tweaks

zth · zth · commit 14069cf59e9f · 2025-08-23T08:44:18.000+02:00
diff --git a/compiler/frontend/bs_builtin_ppx.ml b/compiler/frontend/bs_builtin_ppx.ml
@@ -462,8 +462,13 @@ let structure_item_mapper (self : mapper) (str : Parsetree.structure_item) :
           Ast_attributes.has_unwrap_attr vb.pvb_attributes)
         vbs
     in
-    Bs_syntaxerr.err vb.pvb_pat.ppat_loc
-      (LetUnwrap_not_supported_in_position `Toplevel)
+    if not (Experimental_features.is_enabled Experimental_features.LetUnwrap)
+    then
+      Bs_syntaxerr.err vb.pvb_pat.ppat_loc
+        (Experimental_feature_not_enabled LetUnwrap)
+    else
+      Bs_syntaxerr.err vb.pvb_pat.ppat_loc
+        (LetUnwrap_not_supported_in_position `Toplevel)
   | Pstr_type (rf, tdcls) (* [ {ptype_attributes} as tdcl ] *) ->
     Ast_tdcls.handle_tdcls_in_stru self str rf tdcls
   | Pstr_primitive prim
diff --git a/compiler/frontend/bs_syntaxerr.ml b/compiler/frontend/bs_syntaxerr.ml
@@ -88,7 +88,7 @@ let pp_error fmt err =
     | Experimental_feature_not_enabled feature ->
       Printf.sprintf
         "Experimental feature not enabled: %s. Enable it by setting \"%s\" to \
-         true under \"experimentalFeatures\" in rescript.json"
+         true under \"experimentalFeatures\" in rescript.json."
         (Experimental_features.to_string feature)
         (Experimental_features.to_string feature)
     | LetUnwrap_not_supported_in_position hint -> (
diff --git a/docs/docson/build-schema.json b/docs/docson/build-schema.json
@@ -491,7 +491,7 @@
       "properties": {
         "LetUnwrap": {
           "type": "boolean",
-          "description": "Enable let? syntax."
+          "description": "Enable `let?` syntax."
         }
       },
       "additionalProperties": false
diff --git a/rewatch/CompilerConfigurationSpec.md b/rewatch/CompilerConfigurationSpec.md
@@ -121,7 +121,7 @@ An object of feature flags to enable experimental compiler behavior. Only suppor
 
 Currently supported features:
 
-- LetUnwrap: Enable the `let?` transformation.
+- LetUnwrap: Enable `let?` syntax.
 
 ### Warnings
 
diff --git a/tests/build_tests/super_errors/expected/feature_letunwrap_not_enabled.res.expected b/tests/build_tests/super_errors/expected/feature_letunwrap_not_enabled.res.expected
@@ -8,4 +8,4 @@
   5 [2m│[0m   Ok()
   6 [2m│[0m }
 
-  Experimental feature not enabled: LetUnwrap. Enable it by setting "LetUnwrap" to true under "experimentalFeatures" in rescript.json
+  Experimental feature not enabled: LetUnwrap. Enable it by setting "LetUnwrap" to true under "experimentalFeatures" in rescript.json.
diff --git a/tests/build_tests/super_errors/expected/let_unwrap_on_top_level.res.expected b/tests/build_tests/super_errors/expected/let_unwrap_on_top_level.res.expected
@@ -1,10 +1,10 @@
 
   [1;31mWe've found a bug for you![0m
-  [36m/.../fixtures/let_unwrap_on_top_level.res[0m:[2m3:6-10[0m
+  [36m/.../fixtures/let_unwrap_on_top_level.res[0m:[2m5:6-10[0m
 
-  1 [2m│[0m let x = Ok(1)
-  2 [2m│[0m 
-  [1;31m3[0m [2m│[0m let? [1;31mOk(_)[0m = x
+  3 [2m│[0m let x = Ok(1)
   4 [2m│[0m 
+  [1;31m5[0m [2m│[0m let? [1;31mOk(_)[0m = x
+  6 [2m│[0m 
 
   `let?` is not allowed for top-level bindings.
diff --git a/tests/build_tests/super_errors/expected/let_unwrap_on_top_level_not_enabled.res.expected b/tests/build_tests/super_errors/expected/let_unwrap_on_top_level_not_enabled.res.expected
@@ -0,0 +1,10 @@
+
+  [1;31mWe've found a bug for you![0m
+  [36m/.../fixtures/let_unwrap_on_top_level_not_enabled.res[0m:[2m3:6-10[0m
+
+  1 [2m│[0m let x = Ok(1)
+  2 [2m│[0m 
+  [1;31m3[0m [2m│[0m let? [1;31mOk(_)[0m = x
+  4 [2m│[0m 
+
+  Experimental feature not enabled: LetUnwrap. Enable it by setting "LetUnwrap" to true under "experimentalFeatures" in rescript.json.
diff --git a/tests/build_tests/super_errors/fixtures/let_unwrap_on_top_level.res b/tests/build_tests/super_errors/fixtures/let_unwrap_on_top_level.res
@@ -1,3 +1,5 @@
+@@config({flags: ["-enable-experimental", "LetUnwrap"]})
+
 let x = Ok(1)
 
 let? Ok(_) = x
diff --git a/tests/build_tests/super_errors/fixtures/let_unwrap_on_top_level_not_enabled.res b/tests/build_tests/super_errors/fixtures/let_unwrap_on_top_level_not_enabled.res
@@ -0,0 +1,3 @@
+let x = Ok(1)
+
+let? Ok(_) = x

Original file line number	Diff line number	Diff line change
`@@ -491,7 +491,7 @@`
`491`	`491`	`"properties": {`
`492`	`492`	`"LetUnwrap": {`
`493`	`493`	`"type": "boolean",`
`494`		`- "description": "Enable let? syntax."`
	`494`	+ "description": "Enable `let?` syntax."
`495`	`495`	`}`
`496`	`496`	`},`
`497`	`497`	`"additionalProperties": false`
-Original file line number
+Diff line change
 [2m│[0m   Ok()
 [2m│[0m }
 -  Experimental feature not enabled: LetUnwrap. Enable it by setting "LetUnwrap" to true under "experimentalFeatures" in rescript.json
 +  Experimental feature not enabled: LetUnwrap. Enable it by setting "LetUnwrap" to true under "experimentalFeatures" in rescript.json.
-Original file line number
+Diff line change
@@ @@ -1,10 +1,10 @@ @@
   [1;31mWe've found a bug for you![0m
 -  [36m/.../fixtures/let_unwrap_on_top_level.res[0m:[2m3:6-10[0m
 +  [36m/.../fixtures/let_unwrap_on_top_level.res[0m:[2m5:6-10[0m
 -  1 [2m│[0m let x = Ok(1)
 -  2 [2m│[0m
 -  [1;31m3[0m [2m│[0m let? [1;31mOk(_)[0m = x
 +  3 [2m│[0m let x = Ok(1)
 [2m│[0m
 +  [1;31m5[0m [2m│[0m let? [1;31mOk(_)[0m = x
 +  6 [2m│[0m
   `let?` is not allowed for top-level bindings.
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+let x = Ok(1)`
	`2`	`+`
	`3`	`+let? Ok(_) = x`