Rollup merge of #104235 - compiler-errors:more-ct-guar, r=oli-obk

Use `const_error_with_guaranteed` more

Better to pass down an ErrorGuaranteed rather than making a new one out of thin air, for some usages. Also for the ones where we *do* need to delay a bug, that delayed bug will have a more descriptive message.

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

@@ -106,6 +106,7 @@ macro_rules! throw_machine_stop {
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::{HashMapExt, Lock};
 use rustc_data_structures::tiny_list::TinyList;
+use rustc_errors::ErrorGuaranteed;
 use rustc_hir::def_id::DefId;
 use rustc_macros::HashStable;
 use rustc_middle::ty::print::with_no_trimmed_paths;
@@ -176,7 +177,7 @@ pub enum LitToConstError {
     /// This is used for graceful error handling (`delay_span_bug`) in
     /// type checking (`Const::from_anon_const`).
     TypeError,
-    Reported,
+    Reported(ErrorGuaranteed),
 }
 
 #[derive(Copy, Clone, Eq, Hash, Ord, PartialEq, PartialOrd)]

compiler/rustc_middle/src/mir/mod.rs

@@ -2251,7 +2251,9 @@ pub fn eval(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> Self {
                 match tcx.const_eval_resolve(param_env, uneval, None) {
                     Ok(val) => Self::Val(val, ty),
                     Err(ErrorHandled::TooGeneric | ErrorHandled::Linted) => self,
-                    Err(_) => Self::Ty(tcx.const_error(ty)),
+                    Err(ErrorHandled::Reported(guar)) => {
+                        Self::Ty(tcx.const_error_with_guaranteed(ty, guar))
+                    }
                 }
             }
         }

compiler/rustc_middle/src/ty/consts.rs

@@ -2,7 +2,6 @@
 use crate::mir::ConstantKind;
 use crate::ty::{self, InternalSubsts, ParamEnv, ParamEnvAnd, Ty, TyCtxt};
 use rustc_data_structures::intern::Interned;
-use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_macros::HashStable;
@@ -225,7 +224,7 @@ pub fn eval(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Const<'tcx> {
         if let Some(val) = self.kind().try_eval_for_typeck(tcx, param_env) {
             match val {
                 Ok(val) => Const::from_value(tcx, val, self.ty()),
-                Err(ErrorGuaranteed { .. }) => tcx.const_error(self.ty()),
+                Err(guar) => tcx.const_error_with_guaranteed(self.ty(), guar),
             }
         } else {
             // Either the constant isn't evaluatable or ValTree creation failed.
@@ -240,7 +239,7 @@ pub fn eval_for_mir(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Const
         if let Some(val) = self.kind().try_eval_for_mir(tcx, param_env) {
             match val {
                 Ok(const_val) => ConstantKind::from_value(const_val, self.ty()),
-                Err(ErrorGuaranteed { .. }) => ConstantKind::Ty(tcx.const_error(self.ty())),
+                Err(guar) => ConstantKind::Ty(tcx.const_error_with_guaranteed(self.ty(), guar)),
             }
         } else {
             ConstantKind::Ty(self)

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

@@ -9,6 +9,7 @@
 use rustc_middle::mir::*;
 use rustc_middle::thir::*;
 use rustc_middle::ty::{self, CanonicalUserTypeAnnotation, TyCtxt};
+use rustc_span::DUMMY_SP;
 use rustc_target::abi::Size;
 
 impl<'a, 'tcx> Builder<'a, 'tcx> {
@@ -26,7 +27,9 @@ pub(crate) fn as_constant(&mut self, expr: &Expr<'tcx>) -> Constant<'tcx> {
                 let literal =
                     match lit_to_mir_constant(tcx, LitToConstInput { lit: &lit.node, ty, neg }) {
                         Ok(c) => c,
-                        Err(LitToConstError::Reported) => ConstantKind::Ty(tcx.const_error(ty)),
+                        Err(LitToConstError::Reported(guar)) => {
+                            ConstantKind::Ty(tcx.const_error_with_guaranteed(ty, guar))
+                        }
                         Err(LitToConstError::TypeError) => {
                             bug!("encountered type error in `lit_to_mir_constant")
                         }
@@ -105,7 +108,15 @@ pub(crate) fn lit_to_mir_constant<'tcx>(
     let LitToConstInput { lit, ty, neg } = lit_input;
     let trunc = |n| {
         let param_ty = ty::ParamEnv::reveal_all().and(ty);
-        let width = tcx.layout_of(param_ty).map_err(|_| LitToConstError::Reported)?.size;
+        let width = tcx
+            .layout_of(param_ty)
+            .map_err(|_| {
+                LitToConstError::Reported(tcx.sess.delay_span_bug(
+                    DUMMY_SP,
+                    format!("couldn't compute width of literal: {:?}", lit_input.lit),
+                ))
+            })?
+            .size;
         trace!("trunc {} with size {} and shift {}", n, width.bits(), 128 - width.bits());
         let result = width.truncate(n);
         trace!("trunc result: {}", result);
@@ -136,12 +147,20 @@ pub(crate) fn lit_to_mir_constant<'tcx>(
         (ast::LitKind::Int(n, _), ty::Uint(_)) | (ast::LitKind::Int(n, _), ty::Int(_)) => {
             trunc(if neg { (*n as i128).overflowing_neg().0 as u128 } else { *n })?
         }
-        (ast::LitKind::Float(n, _), ty::Float(fty)) => {
-            parse_float_into_constval(*n, *fty, neg).ok_or(LitToConstError::Reported)?
-        }
+        (ast::LitKind::Float(n, _), ty::Float(fty)) => parse_float_into_constval(*n, *fty, neg)
+            .ok_or_else(|| {
+                LitToConstError::Reported(tcx.sess.delay_span_bug(
+                    DUMMY_SP,
+                    format!("couldn't parse float literal: {:?}", lit_input.lit),
+                ))
+            })?,
         (ast::LitKind::Bool(b), ty::Bool) => ConstValue::Scalar(Scalar::from_bool(*b)),
         (ast::LitKind::Char(c), ty::Char) => ConstValue::Scalar(Scalar::from_char(*c)),
-        (ast::LitKind::Err, _) => return Err(LitToConstError::Reported),
+        (ast::LitKind::Err, _) => {
+            return Err(LitToConstError::Reported(
+                tcx.sess.delay_span_bug(DUMMY_SP, "encountered LitKind::Err during mir build"),
+            ));
+        }
         _ => return Err(LitToConstError::TypeError),
     };
 

compiler/rustc_mir_build/src/thir/constant.rs

@@ -1,6 +1,7 @@
 use rustc_ast as ast;
 use rustc_middle::mir::interpret::{LitToConstError, LitToConstInput};
 use rustc_middle::ty::{self, ParamEnv, ScalarInt, TyCtxt};
+use rustc_span::DUMMY_SP;
 
 pub(crate) fn lit_to_const<'tcx>(
     tcx: TyCtxt<'tcx>,
@@ -10,7 +11,15 @@ pub(crate) fn lit_to_const<'tcx>(
 
     let trunc = |n| {
         let param_ty = ParamEnv::reveal_all().and(ty);
-        let width = tcx.layout_of(param_ty).map_err(|_| LitToConstError::Reported)?.size;
+        let width = tcx
+            .layout_of(param_ty)
+            .map_err(|_| {
+                LitToConstError::Reported(tcx.sess.delay_span_bug(
+                    DUMMY_SP,
+                    format!("couldn't compute width of literal: {:?}", lit_input.lit),
+                ))
+            })?
+            .size;
         trace!("trunc {} with size {} and shift {}", n, width.bits(), 128 - width.bits());
         let result = width.truncate(n);
         trace!("trunc result: {}", result);
@@ -44,7 +53,11 @@ pub(crate) fn lit_to_const<'tcx>(
         }
         (ast::LitKind::Bool(b), ty::Bool) => ty::ValTree::from_scalar_int((*b).into()),
         (ast::LitKind::Char(c), ty::Char) => ty::ValTree::from_scalar_int((*c).into()),
-        (ast::LitKind::Err, _) => return Err(LitToConstError::Reported),
+        (ast::LitKind::Err, _) => {
+            return Err(LitToConstError::Reported(
+                tcx.sess.delay_span_bug(DUMMY_SP, "encountered LitKind::Err during mir build"),
+            ));
+        }
         _ => return Err(LitToConstError::TypeError),
     };
 

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

@@ -614,7 +614,7 @@ fn lower_lit(&mut self, expr: &'tcx hir::Expr<'tcx>) -> PatKind<'tcx> {
             LitToConstInput { lit: &lit.node, ty: self.typeck_results.expr_ty(expr), neg };
         match self.tcx.at(expr.span).lit_to_mir_constant(lit_input) {
             Ok(constant) => self.const_to_pat(constant, expr.hir_id, lit.span, false).kind,
-            Err(LitToConstError::Reported) => PatKind::Wild,
+            Err(LitToConstError::Reported(_)) => PatKind::Wild,
             Err(LitToConstError::TypeError) => bug!("lower_lit: had type error"),
         }
     }

compiler/rustc_ty_utils/src/consts.rs

@@ -235,7 +235,9 @@ fn recurse_build(&mut self, node: thir::ExprId) -> Result<NodeId, ErrorGuarantee
                     neg,
                 }) {
                     Ok(c) => c,
-                    Err(LitToConstError::Reported) => self.tcx.const_error(node.ty),
+                    Err(LitToConstError::Reported(guar)) => {
+                        self.tcx.const_error_with_guaranteed(node.ty, guar)
+                    }
                     Err(LitToConstError::TypeError) => {
                         bug!("encountered type error in lit_to_const")
                     }