add special case for typeof fallback

Author: yaahc

compiler/rustc_typeck/src/check/mod.rs

@@ -540,6 +540,12 @@ fn typeck_with_fallback<'tcx>(
                             kind: TypeVariableOriginKind::TypeInference,
                             span,
                         }),
+                        Node::Ty(&hir::Ty {
+                            kind: hir::TyKind::Typeof(ref anon_const), ..
+                        }) if anon_const.hir_id == id => fcx.next_ty_var(TypeVariableOrigin {
+                            kind: TypeVariableOriginKind::TypeInference,
+                            span,
+                        }),
                         Node::Expr(&hir::Expr { kind: hir::ExprKind::InlineAsm(ia), .. })
                             if ia.operands.iter().any(|(op, _op_sp)| match op {
                                 hir::InlineAsmOperand::Const { anon_const } => {