Add inferred args to typeck

compiler/rustc_typeck/src/astconv/generics.rs

@@ -18,23 +18,6 @@ use rustc_session::lint::builtin::LATE_BOUND_LIFETIME_ARGUMENTS;
 use rustc_span::{symbol::kw, MultiSpan, Span};
 use smallvec::SmallVec;
 
-/*
-pub fn generic_arg_for_infer_arg<'tcx>(tcx: TyCtxt<'tcx>, did: LocalDefId) -> GenericArg<'tcx> {
-    todo!()
-    let hir_id = tcx.hir().local_def_id_to_hir_id(did);
-    let arg = match tcx.hir().get(hir_id) {
-        hir::Node::GenericParam(hir::GenericParam {
-            kind: hir::GenericParamKind::Const { ty: _, default: _ },
-            ..
-        }) => todo!(),
-        _ => bug!("Expected GenericParam for generic_arg_for_infer_arg"),
-    };
-
-    assert!(!matches!(arg, GenericArg::Infer(_)));
-    arg
-}
-*/
-
 impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
     /// Report an error that a generic argument did not match the generic parameter that was
     /// expected.

compiler/rustc_typeck/src/astconv/mod.rs

@@ -479,6 +479,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                                 param.def_id,
                                 Some(arg.id()),
                                 arg.span(),
+                                None,
                                 |_, _| {
                                     // Default generic parameters may not be marked
                                     // with stability attributes, i.e. when the

compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs

@@ -581,6 +581,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    pub fn node_ty_opt(&self, id: hir::HirId) -> Option<Ty<'tcx>> {
+        match self.typeck_results.borrow().node_types().get(id) {
+            Some(&t) => Some(t),
+            None if self.is_tainted_by_errors() => Some(self.tcx.ty_error()),
+            None => None,
+        }
+    }
+
     /// Registers an obligation for checking later, during regionck, that `arg` is well-formed.
     pub fn register_wf_obligation(
         &self,

compiler/rustc_typeck/src/check/writeback.rs

@@ -331,6 +331,15 @@ impl<'cx, 'tcx> Visitor<'tcx> for WritebackCx<'cx, 'tcx> {
         let ty = self.resolve(ty, &hir_ty.span);
         self.write_ty_to_typeck_results(hir_ty.hir_id, ty);
     }
+
+    fn visit_infer(&mut self, inf: &'tcx hir::InferArg) {
+        intravisit::walk_inf(self, inf);
+        // Ignore cases where the inference is a const.
+        if let Some(ty) = self.fcx.node_ty_opt(inf.hir_id) {
+            let ty = self.resolve(ty, &inf.span);
+            self.write_ty_to_typeck_results(inf.hir_id, ty);
+        }
+    }
 }
 
 impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {

compiler/rustc_typeck/src/collect.rs

@@ -133,6 +133,7 @@ impl<'v> Visitor<'v> for PlaceholderHirTyCollector {
         match generic_arg {
             hir::GenericArg::Infer(inf) => {
                 self.0.push(inf.span);
+                intravisit::walk_inf(self, inf);
             }
             hir::GenericArg::Type(t) => self.visit_ty(t),
             _ => {}