Add \exhaustive\ annotation to exhaustive match blocks

Ponyc recently added an \exhaustive\ annotation for match expressions.
When present, the compiler will fail compilation if the match is not
exhaustive. This protects against future breakage if new variants are
added to a union type.

Author: SeanTAllen

cmd/cli.pony

@@ -8,7 +8,7 @@ primitive CLI
     : (Command | (U8, String))
   =>
     try
-      match CommandParser(_spec(default_prefix)?).parse(args, envs)
+      match \exhaustive\ CommandParser(_spec(default_prefix)?).parse(args, envs)
       | let c: Command => c
       | let h: CommandHelp => (0, h.help_string())
       | let e: SyntaxError => (1, e.string())

cmd/cloudsmith.pony

@@ -11,7 +11,7 @@ primitive Cloudsmith
 
   fun repo_url(repo': String): String =>
     let repo_name =
-      match consume repo'
+      match \exhaustive\ consume repo'
       | "nightly" => "nightlies"
       | "release" => "releases"
       | let s: String => s

cmd/http_handlers.pony

@@ -50,7 +50,7 @@ class QueryHandler is HTTPHandler
     end
 
   fun ref chunk(data: (String | Array[U8] val)) =>
-    match data
+    match \exhaustive\ data
     | let s: String => _buf.append(s)
     | let bs: Array[U8] val => _buf.append(String.from_array(bs))
     end

cmd/main.pony

@@ -26,7 +26,7 @@ actor Main is PonyupNotify
     let default_prefix: String val =
       _default_root.substring(0, -"/ponyup".size().isize())
     let command =
-      match recover val CLI.parse(_env.args, _env.vars, default_prefix) end
+      match \exhaustive\ recover val CLI.parse(_env.args, _env.vars, default_prefix) end
       | let c: Command val => c
       | (let exit_code: U8, let msg: String) =>
         if exit_code == 0 then
@@ -180,7 +180,7 @@ actor Main is PonyupNotify
     end
 
   be log(level: LogLevel, msg: String) =>
-    match level
+    match \exhaustive\ level
     | Info | Extra =>
       if (level is Info) or _verbose then
         if level is Extra then

cmd/packages.pony

@@ -131,7 +131,7 @@ primitive Packages
     if Platform.linux() then distro end
 
   fun platform_requires_distro(os: OS): Bool =>
-    match os
+    match \exhaustive\ os
     | Linux => true
     | Darwin => false
     | Windows => false

test/main.pony

@@ -48,7 +48,7 @@ class _TestParsePlatform is UnitTest
       ]
     for (input, expected) in tests.values() do
       h.log("input: " + input)
-      match expected
+      match \exhaustive\ expected
       | (let cpu: CPU, let os: OS, let distro: Distro) =>
         let pkg = Packages.from_string(input)?
         h.log("  => " + pkg.platform().string())