Always format to internal String in FmtPrinter

This avoids monomorphizing for different parameters, decreasing generic code
instantiated downstream from rustc_middle.

1 files changed, 5 insertions, 5 deletions

diff --git a/compiler/rustc_const_eval/src/interpret/operand.rs b/compiler/rustc_const_eval/src/interpret/operand.rs
index ec5eafcd633..55f3914769d 100644
--- a/compiler/rustc_const_eval/src/interpret/operand.rs
+++ b/compiler/rustc_const_eval/src/interpret/operand.rs
@@ -109,11 +109,11 @@ rustc_data_structures::static_assert_size!(ImmTy<'_>, 72);
 impl<Tag: Provenance> std::fmt::Display for ImmTy<'_, Tag> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         /// Helper function for printing a scalar to a FmtPrinter
-        fn p<'a, 'tcx, F: std::fmt::Write, Tag: Provenance>(
-            cx: FmtPrinter<'a, 'tcx, F>,
+        fn p<'a, 'tcx, Tag: Provenance>(
+            cx: FmtPrinter<'a, 'tcx>,
             s: ScalarMaybeUninit<Tag>,
             ty: Ty<'tcx>,
-        ) -> Result<FmtPrinter<'a, 'tcx, F>, std::fmt::Error> {
+        ) -> Result<FmtPrinter<'a, 'tcx>, std::fmt::Error> {
             match s {
                 ScalarMaybeUninit::Scalar(Scalar::Int(int)) => {
                     cx.pretty_print_const_scalar_int(int, ty, true)
@@ -138,8 +138,8 @@ impl<Tag: Provenance> std::fmt::Display for ImmTy<'_, Tag> {
             match self.imm {
                 Immediate::Scalar(s) => {
                     if let Some(ty) = tcx.lift(self.layout.ty) {
-                        let cx = FmtPrinter::new(tcx, f, Namespace::ValueNS);
-                        p(cx, s, ty)?;
+                        let cx = FmtPrinter::new(tcx, Namespace::ValueNS);
+                        f.write_str(&p(cx, s, ty)?.into_buffer())?;
                         return Ok(());
                     }
                     write!(f, "{}: {}", s, self.layout.ty)