Add InterpErrorExt::to_string

Author: victor-timofei

compiler/rustc_const_eval/src/const_eval/error.rs

@@ -165,7 +165,7 @@ where
             let span = span.unwrap_or(our_span);
 
             let handler = &tcx.sess.parse_sess.span_diagnostic;
-            let mut err = handler.create_err(Spanned { span, node: InterpErrorExt(error)});
+            let mut err = handler.create_err(Spanned { span, node: InterpErrorExt(error) });
 
             for frame in frames {
                 err.eager_subdiagnostic(handler, frame);

compiler/rustc_const_eval/src/errors.rs

@@ -9,7 +9,7 @@ use rustc_middle::mir::interpret::{
     MachineStopType, PointerKind, ResourceExhaustionInfo, UndefinedBehaviorInfo, UnsupportedOpInfo,
     ValidationErrorInfo,
 };
-use rustc_middle::ty::Ty;
+use rustc_middle::ty::{self, Ty};
 use rustc_span::{ErrorGuaranteed, Span};
 use rustc_target::abi::call::AdjustForForeignAbiError;
 use rustc_target::abi::{Size, WrappingRange};
@@ -957,6 +957,25 @@ impl IntoDiagnostic<'_> for InterpErrorExt<'_> {
     }
 }
 
+impl InterpErrorExt<'_> {
+    /// Translate InterpError to String.
+    ///
+    /// This should not be used for any user-facing diagnostics,
+    /// only for debug messages in the docs.
+    pub fn to_string(self) -> String {
+        ty::tls::with(move |tcx| {
+            let handler = &tcx.sess.parse_sess.span_diagnostic;
+            let builder = self.into_diagnostic(handler);
+            let s = handler.eagerly_translate_to_string(
+                builder.message.first().unwrap().0.to_owned(),
+                builder.args(),
+            );
+            builder.cancel();
+            s
+        })
+    }
+}
+
 pub struct MachineStopExt(Box<dyn MachineStopType>);
 
 impl IntoDiagnostic<'_> for MachineStopExt {

compiler/rustc_mir_transform/src/const_prop.rs

@@ -6,7 +6,6 @@ use either::Right;
 use rustc_const_eval::const_eval::CheckAlignment;
 use rustc_const_eval::InterpErrorExt;
 use rustc_data_structures::fx::FxHashSet;
-use rustc_errors::{DiagnosticMessage, IntoDiagnostic};
 use rustc_hir::def::DefKind;
 use rustc_index::bit_set::BitSet;
 use rustc_index::{IndexSlice, IndexVec};
@@ -17,7 +16,6 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::layout::{LayoutError, LayoutOf, LayoutOfHelpers, TyAndLayout};
 use rustc_middle::ty::InternalSubsts;
 use rustc_middle::ty::{self, ConstKind, Instance, ParamEnv, Ty, TyCtxt, TypeVisitableExt};
-use rustc_span::sym::DiagnosticMessage;
 use rustc_span::{def_id::DefId, Span, DUMMY_SP};
 use rustc_target::abi::{self, Align, HasDataLayout, Size, TargetDataLayout};
 use rustc_target::spec::abi::Abi as CallAbi;
@@ -388,17 +386,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
                 op
             }
             Err(e) => {
-                let msg = ty::tls::with(move |tcx| {
-                    let handler = &tcx.sess.parse_sess.span_diagnostic;
-                    let err = InterpErrorExt(e.into_kind());
-                    let builder = err.into_diagnostic(handler);
-                    builder.cancel();
-                    "Should be diagnostic message"
-                });
-                trace!(
-                    "get_const failed: {:?}",
-                    todo!("find a way to convert diagnostic builder to string")
-                );
+                trace!("get_const failed: {}", InterpErrorExt(e.into_kind()).to_string());
                 return None;
             }
         };

compiler/rustc_mir_transform/src/const_prop_lint.rs

@@ -9,6 +9,7 @@ use rustc_const_eval::interpret::Immediate;
 use rustc_const_eval::interpret::{
     self, InterpCx, InterpResult, LocalValue, MemoryKind, OpTy, Scalar, StackPopCleanup,
 };
+use rustc_const_eval::InterpErrorExt;
 use rustc_hir::def::DefKind;
 use rustc_hir::HirId;
 use rustc_index::bit_set::BitSet;
@@ -232,10 +233,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
                 op
             }
             Err(e) => {
-                trace!(
-                    "get_const failed: {:?}",
-                    todo!("find a way to convert diagnostic to string")
-                );
+                trace!("get_const failed: {}", InterpErrorExt(e.into_kind()).to_string());
                 return None;
             }
         };

src/tools/miri/src/diagnostics.rs

@@ -3,6 +3,7 @@ use std::num::NonZeroU64;
 
 use log::trace;
 
+use rustc_const_eval::InterpErrorExt;
 use rustc_errors::DiagnosticMessage;
 use rustc_span::{source_map::DUMMY_SP, SpanData, Symbol};
 use rustc_target::abi::{Align, Size};
@@ -334,15 +335,7 @@ pub fn report_error<'tcx, 'mir>(
 
     // FIXME(fee1-dead), HACK: we want to use the error as title therefore we can just extract the
     // label and arguments from the InterpError.
-    let e = {
-        let handler = &ecx.tcx.sess.parse_sess.span_diagnostic;
-        let mut diag = ecx.tcx.sess.struct_allow("");
-        let msg = e.diagnostic_message();
-        e.add_args(handler, &mut diag);
-        let s = handler.eagerly_translate_to_string(msg, diag.args());
-        diag.cancel();
-        s
-    };
+    let e = InterpErrorExt(e).to_string();
 
     msg.insert(0, e);