use AllocId and Ty in ExprKind::StaticRef and delay ConstValue construction

Author: b-naber

compiler/rustc_middle/src/thir.rs

@@ -17,6 +17,7 @@ use rustc_index::newtype_index;
 use rustc_index::vec::IndexVec;
 use rustc_middle::infer::canonical::Canonical;
 use rustc_middle::middle::region;
+use rustc_middle::mir::interpret::AllocId;
 use rustc_middle::mir::{
     BinOp, BorrowKind, FakeReadCause, Field, Mutability, UnOp, UserTypeProjection,
 };
@@ -419,7 +420,8 @@ pub enum ExprKind<'tcx> {
     /// This is only distinguished from `Literal` so that we can register some
     /// info for diagnostics.
     StaticRef {
-        literal: Const<'tcx>,
+        alloc_id: AllocId,
+        ty: Ty<'tcx>,
         def_id: DefId,
     },
     /// Inline assembly, i.e. `asm!()`.
@@ -715,7 +717,11 @@ impl<'tcx> fmt::Display for Pat<'tcx> {
                         Some(&adt_def.variants[variant_index])
                     }
                     _ => self.ty.ty_adt_def().and_then(|adt| {
-                        if !adt.is_enum() { Some(adt.non_enum_variant()) } else { None }
+                        if !adt.is_enum() {
+                            Some(adt.non_enum_variant())
+                        } else {
+                            None
+                        }
                     }),
                 };
 

compiler/rustc_middle/src/thir/visit.rs

@@ -123,7 +123,7 @@ pub fn walk_expr<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, expr: &Exp
         }
         Closure { closure_id: _, substs: _, upvars: _, movability: _, fake_reads: _ } => {}
         Literal { literal, user_ty: _, const_id: _ } => visitor.visit_const(literal),
-        StaticRef { literal, def_id: _ } => visitor.visit_const(literal),
+        StaticRef { .. } => {}
         InlineAsm { ref operands, template: _, options: _, line_spans: _ } => {
             for op in &**operands {
                 use InlineAsmOperand::*;

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

@@ -1,6 +1,7 @@
 //! See docs in build/expr/mod.rs
 
 use crate::build::Builder;
+use rustc_middle::mir::interpret::{ConstValue, Scalar};
 use rustc_middle::mir::*;
 use rustc_middle::thir::*;
 use rustc_middle::ty::CanonicalUserTypeAnnotation;
@@ -26,11 +27,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 assert_eq!(literal.ty(), ty);
                 Constant { span, user_ty, literal: literal.into() }
             }
-            ExprKind::StaticRef { literal, .. } => {
-                let const_val = literal.val.try_to_value().unwrap_or_else(|| {
-                    bug!("expected `ConstKind::Value`, but found {:?}", literal.val)
-                });
-                let literal = ConstantKind::Val(const_val, literal.ty);
+            ExprKind::StaticRef { alloc_id, ty, .. } => {
+                let const_val =
+                    ConstValue::Scalar(Scalar::from_pointer(alloc_id.into(), &this.tcx));
+                let literal = ConstantKind::Val(const_val, ty);
 
                 Constant { span, user_ty: None, literal }
             }

compiler/rustc_mir_build/src/thir/cx/expr.rs

@@ -8,7 +8,6 @@ use rustc_middle::hir::place::Place as HirPlace;
 use rustc_middle::hir::place::PlaceBase as HirPlaceBase;
 use rustc_middle::hir::place::ProjectionKind as HirProjectionKind;
 use rustc_middle::middle::region;
-use rustc_middle::mir::interpret::Scalar;
 use rustc_middle::mir::{BinOp, BorrowKind, Field, UnOp};
 use rustc_middle::thir::*;
 use rustc_middle::ty::adjustment::{
@@ -943,15 +942,8 @@ impl<'tcx> Cx<'tcx> {
                 let kind = if self.tcx.is_thread_local_static(id) {
                     ExprKind::ThreadLocalRef(id)
                 } else {
-                    let ptr = self.tcx.create_static_alloc(id);
-                    ExprKind::StaticRef {
-                        literal: ty::Const::from_scalar(
-                            self.tcx,
-                            Scalar::from_pointer(ptr.into(), &self.tcx),
-                            ty,
-                        ),
-                        def_id: id,
-                    }
+                    let alloc_id = self.tcx.create_static_alloc(id);
+                    ExprKind::StaticRef { alloc_id, ty, def_id: id }
                 };
                 ExprKind::Deref {
                     arg: self.thir.exprs.push(Expr { ty, temp_lifetime, span: expr.span, kind }),