From 4e1eeb9a4543c9c1bfbbac0b7813520c5b0be5ef Mon Sep 17 00:00:00 2001
From: clemencetbk <kohclemence@gmail.com>
Date: Sat, 16 Nov 2019 12:04:17 -0500
Subject: [PATCH 1/2] Add explanation message for E0641

---
 src/librustc_error_codes/error_codes.rs       |  2 +-
 src/librustc_error_codes/error_codes/E0641.md | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 src/librustc_error_codes/error_codes/E0641.md

diff --git a/src/librustc_error_codes/error_codes.rs b/src/librustc_error_codes/error_codes.rs
index ffefe51f854f5..f886d06b96d1b 100644
--- a/src/librustc_error_codes/error_codes.rs
+++ b/src/librustc_error_codes/error_codes.rs
@@ -351,6 +351,7 @@ E0635: include_str!("./error_codes/E0635.md"),
 E0636: include_str!("./error_codes/E0636.md"),
 E0638: include_str!("./error_codes/E0638.md"),
 E0639: include_str!("./error_codes/E0639.md"),
+E0641: include_str!("./error_codes/E0641.md"),
 E0642: include_str!("./error_codes/E0642.md"),
 E0643: include_str!("./error_codes/E0643.md"),
 E0644: include_str!("./error_codes/E0644.md"),
@@ -585,7 +586,6 @@ E0744: include_str!("./error_codes/E0744.md"),
     E0634, // type has conflicting packed representaton hints
     E0637, // "'_" is not a valid lifetime bound
     E0640, // infer outlives requirements
-    E0641, // cannot cast to/from a pointer with an unknown kind
 //  E0645, // trait aliases not finished
     E0657, // `impl Trait` can only capture lifetimes bound at the fn level
     E0667, // `impl Trait` in projections
diff --git a/src/librustc_error_codes/error_codes/E0641.md b/src/librustc_error_codes/error_codes/E0641.md
new file mode 100644
index 0000000000000..e39bebce1fea6
--- /dev/null
+++ b/src/librustc_error_codes/error_codes/E0641.md
@@ -0,0 +1,19 @@
+Attempted to cast to/from a pointer with an unknown kind.
+
+Erroneous code examples:
+
+```compile_fail,E0641
+let b = 0 as *const _; // error
+```
+
+Must give information for type of pointer that is being cast from/to if the
+type cannot be inferred.
+
+```
+// Creating a pointer from reference: type can be inferred
+let a = &(String::from("Hello world!")) as *const _; // Ok
+
+let b = 0 as *const i32; // Ok
+
+let c: *const i32 = 0 as *const _; // Ok
+```
\ No newline at end of file

From dc137dd868daaa2d7821997e6a87d49fbb9e4ca8 Mon Sep 17 00:00:00 2001
From: clemencetbk <kohclemence@gmail.com>
Date: Sat, 16 Nov 2019 12:05:26 -0500
Subject: [PATCH 2/2] Update ui tests

---
 src/test/ui/issues/issue-45730.stderr             | 1 +
 src/test/ui/order-dependent-cast-inference.stderr | 1 +
 2 files changed, 2 insertions(+)

diff --git a/src/test/ui/issues/issue-45730.stderr b/src/test/ui/issues/issue-45730.stderr
index 4fc1e3835f7ad..3c400d6eefaa8 100644
--- a/src/test/ui/issues/issue-45730.stderr
+++ b/src/test/ui/issues/issue-45730.stderr
@@ -30,3 +30,4 @@ LL |     let x = 0 as *const i32 as *const _ as *mut _;
 
 error: aborting due to 3 previous errors
 
+For more information about this error, try `rustc --explain E0641`.
diff --git a/src/test/ui/order-dependent-cast-inference.stderr b/src/test/ui/order-dependent-cast-inference.stderr
index 01e59f8f022fd..081038c573acf 100644
--- a/src/test/ui/order-dependent-cast-inference.stderr
+++ b/src/test/ui/order-dependent-cast-inference.stderr
@@ -10,3 +10,4 @@ LL |     let mut y = 0 as *const _;
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0641`.