Auto merge of #61361 - estebank:infer-type, r=varkor

[rust.git] / src / librustc / ty / print / pretty.rs

diff --git a/src/librustc/ty/print/pretty.rs b/src/librustc/ty/print/pretty.rs
index a8a6bca4fd434f8e7c838550b050bf8ac43988c7..513ffd69ccaadfc58309b79de33da5cb3ec21e16 100644 (file)
--- a/src/librustc/ty/print/pretty.rs
+++ b/src/librustc/ty/print/pretty.rs
@@ -483,7 +483,17 @@ fn pretty_print_type(
             ty::FnPtr(ref bare_fn) => {
                 p!(print(bare_fn))
             }
-            ty::Infer(infer_ty) => p!(write("{}", infer_ty)),
+            ty::Infer(infer_ty) => {
+                if let ty::TyVar(ty_vid) = infer_ty {
+                    if let Some(name) = self.infer_ty_name(ty_vid) {
+                        p!(write("{}", name))
+                    } else {
+                        p!(write("{}", infer_ty))
+                    }
+                } else {
+                    p!(write("{}", infer_ty))
+                }
+            },
             ty::Error => p!(write("[type error]")),
             ty::Param(ref param_ty) => p!(write("{}", param_ty)),
             ty::Bound(debruijn, bound_ty) => {
@@ -681,6 +691,10 @@ fn pretty_print_type(
         Ok(self)
     }
 
+    fn infer_ty_name(&self, _: ty::TyVid) -> Option<String> {
+        None
+    }
+
     fn pretty_print_dyn_existential(
         mut self,
         predicates: &'tcx ty::List<ty::ExistentialPredicate<'tcx>>,
@@ -931,6 +945,8 @@ pub struct FmtPrinterData<'a, 'gcx, 'tcx, F> {
     binder_depth: usize,
 
     pub region_highlight_mode: RegionHighlightMode,
+
+    pub name_resolver: Option<Box<&'a dyn Fn(ty::sty::TyVid) -> Option<String>>>,
 }
 
 impl<F> Deref for FmtPrinter<'a, 'gcx, 'tcx, F> {
@@ -957,6 +973,7 @@ pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>, fmt: F, ns: Namespace) -> Self {
             region_index: 0,
             binder_depth: 0,
             region_highlight_mode: RegionHighlightMode::default(),
+            name_resolver: None,
         }))
     }
 }
@@ -1206,6 +1223,10 @@ fn path_generic_args(
 }
 
 impl<F: fmt::Write> PrettyPrinter<'gcx, 'tcx> for FmtPrinter<'_, 'gcx, 'tcx, F> {
+    fn infer_ty_name(&self, id: ty::TyVid) -> Option<String> {
+        self.0.name_resolver.as_ref().and_then(|func| func(id))
+    }
+
     fn print_value_path(
         mut self,
         def_id: DefId,