_to_const(mir::ConstantKind::Val(
+                            ConstValue::Scalar(ty.numeric_min_val(cx.tcx)?.into()),
+                            ty,
+                        ))?,
                     };
                     let rhs = match rhs {
                         Some(rhs) => constant(cx, cx.typeck_results(), rhs)?.0,
-                        None => miri_to_const(ty.numeric_max_val(cx.tcx)?)?,
+                        None => miri_to_const(mir::ConstantKind::Val(
+                            ConstValue::Scalar(ty.numeric_max_val(cx.tcx)?.into()),
+                            ty,
+                        ))?,
                     };
                     let rhs = match range_end {
                         RangeEnd::Included => Bound::Included(rhs),

src/tools/clippy/clippy_utils/src/consts.rs

@@ -7,7 +7,7 @@ use rustc_data_structures::sync::Lrc;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{BinOp, BinOpKind, Block, Expr, ExprKind, HirId, QPath, UnOp};
 use rustc_lint::LateContext;
-use rustc_middle::mir::interpret::Scalar;
+use rustc_middle::mir;
 use rustc_middle::ty::subst::{Subst, SubstsRef};
 use rustc_middle::ty::{self, FloatTy, ScalarInt, Ty, TyCtxt};
 use rustc_middle::{bug, span_bug};
@@ -354,7 +354,7 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
                         None,
                     )
                     .ok()
-                    .map(|val| rustc_middle::ty::Const::from_value(self.lcx.tcx, val, ty))?;
+                    .map(|val| mir::ConstantKind::Val(val, ty))?;
                 let result = miri_to_const(result);
                 if result.is_some() {
                     self.needed_resolution = true;
@@ -505,44 +505,38 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
     }
 }
 
-pub fn miri_to_const(result: &ty::Const<'_>) -> Option<Constant> {
+pub fn miri_to_const(result: mir::ConstantKind<'tcx>) -> Option<Constant> {
     use rustc_middle::mir::interpret::ConstValue;
-    match result.val {
-        ty::ConstKind::Value(ConstValue::Scalar(Scalar::Int(int))) => {
-            match result.ty.kind() {
-                ty::Bool => Some(Constant::Bool(int == ScalarInt::TRUE)),
-                ty::Uint(_) | ty::Int(_) => Some(Constant::Int(int.assert_bits(int.size()))),
+    match *result.ty().kind() {
+        ty::Bool => Some(Constant::Bool(result.try_to_scalar_int()? == ScalarInt::TRUE)),
+        ty::Uint(_) | ty::Int(_) => {
+            let int = result.try_to_scalar_int()?;
+            Some(Constant::Int(int.assert_bits(int.size())))
+        }
                 ty::Float(FloatTy::F32) => Some(Constant::F32(f32::from_bits(
-                    int.try_into().expect("invalid f32 bit representation"),
+            result.try_to_scalar_int()?.try_into().expect("invalid f32 bit representation"),
                 ))),
                 ty::Float(FloatTy::F64) => Some(Constant::F64(f64::from_bits(
-                    int.try_into().expect("invalid f64 bit representation"),
+            result.try_to_scalar_int()?.try_into().expect("invalid f64 bit representation"),
                 ))),
-                ty::RawPtr(type_and_mut) => {
-                    if let ty::Uint(_) = type_and_mut.ty.kind() {
-                        return Some(Constant::RawPtr(int.assert_bits(int.size())));
+        ty::RawPtr(_) => {
+            let int = result.try_to_scalar_int()?;
+            Some(Constant::RawPtr(int.assert_bits(int.size())))
                     }
-                    None
-                },
-                // FIXME: implement other conversions.
-                _ => None,
-            }
-        },
-        ty::ConstKind::Value(ConstValue::Slice { data, start, end }) => match result.ty.kind() {
             ty::Ref(_, tam, _) => match tam.kind() {
-                ty::Str => String::from_utf8(
-                    data.inspect_with_uninit_and_ptr_outside_interpreter(start..end)
-                        .to_owned(),
+            ty::Str => match result.try_to_value()? {
+                ConstValue::Slice { data, start, end } => String::from_utf8(
+                    data.inspect_with_uninit_and_ptr_outside_interpreter(start..end).to_owned(),
                 )
                 .ok()
                 .map(Constant::Str),
                 _ => None,
             },
             _ => None,
         },
-        ty::ConstKind::Value(ConstValue::ByRef { alloc, offset: _ }) => match result.ty.kind() {
-            ty::Array(sub_type, len) => match sub_type.kind() {
-                ty::Float(FloatTy::F32) => match miri_to_const(len) {
+        ty::Array(sub_type, len) => match result.try_to_value()? {
+            ConstValue::ByRef { alloc, offset: _ } => match sub_type.kind() {
+                ty::Float(FloatTy::F32) => match miri_to_const(len.into()) {
                     Some(Constant::Int(len)) => alloc
                         .inspect_with_uninit_and_ptr_outside_interpreter(0..(4 * len as usize))
                         .to_owned()
@@ -556,7 +550,7 @@ pub fn miri_to_const(result: &ty::Const<'_>) -> Option<Constant> {
                         .map(Constant::Vec),
                     _ => None,
                 },
-                ty::Float(FloatTy::F64) => match miri_to_const(len) {
+                ty::Float(FloatTy::F64) => match miri_to_const(len.into()) {
                     Some(Constant::Int(len)) => alloc
                         .inspect_with_uninit_and_ptr_outside_interpreter(0..(8 * len as usize))
                         .to_owned()