remove a dead parameter that everyone sets to None

Author: RalfJung

src/librustc_mir/const_eval/error.rs

@@ -55,6 +55,6 @@ pub fn error_to_const_error<'mir, 'tcx, M: Machine<'mir, 'tcx>>(
     mut error: InterpErrorInfo<'tcx>,
 ) -> ConstEvalErr<'tcx> {
     error.print_backtrace();
-    let stacktrace = ecx.generate_stacktrace(None);
+    let stacktrace = ecx.generate_stacktrace();
     ConstEvalErr { error: error.kind, stacktrace, span: ecx.tcx.span }
 }

src/librustc_mir/interpret/eval_context.rs

@@ -17,7 +17,7 @@ use rustc_middle::ty::layout::{self, Align, HasDataLayout, LayoutOf, Size, TyAnd
 use rustc_middle::ty::query::TyCtxtAt;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable};
-use rustc_span::source_map::{Span, DUMMY_SP};
+use rustc_span::source_map::DUMMY_SP;
 
 use super::{
     Immediate, MPlaceTy, Machine, MemPlace, MemPlaceMeta, Memory, OpTy, Operand, Place, PlaceTy,
@@ -853,7 +853,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         }
     }
 
-    pub fn generate_stacktrace(&self, explicit_span: Option<Span>) -> Vec<FrameInfo<'tcx>> {
+    pub fn generate_stacktrace(&self) -> Vec<FrameInfo<'tcx>> {
         let mut frames = Vec::new();
         for frame in self.stack().iter().rev() {
             let source_info = frame.current_source_info();
@@ -867,7 +867,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
             frames.push(FrameInfo { span, instance: frame.instance, lint_root });
         }
-        trace!("generate stacktrace: {:#?}, {:?}", frames, explicit_span);
+        trace!("generate stacktrace: {:#?}", frames);
         frames
     }
 }