mGCA: Validate const literal against expected type

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -35,11 +35,10 @@ use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
 use rustc_infer::traits::DynCompatibilityViolation;
 use rustc_macros::{TypeFoldable, TypeVisitable};
 use rustc_middle::middle::stability::AllowUnstable;
-use rustc_middle::mir::interpret::LitToConstInput;
 use rustc_middle::ty::print::PrintPolyTraitRefExt as _;
 use rustc_middle::ty::{
-    self, Const, GenericArgKind, GenericArgsRef, GenericParamDefKind, Ty, TyCtxt,
-    TypeSuperFoldable, TypeVisitableExt, TypingMode, Upcast, fold_regions,
+    self, Const, GenericArgKind, GenericArgsRef, GenericParamDefKind, LitToConstInput, Ty, TyCtxt,
+    TypeSuperFoldable, TypeVisitableExt, TypingMode, Upcast, const_lit_matches_ty, fold_regions,
 };
 use rustc_middle::{bug, span_bug};
 use rustc_session::lint::builtin::AMBIGUOUS_ASSOCIATED_ITEMS;
@@ -2803,8 +2802,17 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         span: Span,
     ) -> Const<'tcx> {
         let tcx = self.tcx();
+        if let LitKind::Err(guar) = *kind {
+            return ty::Const::new_error(tcx, guar);
+        }
         let input = LitToConstInput { lit: *kind, ty, neg };
-        tcx.at(span).lit_to_const(input)
+        match tcx.at(span).lit_to_const(input) {
+            Some(value) => ty::Const::new_value(tcx, value.valtree, value.ty),
+            None => {
+                let e = tcx.dcx().span_err(span, "type annotations needed for the literal");
+                ty::Const::new_error(tcx, e)
+            }
+        }
     }
 
     #[instrument(skip(self), level = "debug")]
@@ -2833,11 +2841,15 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             _ => None,
         };
 
-        lit_input
-            // Allow the `ty` to be an alias type, though we cannot handle it here, we just go through
-            // the more expensive anon const code path.
-            .filter(|l| !l.ty.has_aliases())
-            .map(|l| tcx.at(expr.span).lit_to_const(l))
+        lit_input.and_then(|l| {
+            if const_lit_matches_ty(tcx, &l.lit, l.ty, l.neg) {
+                tcx.at(expr.span)
+                    .lit_to_const(l)
+                    .map(|value| ty::Const::new_value(tcx, value.valtree, value.ty))
+            } else {
+                None
+            }
+        })
     }
 
     fn require_type_const_attribute(

compiler/rustc_middle/src/mir/interpret/mod.rs

@@ -13,7 +13,7 @@ use std::num::NonZero;
 use std::{fmt, io};
 
 use rustc_abi::{AddressSpace, Align, Endian, HasDataLayout, Size};
-use rustc_ast::{LitKind, Mutability};
+use rustc_ast::Mutability;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sharded::ShardedHashMap;
 use rustc_data_structures::sync::{AtomicU64, Lock};
@@ -73,17 +73,6 @@ impl<'tcx> GlobalId<'tcx> {
     }
 }
 
-/// Input argument for `tcx.lit_to_const`.
-#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash, HashStable)]
-pub struct LitToConstInput<'tcx> {
-    /// The absolute value of the resultant constant.
-    pub lit: LitKind,
-    /// The type of the constant.
-    pub ty: Ty<'tcx>,
-    /// If the constant is negative.
-    pub neg: bool,
-}
-
 #[derive(Copy, Clone, Eq, Hash, Ord, PartialEq, PartialOrd)]
 pub struct AllocId(pub NonZero<u64>);
 

compiler/rustc_middle/src/queries.rs

@@ -112,7 +112,7 @@ use crate::middle::resolve_bound_vars::{ObjectLifetimeDefault, ResolveBoundVars,
 use crate::middle::stability::DeprecationEntry;
 use crate::mir::interpret::{
     EvalStaticInitializerRawResult, EvalToAllocationRawResult, EvalToConstValueResult,
-    EvalToValTreeResult, GlobalId, LitToConstInput,
+    EvalToValTreeResult, GlobalId,
 };
 use crate::mir::mono::{
     CodegenUnit, CollectionMode, MonoItem, MonoItemPartitions, NormalizationErrorInMono,
@@ -135,8 +135,8 @@ use crate::ty::layout::ValidityRequirement;
 use crate::ty::print::PrintTraitRefExt;
 use crate::ty::util::AlwaysRequiresDrop;
 use crate::ty::{
-    self, CrateInherentImpls, GenericArg, GenericArgsRef, PseudoCanonicalInput, SizedTraitKind, Ty,
-    TyCtxt, TyCtxtFeed,
+    self, CrateInherentImpls, GenericArg, GenericArgsRef, LitToConstInput, PseudoCanonicalInput,
+    SizedTraitKind, Ty, TyCtxt, TyCtxtFeed,
 };
 use crate::{dep_graph, mir, thir};
 
@@ -1412,7 +1412,7 @@ rustc_queries! {
     // FIXME get rid of this with valtrees
     query lit_to_const(
         key: LitToConstInput<'tcx>
-    ) -> ty::Const<'tcx> {
+    ) -> Option<ty::Value<'tcx>> {
         desc { "converting literal to const" }
     }
 

compiler/rustc_middle/src/query/erase.rs

@@ -256,6 +256,10 @@ impl Erasable for Option<ty::EarlyBinder<'_, Ty<'_>>> {
     type Storage = [u8; size_of::<Option<ty::EarlyBinder<'static, Ty<'static>>>>()];
 }
 
+impl Erasable for Option<ty::Value<'_>> {
+    type Storage = [u8; size_of::<Option<ty::Value<'static>>>()];
+}
+
 impl Erasable for rustc_hir::MaybeOwner<'_> {
     type Storage = [u8; size_of::<rustc_hir::MaybeOwner<'static>>()];
 }
@@ -441,7 +445,6 @@ impl_erasable_for_single_lifetime_types! {
     rustc_middle::mir::DestructuredConstant,
     rustc_middle::mir::ConstAlloc,
     rustc_middle::mir::interpret::GlobalId,
-    rustc_middle::mir::interpret::LitToConstInput,
     rustc_middle::mir::interpret::EvalStaticInitializerRawResult,
     rustc_middle::mir::mono::MonoItemPartitions,
     rustc_middle::traits::query::MethodAutoderefStepsResult,
@@ -466,6 +469,7 @@ impl_erasable_for_single_lifetime_types! {
     rustc_middle::ty::InstanceKind,
     rustc_middle::ty::layout::FnAbiError,
     rustc_middle::ty::layout::LayoutError,
+    rustc_middle::ty::LitToConstInput,
     rustc_middle::ty::ParamEnv,
     rustc_middle::ty::TypingEnv,
     rustc_middle::ty::Predicate,

compiler/rustc_middle/src/query/keys.rs

@@ -87,7 +87,7 @@ impl<'tcx> Key for (Ty<'tcx>, Option<ty::ExistentialTraitRef<'tcx>>) {
     }
 }
 
-impl<'tcx> Key for mir::interpret::LitToConstInput<'tcx> {
+impl<'tcx> Key for ty::LitToConstInput<'tcx> {
     fn default_span(&self, _tcx: TyCtxt<'_>) -> Span {
         DUMMY_SP
     }

compiler/rustc_middle/src/ty/consts.rs

@@ -11,10 +11,12 @@ use crate::ty::{self, Ty, TyCtxt};
 
 mod int;
 mod kind;
+mod lit;
 mod valtree;
 
 pub use int::*;
 pub use kind::*;
+pub use lit::*;
 use rustc_span::{DUMMY_SP, ErrorGuaranteed};
 pub use valtree::*;
 

compiler/rustc_middle/src/ty/consts/lit.rs

@@ -0,0 +1,55 @@
+use rustc_ast::LitKind;
+use rustc_hir;
+use rustc_macros::HashStable;
+
+use crate::ty::{self, Ty, TyCtxt};
+
+/// Input argument for `tcx.lit_to_const`.
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash, HashStable)]
+pub struct LitToConstInput<'tcx> {
+    /// The absolute value of the resultant constant.
+    pub lit: LitKind,
+    /// The type of the constant.
+    pub ty: Ty<'tcx>,
+    /// If the constant is negative.
+    pub neg: bool,
+}
+
+/// Checks whether a literal can be interpreted as a const of the given type.
+pub fn const_lit_matches_ty<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    kind: &LitKind,
+    ty: Ty<'tcx>,
+    neg: bool,
+) -> bool {
+    match (*kind, ty.kind()) {
+        (LitKind::Str(..), ty::Ref(_, inner_ty, _)) if inner_ty.is_str() => true,
+        (LitKind::Str(..), ty::Str) if tcx.features().deref_patterns() => true,
+        (LitKind::ByteStr(..), ty::Ref(_, inner_ty, _))
+            if let ty::Slice(ty) | ty::Array(ty, _) = inner_ty.kind()
+                && matches!(ty.kind(), ty::Uint(ty::UintTy::U8)) =>
+        {
+            true
+        }
+        (LitKind::ByteStr(..), ty::Slice(inner_ty) | ty::Array(inner_ty, _))
+            if tcx.features().deref_patterns()
+                && matches!(inner_ty.kind(), ty::Uint(ty::UintTy::U8)) =>
+        {
+            true
+        }
+        (LitKind::Byte(..), ty::Uint(ty::UintTy::U8)) => true,
+        (LitKind::CStr(..), ty::Ref(_, inner_ty, _))
+            if matches!(inner_ty.kind(), ty::Adt(def, _)
+                if tcx.is_lang_item(def.did(), rustc_hir::LangItem::CStr)) =>
+        {
+            true
+        }
+        (LitKind::Int(..), ty::Uint(_)) if !neg => true,
+        (LitKind::Int(..), ty::Int(_)) => true,
+        (LitKind::Bool(..), ty::Bool) => true,
+        (LitKind::Float(..), ty::Float(_)) => true,
+        (LitKind::Char(..), ty::Char) => true,
+        (LitKind::Err(..), _) => true,
+        _ => false,
+    }
+}

compiler/rustc_middle/src/ty/mod.rs

@@ -76,8 +76,9 @@ pub use self::closure::{
     place_to_string_for_capture,
 };
 pub use self::consts::{
-    AtomicOrdering, Const, ConstInt, ConstKind, ConstToValTreeResult, Expr, ExprKind, ScalarInt,
-    SimdAlign, UnevaluatedConst, ValTree, ValTreeKindExt, Value,
+    AtomicOrdering, Const, ConstInt, ConstKind, ConstToValTreeResult, Expr, ExprKind,
+    LitToConstInput, ScalarInt, SimdAlign, UnevaluatedConst, ValTree, ValTreeKindExt, Value,
+    const_lit_matches_ty,
 };
 pub use self::context::{
     CtxtInterners, CurrentGcx, Feed, FreeRegionInfo, GlobalCtxt, Lift, TyCtxt, TyCtxtFeed, tls,

compiler/rustc_mir_build/src/builder/expr/as_constant.rs

@@ -1,14 +1,14 @@
-//! See docs in build/expr/mod.rs
+//! See docs in builder/expr/mod.rs
 
 use rustc_abi::Size;
 use rustc_ast::{self as ast};
 use rustc_hir::LangItem;
-use rustc_middle::mir::interpret::{CTFE_ALLOC_SALT, LitToConstInput, Scalar};
+use rustc_middle::mir::interpret::{CTFE_ALLOC_SALT, Scalar};
 use rustc_middle::mir::*;
 use rustc_middle::thir::*;
 use rustc_middle::ty::{
-    self, CanonicalUserType, CanonicalUserTypeAnnotation, Ty, TyCtxt, TypeVisitableExt as _,
-    UserTypeAnnotationIndex,
+    self, CanonicalUserType, CanonicalUserTypeAnnotation, LitToConstInput, Ty, TyCtxt,
+    TypeVisitableExt as _, UserTypeAnnotationIndex,
 };
 use rustc_middle::{bug, mir, span_bug};
 use tracing::{instrument, trace};

compiler/rustc_mir_build/src/thir/constant.rs

@@ -2,20 +2,19 @@ use rustc_abi::Size;
 use rustc_ast::{self as ast, UintTy};
 use rustc_hir::LangItem;
 use rustc_middle::bug;
-use rustc_middle::mir::interpret::LitToConstInput;
-use rustc_middle::ty::{self, ScalarInt, TyCtxt, TypeVisitableExt as _};
+use rustc_middle::ty::{self, LitToConstInput, ScalarInt, Ty, TyCtxt, TypeVisitableExt as _};
 use tracing::trace;
 
 use crate::builder::parse_float_into_scalar;
 
 pub(crate) fn lit_to_const<'tcx>(
     tcx: TyCtxt<'tcx>,
     lit_input: LitToConstInput<'tcx>,
-) -> ty::Const<'tcx> {
-    let LitToConstInput { lit, ty, neg } = lit_input;
+) -> Option<ty::Value<'tcx>> {
+    let LitToConstInput { lit, ty: expected_ty, neg } = lit_input;
 
-    if let Err(guar) = ty.error_reported() {
-        return ty::Const::new_error(tcx, guar);
+    if expected_ty.error_reported().is_err() {
+        return None;
     }
 
     let trunc = |n, width: ty::UintTy| {
@@ -32,63 +31,84 @@ pub(crate) fn lit_to_const<'tcx>(
             .unwrap_or_else(|| bug!("expected to create ScalarInt from uint {:?}", result))
     };
 
-    let valtree = match (lit, ty.kind()) {
-        (ast::LitKind::Str(s, _), ty::Ref(_, inner_ty, _)) if inner_ty.is_str() => {
+    let (valtree, valtree_ty) = match (lit, expected_ty.kind()) {
+        (ast::LitKind::Str(s, _), _) => {
             let str_bytes = s.as_str().as_bytes();
-            ty::ValTree::from_raw_bytes(tcx, str_bytes)
-        }
-        (ast::LitKind::Str(s, _), ty::Str) if tcx.features().deref_patterns() => {
-            // String literal patterns may have type `str` if `deref_patterns` is enabled, in order
-            // to allow `deref!("..."): String`.
-            let str_bytes = s.as_str().as_bytes();
-            ty::ValTree::from_raw_bytes(tcx, str_bytes)
+            let valtree_ty = Ty::new_imm_ref(tcx, tcx.lifetimes.re_static, tcx.types.str_);
+            (ty::ValTree::from_raw_bytes(tcx, str_bytes), valtree_ty)
         }
         (ast::LitKind::ByteStr(byte_sym, _), ty::Ref(_, inner_ty, _))
             if let ty::Slice(ty) | ty::Array(ty, _) = inner_ty.kind()
                 && let ty::Uint(UintTy::U8) = ty.kind() =>
         {
-            ty::ValTree::from_raw_bytes(tcx, byte_sym.as_byte_str())
+            (ty::ValTree::from_raw_bytes(tcx, byte_sym.as_byte_str()), expected_ty)
         }
         (ast::LitKind::ByteStr(byte_sym, _), ty::Slice(inner_ty) | ty::Array(inner_ty, _))
             if tcx.features().deref_patterns()
                 && let ty::Uint(UintTy::U8) = inner_ty.kind() =>
         {
             // Byte string literal patterns may have type `[u8]` or `[u8; N]` if `deref_patterns` is
             // enabled, in order to allow, e.g., `deref!(b"..."): Vec<u8>`.
-            ty::ValTree::from_raw_bytes(tcx, byte_sym.as_byte_str())
+            (ty::ValTree::from_raw_bytes(tcx, byte_sym.as_byte_str()), expected_ty)
         }
-        (ast::LitKind::Byte(n), ty::Uint(ty::UintTy::U8)) => {
-            ty::ValTree::from_scalar_int(tcx, n.into())
+        (ast::LitKind::ByteStr(byte_sym, _), _) => {
+            let valtree = ty::ValTree::from_raw_bytes(tcx, byte_sym.as_byte_str());
+            let valtree_ty = Ty::new_array(tcx, tcx.types.u8, byte_sym.as_byte_str().len() as u64);
+            (valtree, valtree_ty)
         }
-        (ast::LitKind::CStr(byte_sym, _), ty::Ref(_, inner_ty, _)) if matches!(inner_ty.kind(), ty::Adt(def, _) if tcx.is_lang_item(def.did(), LangItem::CStr)) =>
+        (ast::LitKind::Byte(n), _) => (ty::ValTree::from_scalar_int(tcx, n.into()), tcx.types.u8),
+        (ast::LitKind::CStr(byte_sym, _), _)
+            if let Some(cstr_def_id) = tcx.lang_items().get(LangItem::CStr) =>
         {
             // A CStr is a newtype around a byte slice, so we create the inner slice here.
             // We need a branch for each "level" of the data structure.
+            let cstr_ty = tcx.type_of(cstr_def_id).skip_binder();
             let bytes = ty::ValTree::from_raw_bytes(tcx, byte_sym.as_byte_str());
-            ty::ValTree::from_branches(tcx, [ty::Const::new_value(tcx, bytes, *inner_ty)])
+            let valtree =
+                ty::ValTree::from_branches(tcx, [ty::Const::new_value(tcx, bytes, cstr_ty)]);
+            let valtree_ty = Ty::new_imm_ref(tcx, tcx.lifetimes.re_static, cstr_ty);
+            (valtree, valtree_ty)
         }
-        (ast::LitKind::Int(n, _), ty::Uint(ui)) if !neg => {
+        (ast::LitKind::Int(n, ast::LitIntType::Unsigned(ui)), _) if !neg => {
+            let scalar_int = trunc(n.get(), ui);
+            (ty::ValTree::from_scalar_int(tcx, scalar_int), Ty::new_uint(tcx, ui))
+        }
+        (ast::LitKind::Int(_, ast::LitIntType::Unsigned(_)), _) if neg => return None,
+        (ast::LitKind::Int(n, ast::LitIntType::Signed(i)), _) => {
+            let scalar_int =
+                trunc(if neg { u128::wrapping_neg(n.get()) } else { n.get() }, i.to_unsigned());
+            (ty::ValTree::from_scalar_int(tcx, scalar_int), Ty::new_int(tcx, i))
+        }
+        (ast::LitKind::Int(n, ast::LitIntType::Unsuffixed), ty::Uint(ui)) if !neg => {
             let scalar_int = trunc(n.get(), *ui);
-            ty::ValTree::from_scalar_int(tcx, scalar_int)
+            (ty::ValTree::from_scalar_int(tcx, scalar_int), Ty::new_uint(tcx, *ui))
         }
-        (ast::LitKind::Int(n, _), ty::Int(i)) => {
+        (ast::LitKind::Int(n, ast::LitIntType::Unsuffixed), ty::Int(i)) => {
             // Unsigned "negation" has the same bitwise effect as signed negation,
             // which gets the result we want without additional casts.
             let scalar_int =
                 trunc(if neg { u128::wrapping_neg(n.get()) } else { n.get() }, i.to_unsigned());
-            ty::ValTree::from_scalar_int(tcx, scalar_int)
+            (ty::ValTree::from_scalar_int(tcx, scalar_int), Ty::new_int(tcx, *i))
+        }
+        (ast::LitKind::Bool(b), _) => (ty::ValTree::from_scalar_int(tcx, b.into()), tcx.types.bool),
+        (ast::LitKind::Float(n, ast::LitFloatType::Suffixed(fty)), _) => {
+            let fty = match fty {
+                ast::FloatTy::F16 => ty::FloatTy::F16,
+                ast::FloatTy::F32 => ty::FloatTy::F32,
+                ast::FloatTy::F64 => ty::FloatTy::F64,
+                ast::FloatTy::F128 => ty::FloatTy::F128,
+            };
+            let bits = parse_float_into_scalar(n, fty, neg)?;
+            (ty::ValTree::from_scalar_int(tcx, bits), Ty::new_float(tcx, fty))
         }
-        (ast::LitKind::Bool(b), ty::Bool) => ty::ValTree::from_scalar_int(tcx, b.into()),
-        (ast::LitKind::Float(n, _), ty::Float(fty)) => {
-            let bits = parse_float_into_scalar(n, *fty, neg).unwrap_or_else(|| {
-                tcx.dcx().bug(format!("couldn't parse float literal: {:?}", lit_input.lit))
-            });
-            ty::ValTree::from_scalar_int(tcx, bits)
+        (ast::LitKind::Float(n, ast::LitFloatType::Unsuffixed), ty::Float(fty)) => {
+            let bits = parse_float_into_scalar(n, *fty, neg)?;
+            (ty::ValTree::from_scalar_int(tcx, bits), Ty::new_float(tcx, *fty))
         }
-        (ast::LitKind::Char(c), ty::Char) => ty::ValTree::from_scalar_int(tcx, c.into()),
-        (ast::LitKind::Err(guar), _) => return ty::Const::new_error(tcx, guar),
-        _ => return ty::Const::new_misc_error(tcx),
+        (ast::LitKind::Char(c), _) => (ty::ValTree::from_scalar_int(tcx, c.into()), tcx.types.char),
+        (ast::LitKind::Err(_), _) => return None,
+        _ => return None,
     };
 
-    ty::Const::new_value(tcx, valtree, ty)
+    Some(ty::Value { ty: valtree_ty, valtree })
 }