Specify default exe extension on wasm32 to be .wasm

Specify default exe extension on wasm32 to be .wasm, following the convention in other WebAssembly toolchains.

Cabal/src/Distribution/Simple/BuildPaths.hs

@@ -235,8 +235,9 @@ mkGenericSharedBundledLibName platform comp lib
 -- | Default extension for executable files on the current platform.
 -- (typically @\"\"@ on Unix and @\"exe\"@ on Windows or OS\/2)
 exeExtension :: Platform -> String
-exeExtension (Platform _arch os) = case os of
-                   Windows -> "exe"
+exeExtension platform = case platform of
+                   Platform _ Windows -> "exe"
+                   Platform Wasm32 _  -> "wasm"
                    _       -> ""
 
 -- | Extension for object files. For GHC the extension is @\"o\"@.

Cabal/src/Distribution/Simple/Utils.hs

@@ -1535,12 +1535,13 @@ dropExeExtension filepath =
 -- | List of possible executable file extensions on the current build
 -- platform.
 exeExtensions :: [String]
-exeExtensions = case buildOS of
+exeExtensions = case (buildArch, buildOS) of
   -- Possible improvement: on Windows, read the list of extensions from the
   -- PATHEXT environment variable. By default PATHEXT is ".com; .exe; .bat;
   -- .cmd".
-  Windows -> ["", "exe"]
-  Ghcjs   -> ["", "exe"]
+  (_, Windows) -> ["", "exe"]
+  (_, Ghcjs)   -> ["", "exe"]
+  (Wasm32, _)  -> ["", "wasm"]
   _       -> [""]
 
 -- ------------------------------------------------------------

changelog.d/pr-8633

@@ -0,0 +1,7 @@
+synopsis: Specify default exe extension on wasm32 to be .wasm
+packages: Cabal
+prs: #8633
+issues:
+description: {
+  Specify default exe extension on wasm32 to be .wasm, following the convention in other WebAssembly toolchains.
+}