flambda-backend: Turn the (most mature) layouts extension on by default (#2241)

Author: ccasin

boot/menhir/parser.ml

@@ -147,6 +147,9 @@ let prepare_error err =
        @{<hint>Hint@}: Mutable sequences of bytes are available in \
        the Bytes module.\n\
        @{<hint>Hint@}: Did you mean to use 'Bytes.set'?"
+  | Missing_unboxed_literal_suffix loc ->
+    Location.errorf ~loc
+      "Syntax error: Unboxed integer literals require width suffixes."
 
 let () =
   Location.register_error_of_exn

parsing/parse.ml

@@ -992,7 +992,8 @@ let unboxed_int sloc int_loc sign (n, m) =
       Constant.unboxed ~loc:int_loc (Integer (with_sign sign n, m))
   | None ->
       if Language_extension.is_enabled unboxed_literals_extension then
-        expecting int_loc "unboxed integer literal with type-specifying suffix"
+        raise
+          Syntaxerr.(Error(Missing_unboxed_literal_suffix (make_loc int_loc)))
       else
         not_expecting sloc "line number directive"
 

parsing/parser.mly

@@ -25,6 +25,7 @@ type error =
   | Ill_formed_ast of Location.t * string
   | Invalid_package_type of Location.t * string
   | Removed_string_set of Location.t
+  | Missing_unboxed_literal_suffix of Location.t
 
 exception Error of error
 exception Escape_error
@@ -39,6 +40,7 @@ let location_of_error = function
   | Invalid_package_type (l, _)
   | Expecting (l, _)
   | Removed_string_set l -> l
+  | Missing_unboxed_literal_suffix l -> l
 
 
 let ill_formed_ast loc s =

parsing/syntaxerr.ml

@@ -30,6 +30,7 @@ type error =
   | Ill_formed_ast of Location.t * string
   | Invalid_package_type of Location.t * string
   | Removed_string_set of Location.t
+  | Missing_unboxed_literal_suffix of Location.t
 
 exception Error of error
 exception Escape_error

parsing/syntaxerr.mli

@@ -1,8 +1,7 @@
 (* TEST
-   flags = '-extension layouts'
    * expect
 *)
-(* CR layouts: Using [-extension layouts] here is not backward-compatible.
+(* CR layouts: Using layout annotations here is not backward-compatible.
    We can delete this when internal ticket 1110 is resolved.
 *)
 

testsuite/tests/letrec-check/unboxed.ml

@@ -1,4 +1,4 @@
 File "pr6604.ml", line 9, characters 0-2:
 9 | #1
     ^^
-Error: Syntax error: line number directive not expected.
+Error: Syntax error: Unboxed integer literals require width suffixes.

testsuite/tests/parsing/pr6604.compilers.reference

@@ -1,4 +1,4 @@
 File "pr6604_2.ml", line 9, characters 1-3:
 9 |  #1 "pr6604.ml"
      ^^
-Error: Syntax error: line number directive not expected.
+Error: Syntax error: Unboxed integer literals require width suffixes.

testsuite/tests/parsing/pr6604_2.compilers.reference

@@ -1,6 +1,5 @@
 (* TEST
    * flambda2
-   flags = "-extension layouts"
    ** native
 *)
 

testsuite/tests/typing-layouts-bits32/alloc.ml

@@ -1,10 +1,9 @@
 (* TEST
+   * expect
    * expect
    flags = "-extension layouts_alpha"
    * expect
    flags = "-extension layouts_beta"
-   * expect
-   flags = "-extension layouts"
 *)
 
 (* This file contains typing tests for the layout [bits32].