Make sure the Jane syntax extensions don't depend on our compiler cha…

…nges (ocaml-flambda#1777)

* Revert `asttypes.mli` to the upstream version

* Move our new asttypes-level types into the new `jane_asttypes.mli`

* Move printing of const layouts/layout annotations to `Jane_syntax`

* Remove calls to `Location.ghostify` and explain why

* Remove calls to new `Printast` functions

* Explain why we want the buildable-with-upstream restriction

* Respond to review

ocaml/.depend

@@ -142,7 +142,6 @@ utils/language_extension_kernel.cmo : \
 utils/language_extension_kernel.cmx : \
     utils/language_extension_kernel.cmi
 utils/language_extension_kernel.cmi :
-utils/language_extension_kernel_intf.cmi :
 utils/lazy_backtrack.cmo : \
     utils/lazy_backtrack.cmi
 utils/lazy_backtrack.cmx : \
@@ -308,26 +307,27 @@ parsing/ast_iterator.cmo : \
     parsing/parsetree.cmi \
     parsing/location.cmi \
     parsing/jane_syntax.cmi \
-    parsing/asttypes.cmi \
+    parsing/jane_asttypes.cmi \
     parsing/ast_iterator.cmi
 parsing/ast_iterator.cmx : \
     parsing/parsetree.cmi \
     parsing/location.cmx \
     parsing/jane_syntax.cmx \
-    parsing/asttypes.cmi \
+    parsing/jane_asttypes.cmi \
     parsing/ast_iterator.cmi
 parsing/ast_iterator.cmi : \
     parsing/parsetree.cmi \
     parsing/location.cmi \
     parsing/jane_syntax.cmi \
-    parsing/asttypes.cmi
+    parsing/jane_asttypes.cmi
 parsing/ast_mapper.cmo : \
     parsing/parsetree.cmi \
     utils/misc.cmi \
     parsing/longident.cmi \
     parsing/location.cmi \
     utils/load_path.cmi \
     parsing/jane_syntax.cmi \
+    parsing/jane_asttypes.cmi \
     parsing/docstrings.cmi \
     utils/config.cmi \
     utils/clflags.cmi \
@@ -341,6 +341,7 @@ parsing/ast_mapper.cmx : \
     parsing/location.cmx \
     utils/load_path.cmx \
     parsing/jane_syntax.cmx \
+    parsing/jane_asttypes.cmi \
     parsing/docstrings.cmx \
     utils/config.cmx \
     utils/clflags.cmx \
@@ -351,7 +352,7 @@ parsing/ast_mapper.cmi : \
     parsing/parsetree.cmi \
     parsing/location.cmi \
     parsing/jane_syntax.cmi \
-    parsing/asttypes.cmi
+    parsing/jane_asttypes.cmi
 parsing/asttypes.cmi : \
     parsing/location.cmi
 parsing/attr_helper.cmo : \
@@ -377,6 +378,7 @@ parsing/builtin_attributes.cmo : \
     parsing/longident.cmi \
     parsing/location.cmi \
     utils/language_extension.cmi \
+    parsing/jane_asttypes.cmi \
     utils/config.cmi \
     utils/clflags.cmi \
     parsing/asttypes.cmi \
@@ -390,6 +392,7 @@ parsing/builtin_attributes.cmx : \
     parsing/longident.cmx \
     parsing/location.cmx \
     utils/language_extension.cmx \
+    parsing/jane_asttypes.cmi \
     utils/config.cmx \
     utils/clflags.cmx \
     parsing/asttypes.cmi \
@@ -400,7 +403,7 @@ parsing/builtin_attributes.cmi : \
     parsing/parsetree.cmi \
     utils/misc.cmi \
     parsing/location.cmi \
-    parsing/asttypes.cmi
+    parsing/jane_asttypes.cmi
 parsing/camlinternalMenhirLib.cmo : \
     parsing/camlinternalMenhirLib.cmi
 parsing/camlinternalMenhirLib.cmx : \
@@ -412,6 +415,7 @@ parsing/depend.cmo : \
     parsing/longident.cmi \
     parsing/location.cmi \
     parsing/jane_syntax.cmi \
+    parsing/jane_asttypes.cmi \
     utils/clflags.cmi \
     parsing/builtin_attributes.cmi \
     parsing/asttypes.cmi \
@@ -422,6 +426,7 @@ parsing/depend.cmx : \
     parsing/longident.cmx \
     parsing/location.cmx \
     parsing/jane_syntax.cmx \
+    parsing/jane_asttypes.cmi \
     utils/clflags.cmx \
     parsing/builtin_attributes.cmx \
     parsing/asttypes.cmi \
@@ -443,28 +448,39 @@ parsing/docstrings.cmx : \
 parsing/docstrings.cmi : \
     parsing/parsetree.cmi \
     parsing/location.cmi
+parsing/jane_asttypes.cmi : \
+    parsing/asttypes.cmi
 parsing/jane_syntax.cmo : \
     parsing/printast.cmi \
     parsing/parsetree.cmi \
+    utils/misc.cmi \
     parsing/longident.cmi \
     parsing/location.cmi \
+    utils/language_extension_kernel.cmi \
+    utils/language_extension.cmi \
     parsing/jane_syntax_parsing.cmi \
+    parsing/jane_asttypes.cmi \
     parsing/asttypes.cmi \
     parsing/ast_helper.cmi \
     parsing/jane_syntax.cmi
 parsing/jane_syntax.cmx : \
     parsing/printast.cmx \
     parsing/parsetree.cmi \
+    utils/misc.cmx \
     parsing/longident.cmx \
     parsing/location.cmx \
+    utils/language_extension_kernel.cmx \
+    utils/language_extension.cmx \
     parsing/jane_syntax_parsing.cmx \
+    parsing/jane_asttypes.cmi \
     parsing/asttypes.cmi \
     parsing/ast_helper.cmx \
     parsing/jane_syntax.cmi
 parsing/jane_syntax.cmi : \
     parsing/parsetree.cmi \
     parsing/longident.cmi \
     parsing/location.cmi \
+    parsing/jane_asttypes.cmi \
     parsing/docstrings.cmi \
     parsing/asttypes.cmi
 parsing/jane_syntax_parsing.cmo : \
@@ -550,6 +566,7 @@ parsing/parser.cmo : \
     utils/language_extension.cmi \
     parsing/jane_syntax_parsing.cmi \
     parsing/jane_syntax.cmi \
+    parsing/jane_asttypes.cmi \
     parsing/docstrings.cmi \
     utils/clflags.cmi \
     parsing/camlinternalMenhirLib.cmi \
@@ -565,6 +582,7 @@ parsing/parser.cmx : \
     utils/language_extension.cmx \
     parsing/jane_syntax_parsing.cmx \
     parsing/jane_syntax.cmx \
+    parsing/jane_asttypes.cmi \
     parsing/docstrings.cmx \
     utils/clflags.cmx \
     parsing/camlinternalMenhirLib.cmx \
@@ -587,6 +605,7 @@ parsing/pprintast.cmo : \
     parsing/parsetree.cmi \
     parsing/longident.cmi \
     parsing/location.cmi \
+    utils/language_extension.cmi \
     parsing/jane_syntax.cmi \
     parsing/asttypes.cmi \
     parsing/ast_helper.cmi \
@@ -596,6 +615,7 @@ parsing/pprintast.cmx : \
     parsing/parsetree.cmi \
     parsing/longident.cmx \
     parsing/location.cmx \
+    utils/language_extension.cmx \
     parsing/jane_syntax.cmx \
     parsing/asttypes.cmi \
     parsing/ast_helper.cmx \
@@ -607,19 +627,21 @@ parsing/printast.cmo : \
     parsing/parsetree.cmi \
     parsing/longident.cmi \
     parsing/location.cmi \
+    parsing/jane_asttypes.cmi \
     utils/clflags.cmi \
     parsing/asttypes.cmi \
     parsing/printast.cmi
 parsing/printast.cmx : \
     parsing/parsetree.cmi \
     parsing/longident.cmx \
     parsing/location.cmx \
+    parsing/jane_asttypes.cmi \
     utils/clflags.cmx \
     parsing/asttypes.cmi \
     parsing/printast.cmi
 parsing/printast.cmi : \
     parsing/parsetree.cmi \
-    parsing/asttypes.cmi
+    parsing/jane_asttypes.cmi
 parsing/syntaxerr.cmo : \
     parsing/printast.cmi \
     parsing/location.cmi \
@@ -1041,25 +1063,25 @@ typing/layouts.cmo : \
     utils/misc.cmi \
     parsing/location.cmi \
     utils/language_extension.cmi \
+    parsing/jane_asttypes.cmi \
     typing/ident.cmi \
     parsing/builtin_attributes.cmi \
-    parsing/asttypes.cmi \
     typing/layouts.cmi
 typing/layouts.cmx : \
     typing/path.cmx \
     utils/misc.cmx \
     parsing/location.cmx \
     utils/language_extension.cmx \
+    parsing/jane_asttypes.cmi \
     typing/ident.cmx \
     parsing/builtin_attributes.cmx \
-    parsing/asttypes.cmi \
     typing/layouts.cmi
 typing/layouts.cmi : \
     typing/path.cmi \
     parsing/parsetree.cmi \
     parsing/location.cmi \
-    typing/ident.cmi \
-    parsing/asttypes.cmi
+    parsing/jane_asttypes.cmi \
+    typing/ident.cmi
 typing/mode.cmo : \
     utils/misc.cmi \
     typing/mode.cmi
@@ -1116,6 +1138,7 @@ typing/oprint.cmx : \
 typing/oprint.cmi : \
     typing/outcometree.cmi
 typing/outcometree.cmi : \
+    parsing/jane_asttypes.cmi \
     parsing/asttypes.cmi
 typing/parmatch.cmo : \
     utils/warnings.cmi \
@@ -1511,30 +1534,36 @@ typing/subst.cmi : \
     typing/ident.cmi
 typing/tast_iterator.cmo : \
     typing/typedtree.cmi \
+    parsing/jane_asttypes.cmi \
     typing/env.cmi \
     parsing/asttypes.cmi \
     typing/tast_iterator.cmi
 typing/tast_iterator.cmx : \
     typing/typedtree.cmx \
+    parsing/jane_asttypes.cmi \
     typing/env.cmx \
     parsing/asttypes.cmi \
     typing/tast_iterator.cmi
 typing/tast_iterator.cmi : \
     typing/typedtree.cmi \
+    parsing/jane_asttypes.cmi \
     typing/env.cmi \
     parsing/asttypes.cmi
 typing/tast_mapper.cmo : \
     typing/typedtree.cmi \
+    parsing/jane_asttypes.cmi \
     typing/env.cmi \
     parsing/asttypes.cmi \
     typing/tast_mapper.cmi
 typing/tast_mapper.cmx : \
     typing/typedtree.cmx \
+    parsing/jane_asttypes.cmi \
     typing/env.cmx \
     parsing/asttypes.cmi \
     typing/tast_mapper.cmi
 typing/tast_mapper.cmi : \
     typing/typedtree.cmi \
+    parsing/jane_asttypes.cmi \
     typing/env.cmi \
     parsing/asttypes.cmi
 typing/typeclass.cmo : \
@@ -1556,6 +1585,7 @@ typing/typeclass.cmo : \
     parsing/longident.cmi \
     parsing/location.cmi \
     typing/layouts.cmi \
+    parsing/jane_syntax.cmi \
     typing/includeclass.cmi \
     typing/ident.cmi \
     typing/errortrace.cmi \
@@ -1587,6 +1617,7 @@ typing/typeclass.cmx : \
     parsing/longident.cmx \
     parsing/location.cmx \
     typing/layouts.cmx \
+    parsing/jane_syntax.cmx \
     typing/includeclass.cmx \
     typing/ident.cmx \
     typing/errortrace.cmx \
@@ -1873,6 +1904,7 @@ typing/typedtree.cmo : \
     parsing/longident.cmi \
     parsing/location.cmi \
     typing/layouts.cmi \
+    parsing/jane_asttypes.cmi \
     typing/ident.cmi \
     typing/env.cmi \
     parsing/asttypes.cmi \
@@ -1888,6 +1920,7 @@ typing/typedtree.cmx : \
     parsing/longident.cmx \
     parsing/location.cmx \
     typing/layouts.cmx \
+    parsing/jane_asttypes.cmi \
     typing/ident.cmx \
     typing/env.cmx \
     parsing/asttypes.cmi \
@@ -1903,6 +1936,7 @@ typing/typedtree.cmi : \
     parsing/longident.cmi \
     parsing/location.cmi \
     typing/layouts.cmi \
+    parsing/jane_asttypes.cmi \
     typing/ident.cmi \
     typing/env.cmi \
     parsing/asttypes.cmi
@@ -2108,6 +2142,7 @@ typing/typetexp.cmo : \
     typing/layouts.cmi \
     utils/language_extension.cmi \
     parsing/jane_syntax.cmi \
+    parsing/jane_asttypes.cmi \
     typing/errortrace.cmi \
     typing/env.cmi \
     typing/ctype.cmi \
@@ -2133,6 +2168,7 @@ typing/typetexp.cmx : \
     typing/layouts.cmx \
     utils/language_extension.cmx \
     parsing/jane_syntax.cmx \
+    parsing/jane_asttypes.cmi \
     typing/errortrace.cmx \
     typing/env.cmx \
     typing/ctype.cmx \
@@ -2152,6 +2188,7 @@ typing/typetexp.cmi : \
     parsing/location.cmi \
     typing/layouts.cmi \
     utils/language_extension.cmi \
+    parsing/jane_asttypes.cmi \
     typing/errortrace.cmi \
     typing/env.cmi \
     parsing/asttypes.cmi
@@ -3685,13 +3722,15 @@ middle_end/convert_primitives.cmo : \
     lambda/printlambda.cmi \
     typing/primitive.cmi \
     utils/misc.cmi \
+    typing/layouts.cmi \
     lambda/lambda.cmi \
     middle_end/clambda_primitives.cmi \
     middle_end/convert_primitives.cmi
 middle_end/convert_primitives.cmx : \
     lambda/printlambda.cmx \
     typing/primitive.cmx \
     utils/misc.cmx \
+    typing/layouts.cmx \
     lambda/lambda.cmx \
     middle_end/clambda_primitives.cmx \
     middle_end/convert_primitives.cmi
@@ -3817,7 +3856,6 @@ lambda/lambda.cmo : \
     utils/misc.cmi \
     parsing/longident.cmi \
     parsing/location.cmi \
-    typing/layouts.cmi \
     typing/ident.cmi \
     typing/env.cmi \
     lambda/debuginfo.cmi \
@@ -3833,7 +3871,6 @@ lambda/lambda.cmx : \
     utils/misc.cmx \
     parsing/longident.cmx \
     parsing/location.cmx \
-    typing/layouts.cmx \
     typing/ident.cmx \
     typing/env.cmx \
     lambda/debuginfo.cmx \
@@ -3848,7 +3885,6 @@ lambda/lambda.cmi : \
     typing/primitive.cmi \
     typing/path.cmi \
     parsing/location.cmi \
-    typing/layouts.cmi \
     typing/ident.cmi \
     typing/env.cmi \
     lambda/debuginfo.cmi \