From 1a4f46ae7d185e14bc3ff76f078fc27cfff58e8f Mon Sep 17 00:00:00 2001
From: emekoi <emekankurumeh@outlook.com>
Date: Sat, 11 Apr 2020 01:01:37 -0500
Subject: [PATCH 1/3] add note about `@tagName` for non-exhaustive enums

---
 doc/langref.html.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/langref.html.in b/doc/langref.html.in
index cd1905ebfb..6531323532 100644
--- a/doc/langref.html.in
+++ b/doc/langref.html.in
@@ -8167,7 +8167,7 @@ test "vector @splat" {
       {#header_open|@tagName#}
       <pre>{#syntax#}@tagName(value: var) []const u8{#endsyntax#}</pre>
       <p>
-      Converts an enum value or union value to a slice of bytes representing the name.
+      Converts an enum value or union value to a slice of bytes representing the name. Not valid for unamed fields in non-exhaustive enums.
       </p>
       {#header_close#}
 

From de08d283da8f8f4da8dfaee61c0bdd85c813c938 Mon Sep 17 00:00:00 2001
From: emekoi <emekankurumeh@outlook.com>
Date: Sat, 11 Apr 2020 15:18:54 -0500
Subject: [PATCH 2/3] fix compilation under mingw

---
 CMakeLists.txt             |  3 +++
 src-self-hosted/stage2.zig | 24 ++++++++++++++++++++----
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 279156c93c..092cdb7a70 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -454,6 +454,9 @@ if("${ZIG_TARGET_TRIPLE}" STREQUAL "native")
       WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}"
   )
   set(ZIG_EXECUTABLE "${zig_BINARY_DIR}/zig")
+  if (WIN32)
+    set(ZIG_EXECUTABLE "${ZIG_EXECUTABLE}.exe")
+  endif()
 else()
   add_custom_target(zig_build_libstage2 ALL
       COMMAND "${ZIG_EXECUTABLE}" ${BUILD_LIBSTAGE2_ARGS}
diff --git a/src-self-hosted/stage2.zig b/src-self-hosted/stage2.zig
index 9d8c8446d5..aba4706f09 100644
--- a/src-self-hosted/stage2.zig
+++ b/src-self-hosted/stage2.zig
@@ -897,6 +897,22 @@ export fn stage2_libc_render(stage1_libc: *Stage2LibCInstallation, output_file:
     return .None;
 }
 
+fn enumToString(value: var, type_name: []const u8) ![]const u8 {
+    switch (@typeInfo(@TypeOf(value))) {
+        .Enum => |e| {
+            if (e.is_exhaustive) {
+                return std.fmt.allocPrint(std.heap.c_allocator, ".{}", .{@tagName(value)});
+            } else {
+                return std.fmt.allocPrint(std.heap.c_allocator,
+                    "@intToEnum({}, {})",
+                    .{type_name, @enumToInt(value)}
+                );
+            }
+        },
+        else => unreachable 
+    }
+}
+
 // ABI warning
 const Stage2Target = extern struct {
     arch: c_int,
@@ -1114,13 +1130,13 @@ const Stage2Target = extern struct {
 
             .windows => try os_builtin_str_buffer.outStream().print(
                 \\ .windows = .{{
-                \\        .min = .{},
-                \\        .max = .{},
+                \\        .min = {},
+                \\        .max = {},
                 \\    }}}},
                 \\
             , .{
-                @tagName(target.os.version_range.windows.min),
-                @tagName(target.os.version_range.windows.max),
+                try enumToString(target.os.version_range.windows.min, "Target.Os.WindowsVersion"),
+                try enumToString(target.os.version_range.windows.max, "Target.Os.WindowsVersion")
             }),
         }
         try os_builtin_str_buffer.appendSlice("};\n");

From eefe6956fde0adc2b0b56fdb6d22e06e2543219e Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Sat, 11 Apr 2020 16:43:19 -0400
Subject: [PATCH 3/3] clarify what "not valid" means

---
 doc/langref.html.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/langref.html.in b/doc/langref.html.in
index 6531323532..bb824076d6 100644
--- a/doc/langref.html.in
+++ b/doc/langref.html.in
@@ -8167,7 +8167,7 @@ test "vector @splat" {
       {#header_open|@tagName#}
       <pre>{#syntax#}@tagName(value: var) []const u8{#endsyntax#}</pre>
       <p>
-      Converts an enum value or union value to a slice of bytes representing the name. Not valid for unamed fields in non-exhaustive enums.
+      Converts an enum value or union value to a slice of bytes representing the name.</p><p>If the enum is non-exhaustive and the tag value does not map to a name, it invokes safety-checked {#link|Undefined Behavior#}.
       </p>
       {#header_close#}