From 467c93255f5abd4d6c9cb500b45ff4e9b67ea5fc Mon Sep 17 00:00:00 2001
From: Mushroom <mushroom@watchingyour.tv>
Date: Wed, 23 Dec 2020 17:44:20 +0000
Subject: [PATCH] rust: ship 1.49.0-beta on ARM

Closes #67535
---
 Formula/rust.rb | 50 +++++++++++++++++++++++++++++++++++--------------
 1 file changed, 36 insertions(+), 14 deletions(-)

diff --git a/Formula/rust.rb b/Formula/rust.rb
index 64d42a594ede5..0a3b6ae86dc8b 100644
--- a/Formula/rust.rb
+++ b/Formula/rust.rb
@@ -4,8 +4,14 @@ class Rust < Formula
   license any_of: ["Apache-2.0", "MIT"]
 
   stable do
-    url "https://static.rust-lang.org/dist/rustc-1.48.0-src.tar.gz"
-    sha256 "0e763e6db47d5d6f91583284d2f989eacc49b84794d1443355b85c58d67ae43b"
+    if Hardware::CPU.arm?
+      url "https://static.rust-lang.org/dist/rustc-beta-src.tar.gz#1.49.0-beta"
+      sha256 "364fc8350d30f104595e458e51599369ffc5f796bb91b893372ba2631229963e"
+      version "1.48.0"
+    else
+      url "https://static.rust-lang.org/dist/rustc-1.48.0-src.tar.gz"
+      sha256 "0e763e6db47d5d6f91583284d2f989eacc49b84794d1443355b85c58d67ae43b"
+    end
 
     resource "cargo" do
       url "https://github.com/rust-lang/cargo.git",
@@ -42,8 +48,13 @@ class Rust < Formula
   resource "cargobootstrap" do
     on_macos do
       # From https://github.com/rust-lang/rust/blob/#{version}/src/stage0.txt
-      url "https://static.rust-lang.org/dist/2020-11-19/cargo-1.48.0-x86_64-apple-darwin.tar.gz"
-      sha256 "ce00d796cf5a9ac8d88d9df94c408e5d7ccd3541932a829eae833cc8e57efb15"
+      if Hardware::CPU.arch == :arm64
+        url "https://static.rust-lang.org/dist/2020-12-23/cargo-beta-aarch64-apple-darwin.tar.gz"
+        sha256 "efbc0e72533d4ca7def9a985feef4b3e43d24f1f6792815bdba9125af1f8ecdf"
+      else
+        url "https://static.rust-lang.org/dist/2020-11-19/cargo-1.48.0-x86_64-apple-darwin.tar.gz"
+        sha256 "ce00d796cf5a9ac8d88d9df94c408e5d7ccd3541932a829eae833cc8e57efb15"
+      end
     end
 
     on_linux do
@@ -78,17 +89,15 @@ def install
     else
       args << "--release-channel=stable"
     end
-    # Cross-compile arm64 with x86_64 bootstrap compiler.
-    if Hardware::CPU.arch == :arm64
-      args << "--build=x86_64-apple-darwin"
-      args << "--host=aarch64-apple-darwin"
-      args << "--target=aarch64-apple-darwin"
-      system "./configure", *args
-      system "arch", "-x86_64", "make"
-    else
-      system "./configure", *args
-      system "make"
+
+    if Hardware::CPU.arm?
+      # Fix for 1.49.0-beta, remove when the stable version is released
+      inreplace "src/stage0.txt", "1.48.0", "beta"
+      inreplace "src/stage0.txt", "2020-11-19", "2020-12-23"
     end
+
+    system "./configure", *args
+    system "make"
     system "make", "install"
 
     resource("cargobootstrap").stage do
@@ -117,6 +126,19 @@ def post_install
     end
   end
 
+  def caveats
+    s = ""
+
+    if Hardware::CPU.arm?
+      s += <<~EOS
+        This is a beta version of the Rust compiler for Apple Silicon
+        (rust 1.49.0-beta).
+      EOS
+    end
+
+    s
+  end
+
   test do
     system "#{bin}/rustdoc", "-h"
     (testpath/"hello.rs").write <<~EOS