From 68b38c3bd902deccd31d59f45d5b49e58aa76a9d Mon Sep 17 00:00:00 2001
From: Donough Liu <ldm2993593805@163.com>
Date: Fri, 10 Apr 2020 18:14:55 +0800
Subject: [PATCH 1/2] Normalize function signature in function casting check

---
 src/librustc_typeck/check/cast.rs |  5 ++++-
 src/test/ui/issues/issue-54094.rs | 14 ++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 src/test/ui/issues/issue-54094.rs

diff --git a/src/librustc_typeck/check/cast.rs b/src/librustc_typeck/check/cast.rs
index 5de0184f2bba9..38d0c42e1588b 100644
--- a/src/librustc_typeck/check/cast.rs
+++ b/src/librustc_typeck/check/cast.rs
@@ -536,7 +536,10 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                 match self.expr_ty.kind {
                     ty::FnDef(..) => {
                         // Attempt a coercion to a fn pointer type.
-                        let f = self.expr_ty.fn_sig(fcx.tcx);
+                        let f = fcx.normalize_associated_types_in(
+                            self.expr.span,
+                            &self.expr_ty.fn_sig(fcx.tcx),
+                        );
                         let res = fcx.try_coerce(
                             self.expr,
                             self.expr_ty,
diff --git a/src/test/ui/issues/issue-54094.rs b/src/test/ui/issues/issue-54094.rs
new file mode 100644
index 0000000000000..57384825a35fe
--- /dev/null
+++ b/src/test/ui/issues/issue-54094.rs
@@ -0,0 +1,14 @@
+// check-pass
+trait Zoo {
+    type X;
+}
+
+impl Zoo for u16 {
+    type X = usize;
+}
+
+fn foo(abc: <u16 as Zoo>::X) {}
+
+fn main() {
+    let x: *const u8 = foo as _;
+}
\ No newline at end of file

From 75cc40335c5ca83ffa636ea6ff249d1934223b8b Mon Sep 17 00:00:00 2001
From: Donough Liu <ldm2993593805@163.com>
Date: Fri, 10 Apr 2020 18:51:27 +0800
Subject: [PATCH 2/2] Tidy fix

---
 src/test/ui/issues/issue-54094.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/test/ui/issues/issue-54094.rs b/src/test/ui/issues/issue-54094.rs
index 57384825a35fe..ec38dc40e610a 100644
--- a/src/test/ui/issues/issue-54094.rs
+++ b/src/test/ui/issues/issue-54094.rs
@@ -11,4 +11,4 @@ fn foo(abc: <u16 as Zoo>::X) {}
 
 fn main() {
     let x: *const u8 = foo as _;
-}
\ No newline at end of file
+}