MPR#7574: hightlight differences in type error messages

.depend

@@ -186,6 +186,11 @@ typing/datarepr.cmx : typing/types.cmx typing/path.cmx parsing/location.cmx \
     typing/ident.cmx typing/btype.cmx parsing/asttypes.cmi \
     typing/datarepr.cmi
 typing/datarepr.cmi : typing/types.cmi typing/path.cmi typing/ident.cmi
+typing/difftree.cmo : typing/outcometree.cmi utils/misc.cmi \
+    utils/clflags.cmi parsing/asttypes.cmi typing/difftree.cmi
+typing/difftree.cmx : typing/outcometree.cmx utils/misc.cmx \
+    utils/clflags.cmx parsing/asttypes.cmi typing/difftree.cmi
+typing/difftree.cmi : typing/outcometree.cmi
 typing/env.cmo : utils/warnings.cmi typing/types.cmi utils/tbl.cmi \
     typing/subst.cmi typing/predef.cmi typing/path.cmi utils/misc.cmi \
     parsing/longident.cmi parsing/location.cmi typing/ident.cmi \
@@ -230,15 +235,15 @@ typing/includecore.cmi : typing/types.cmi typing/typedtree.cmi \
     parsing/location.cmi typing/ident.cmi typing/env.cmi
 typing/includemod.cmo : typing/types.cmi typing/typedtree.cmi utils/tbl.cmi \
     typing/subst.cmi typing/printtyp.cmi typing/primitive.cmi typing/path.cmi \
-    typing/mtype.cmi utils/misc.cmi parsing/location.cmi \
+    typing/oprint.cmi typing/mtype.cmi utils/misc.cmi parsing/location.cmi \
     typing/includecore.cmi typing/includeclass.cmi typing/ident.cmi \
-    typing/env.cmi typing/ctype.cmi typing/cmt_format.cmi utils/clflags.cmi \
+    typing/env.cmi typing/difftree.cmi typing/ctype.cmi typing/cmt_format.cmi \
     parsing/builtin_attributes.cmi typing/btype.cmi typing/includemod.cmi
 typing/includemod.cmx : typing/types.cmx typing/typedtree.cmx utils/tbl.cmx \
     typing/subst.cmx typing/printtyp.cmx typing/primitive.cmx typing/path.cmx \
-    typing/mtype.cmx utils/misc.cmx parsing/location.cmx \
+    typing/oprint.cmx typing/mtype.cmx utils/misc.cmx parsing/location.cmx \
     typing/includecore.cmx typing/includeclass.cmx typing/ident.cmx \
-    typing/env.cmx typing/ctype.cmx typing/cmt_format.cmx utils/clflags.cmx \
+    typing/env.cmx typing/difftree.cmx typing/ctype.cmx typing/cmt_format.cmx \
     parsing/builtin_attributes.cmx typing/btype.cmx typing/includemod.cmi
 typing/includemod.cmi : typing/types.cmi typing/typedtree.cmi \
     typing/path.cmi parsing/location.cmi typing/includecore.cmi \
@@ -255,9 +260,11 @@ typing/mtype.cmi : typing/types.cmi typing/path.cmi typing/ident.cmi \
     typing/env.cmi
 typing/oprint.cmo : typing/outcometree.cmi parsing/asttypes.cmi \
     typing/oprint.cmi
-typing/oprint.cmx : typing/outcometree.cmi parsing/asttypes.cmi \
+typing/oprint.cmx : typing/outcometree.cmx parsing/asttypes.cmi \
     typing/oprint.cmi
 typing/oprint.cmi : typing/outcometree.cmi
+typing/outcometree.cmo : parsing/asttypes.cmi typing/outcometree.cmi
+typing/outcometree.cmx : parsing/asttypes.cmi typing/outcometree.cmi
 typing/outcometree.cmi : parsing/asttypes.cmi
 typing/parmatch.cmo : utils/warnings.cmi typing/untypeast.cmi \
     typing/types.cmi typing/typedtreeIter.cmi typing/typedtree.cmi \
@@ -274,8 +281,8 @@ typing/parmatch.cmx : utils/warnings.cmx typing/untypeast.cmx \
     utils/config.cmx typing/btype.cmx parsing/asttypes.cmi \
     parsing/ast_helper.cmx typing/parmatch.cmi
 typing/parmatch.cmi : typing/types.cmi typing/typedtree.cmi \
-    parsing/parsetree.cmi parsing/longident.cmi parsing/location.cmi \
-    typing/env.cmi parsing/asttypes.cmi
+    parsing/parsetree.cmi parsing/location.cmi typing/env.cmi \
+    parsing/asttypes.cmi
 typing/path.cmo : typing/ident.cmi typing/path.cmi
 typing/path.cmx : typing/ident.cmx typing/path.cmi
 typing/path.cmi : typing/ident.cmi
@@ -289,7 +296,7 @@ typing/predef.cmi : typing/types.cmi typing/path.cmi typing/ident.cmi
 typing/primitive.cmo : parsing/parsetree.cmi typing/outcometree.cmi \
     utils/misc.cmi parsing/location.cmi parsing/attr_helper.cmi \
     typing/primitive.cmi
-typing/primitive.cmx : parsing/parsetree.cmi typing/outcometree.cmi \
+typing/primitive.cmx : parsing/parsetree.cmi typing/outcometree.cmx \
     utils/misc.cmx parsing/location.cmx parsing/attr_helper.cmx \
     typing/primitive.cmi
 typing/primitive.cmi : parsing/parsetree.cmi typing/outcometree.cmi \
@@ -303,14 +310,14 @@ typing/printtyp.cmo : typing/types.cmi typing/primitive.cmi \
     typing/predef.cmi typing/path.cmi parsing/parsetree.cmi \
     typing/outcometree.cmi typing/oprint.cmi utils/misc.cmi \
     parsing/longident.cmi parsing/location.cmi typing/ident.cmi \
-    typing/env.cmi typing/ctype.cmi utils/clflags.cmi \
+    typing/env.cmi typing/difftree.cmi typing/ctype.cmi utils/clflags.cmi \
     parsing/builtin_attributes.cmi typing/btype.cmi parsing/asttypes.cmi \
     typing/printtyp.cmi
 typing/printtyp.cmx : typing/types.cmx typing/primitive.cmx \
     typing/predef.cmx typing/path.cmx parsing/parsetree.cmi \
-    typing/outcometree.cmi typing/oprint.cmx utils/misc.cmx \
+    typing/outcometree.cmx typing/oprint.cmx utils/misc.cmx \
     parsing/longident.cmx parsing/location.cmx typing/ident.cmx \
-    typing/env.cmx typing/ctype.cmx utils/clflags.cmx \
+    typing/env.cmx typing/difftree.cmx typing/ctype.cmx utils/clflags.cmx \
     parsing/builtin_attributes.cmx typing/btype.cmx parsing/asttypes.cmi \
     typing/printtyp.cmi
 typing/printtyp.cmi : typing/types.cmi typing/path.cmi \
@@ -370,21 +377,23 @@ typing/typecore.cmo : utils/warnings.cmi typing/typetexp.cmi \
     typing/typedecl.cmi typing/subst.cmi typing/stypes.cmi \
     typing/printtyp.cmi typing/printpat.cmi typing/primitive.cmi \
     typing/predef.cmi typing/path.cmi parsing/parsetree.cmi \
-    typing/parmatch.cmi typing/oprint.cmi utils/misc.cmi \
-    parsing/longident.cmi parsing/location.cmi typing/ident.cmi \
-    typing/env.cmi typing/ctype.cmi typing/cmt_format.cmi utils/clflags.cmi \
-    parsing/builtin_attributes.cmi typing/btype.cmi parsing/asttypes.cmi \
-    parsing/ast_helper.cmi typing/annot.cmi typing/typecore.cmi
+    typing/parmatch.cmi typing/outcometree.cmi typing/oprint.cmi \
+    utils/misc.cmi parsing/longident.cmi parsing/location.cmi \
+    typing/ident.cmi typing/env.cmi typing/ctype.cmi utils/config.cmi \
+    typing/cmt_format.cmi utils/clflags.cmi parsing/builtin_attributes.cmi \
+    typing/btype.cmi parsing/asttypes.cmi parsing/ast_helper.cmi \
+    typing/annot.cmi typing/typecore.cmi
 typing/typecore.cmx : utils/warnings.cmx typing/typetexp.cmx \
     typing/types.cmx typing/typeopt.cmx typing/typedtree.cmx \
     typing/typedecl.cmx typing/subst.cmx typing/stypes.cmx \
     typing/printtyp.cmx typing/printpat.cmx typing/primitive.cmx \
     typing/predef.cmx typing/path.cmx parsing/parsetree.cmi \
-    typing/parmatch.cmx typing/oprint.cmx utils/misc.cmx \
-    parsing/longident.cmx parsing/location.cmx typing/ident.cmx \
-    typing/env.cmx typing/ctype.cmx typing/cmt_format.cmx utils/clflags.cmx \
-    parsing/builtin_attributes.cmx typing/btype.cmx parsing/asttypes.cmi \
-    parsing/ast_helper.cmx typing/annot.cmi typing/typecore.cmi
+    typing/parmatch.cmx typing/outcometree.cmx typing/oprint.cmx \
+    utils/misc.cmx parsing/longident.cmx parsing/location.cmx \
+    typing/ident.cmx typing/env.cmx typing/ctype.cmx utils/config.cmx \
+    typing/cmt_format.cmx utils/clflags.cmx parsing/builtin_attributes.cmx \
+    typing/btype.cmx parsing/asttypes.cmi parsing/ast_helper.cmx \
+    typing/annot.cmi typing/typecore.cmi
 typing/typecore.cmi : typing/types.cmi typing/typedtree.cmi typing/path.cmi \
     parsing/parsetree.cmi parsing/longident.cmi parsing/location.cmi \
     typing/ident.cmi typing/env.cmi parsing/asttypes.cmi typing/annot.cmi
@@ -2176,7 +2185,7 @@ toplevel/genprintval.cmo : typing/types.cmi typing/printtyp.cmi \
     typing/env.cmi typing/datarepr.cmi typing/ctype.cmi typing/btype.cmi \
     toplevel/genprintval.cmi
 toplevel/genprintval.cmx : typing/types.cmx typing/printtyp.cmx \
-    typing/predef.cmx typing/path.cmx typing/outcometree.cmi \
+    typing/predef.cmx typing/path.cmx typing/outcometree.cmx \
     typing/oprint.cmx utils/misc.cmx parsing/longident.cmx typing/ident.cmx \
     typing/env.cmx typing/datarepr.cmx typing/ctype.cmx typing/btype.cmx \
     toplevel/genprintval.cmi
@@ -2214,7 +2223,7 @@ toplevel/opttoploop.cmx : utils/warnings.cmx typing/types.cmx \
     typing/printtyped.cmx typing/printtyp.cmx bytecomp/printlambda.cmx \
     parsing/printast.cmx typing/predef.cmx parsing/pprintast.cmx \
     driver/pparse.cmx typing/path.cmx parsing/parsetree.cmi parsing/parse.cmx \
-    typing/outcometree.cmi typing/oprint.cmx utils/misc.cmx \
+    typing/outcometree.cmx typing/oprint.cmx utils/misc.cmx \
     middle_end/middle_end.cmx parsing/longident.cmx parsing/location.cmx \
     parsing/lexer.cmx bytecomp/lambda.cmx typing/includemod.cmx \
     asmcomp/import_approx.cmx typing/ident.cmx toplevel/genprintval.cmx \
@@ -2278,7 +2287,7 @@ toplevel/toploop.cmx : utils/warnings.cmx typing/typetexp.cmx \
     bytecomp/simplif.cmx typing/printtyped.cmx typing/printtyp.cmx \
     bytecomp/printlambda.cmx bytecomp/printinstr.cmx parsing/printast.cmx \
     typing/predef.cmx parsing/pprintast.cmx driver/pparse.cmx typing/path.cmx \
-    parsing/parsetree.cmi parsing/parse.cmx typing/outcometree.cmi \
+    parsing/parsetree.cmi parsing/parse.cmx typing/outcometree.cmx \
     typing/oprint.cmx utils/misc.cmx bytecomp/meta.cmx parsing/longident.cmx \
     parsing/location.cmx parsing/lexer.cmx typing/includemod.cmx \
     typing/ident.cmx toplevel/genprintval.cmx typing/env.cmx \

Changes

@@ -38,6 +38,10 @@ Working version
 
 ### Compiler user-interface and warnings:
 
+- MPR#7574: highlight differences in type error messages and
+  collapse types larger than an arbitrary limit
+  (Florian Angeletti)
+
 - GPR#1166: In OCAMLPARAM, an alternative separator can be specified as
   first character (instead of comma) in the set ":|; ,"
   (Fabrice Le Fessant)

Makefile

@@ -100,7 +100,7 @@ PARSING=parsing/location.cmo parsing/longident.cmo \
 
 TYPING=typing/ident.cmo typing/path.cmo \
   typing/primitive.cmo typing/types.cmo \
-  typing/btype.cmo typing/oprint.cmo \
+  typing/btype.cmo typing/outcometree.cmo typing/difftree.cmo typing/oprint.cmo \
   typing/subst.cmo typing/predef.cmo \
   typing/datarepr.cmo typing/cmi_format.cmo typing/env.cmo \
   typing/typedtree.cmo typing/printtyped.cmo typing/ctype.cmo \

debugger/Makefile

@@ -49,7 +49,7 @@ OTHEROBJS=\
   ../typing/btype.cmo ../typing/primitive.cmo ../typing/typedtree.cmo \
   ../typing/subst.cmo ../typing/predef.cmo \
   ../typing/datarepr.cmo ../typing/cmi_format.cmo ../typing/env.cmo \
-  ../typing/oprint.cmo \
+  ../typing/outcometree.cmo ../typing/difftree.cmo ../typing/oprint.cmo \
   ../typing/ctype.cmo ../typing/printtyp.cmo ../typing/mtype.cmo \
   ../typing/envaux.cmo \
   ../bytecomp/runtimedef.cmo ../bytecomp/bytesections.cmo \

debugger/printval.ml

@@ -85,13 +85,13 @@ let max_printer_steps = ref 300
 
 let print_exception ppf obj =
   let t = Printer.outval_of_untyped_exception obj in
-  !Oprint.out_value ppf t
+  !Oprint.out_value ppf (Outcometree.Decorate.value t)
 
 let print_value max_depth env obj (ppf : Format.formatter) ty =
   let t =
     Printer.outval_of_value !max_printer_steps max_depth
       check_depth env obj ty in
-  !Oprint.out_value ppf t
+  !Oprint.out_value ppf (Outcometree.Decorate.value t)
 
 let print_named_value max_depth exp env obj ppf ty =
   let print_value_name ppf = function

driver/main.ml

@@ -43,6 +43,7 @@ module Options = Main_args.Make_bytecomp_options (struct
   let _no_check_prims = set no_check_prims
   let _dllib s = defer (ProcessDLLs (Misc.rev_split_words s))
   let _dllpath s = dllpaths := !dllpaths @ [s]
+  let _error_size n = error_size := n
   let _for_pack s = for_package := Some s
   let _g = set debug
   let _i () = print_types := true; compile_only := true
@@ -108,6 +109,7 @@ module Options = Main_args.Make_bytecomp_options (struct
           | None -> ()
           | Some setting -> color := Some setting
     end
+  let _diff_markers = set diff_markers
   let _where = print_standard_library
   let _verbose = set verbose
   let _nopervasives = set nopervasives

driver/main_args.ml

@@ -77,6 +77,12 @@ let mk_dllpath f =
   "<dir>  Add <dir> to the run-time search path for shared libraries"
 ;;
 
+let mk_errorsize i =
+  "-error-size", Arg.Int i,
+  "<size>  Increase the size of error messages to <size> (in arbitrary units),\
+  \     the default size is 12."
+;;
+
 let mk_dtypes f =
   "-dtypes", Arg.Unit f, " (deprecated) same as -annot"
 ;;
@@ -589,6 +595,10 @@ let mk_color f =
   \    not empty or \"dumb\", and that isatty(stderr) holds."
 ;;
 
+let mk_diffmarkers f =
+  "-diff-markers", Arg.Unit f,
+  " Emphasize difference with a prefix marker in type errors."
+
 let mk_where f =
   "-where", Arg.Unit f, " Print location of standard library and exit"
 ;;
@@ -787,6 +797,8 @@ module type Common_options = sig
   val _noassert : unit -> unit
   val _nolabels : unit -> unit
   val _nostdlib : unit -> unit
+  val _diff_markers: unit -> unit
+  val _error_size: int -> unit
   val _open : string -> unit
   val _ppx : string -> unit
   val _principal : unit -> unit
@@ -1012,9 +1024,11 @@ struct
     mk_compat_32 F._compat_32;
     mk_config F._config;
     mk_custom F._custom;
+    mk_diffmarkers F._diff_markers;
     mk_dllib F._dllib;
     mk_dllpath F._dllpath;
     mk_dtypes F._annot;
+    mk_errorsize F._error_size;
     mk_for_pack_byt F._for_pack;
     mk_g_byt F._g;
     mk_i F._i;
@@ -1114,6 +1128,8 @@ struct
     mk_nopromptcont F._nopromptcont;
     mk_nostdlib F._nostdlib;
     mk_open F._open;
+    mk_diffmarkers F._diff_markers;
+    mk_errorsize F._error_size;
     mk_ppx F._ppx;
     mk_principal F._principal;
     mk_no_principal F._no_principal;
@@ -1171,6 +1187,8 @@ struct
     mk_compact F._compact;
     mk_config F._config;
     mk_dtypes F._annot;
+    mk_diffmarkers F._diff_markers;
+    mk_errorsize F._error_size;
     mk_for_pack_opt F._for_pack;
     mk_g_opt F._g;
     mk_i F._i;
@@ -1327,6 +1345,8 @@ module Make_opttop_options (F : Opttop_options) = struct
     mk_o2 F._o2;
     mk_o3 F._o3;
     mk_open F._open;
+    mk_diffmarkers F._diff_markers;
+    mk_errorsize F._error_size;
     mk_ppx F._ppx;
     mk_principal F._principal;
     mk_no_principal F._no_principal;

driver/main_args.mli

@@ -27,6 +27,8 @@ module type Common_options = sig
   val _noassert : unit -> unit
   val _nolabels : unit -> unit
   val _nostdlib : unit -> unit
+  val _diff_markers: unit -> unit
+  val _error_size: int -> unit
   val _open : string -> unit
   val _ppx : string -> unit
   val _principal : unit -> unit

driver/optmain.ml

@@ -58,6 +58,7 @@ module Options = Main_args.Make_optcomp_options (struct
   let _clambda_checks () = clambda_checks := true
   let _compact = clear optimize_for_speed
   let _config () = show_config ()
+  let _error_size n =  error_size := n
   let _for_pack s = for_package := Some s
   let _g = set debug
   let _i () = print_types := true; compile_only := true
@@ -192,6 +193,7 @@ module Options = Main_args.Make_optcomp_options (struct
           | None -> ()
           | Some setting -> color := Some setting
     end
+  let _diff_markers = set diff_markers
   let _where () = print_standard_library ()
 
   let _nopervasives = set nopervasives

man/ocaml.m

@@ -70,6 +70,17 @@
 .B \-absname
 Show absolute filenames in error messages.
 .TP
+.B \-diff-markers
+Use textual markers to highlight differences in error messages
+and do not rely only on color.
+.TP
+.BI \-error-size \ size
+Set the optimal error size for type error messages in arbitrary units.
+The default size is 12, a typical range for this size would be between
+3 and 30.
+Types larger than this error size will be elided in order to fit this
+limit.
+.TP
 .BI \-I \ directory
 Add the given directory to the list of directories searched for
 source and compiled files. By default, the current directory is

man/ocamlc.m

@@ -331,6 +331,10 @@ use heuristics to enable colors only if the output supports them (an
 .BR ocamlrun (1)
 at program start-up time.
 .TP
+.B \-diff-markers
+Use textual markers to highlight differences in error messages
+and do not rely only on color.
+.TP
 .BI \-dllpath \ dir
 Adds the directory
 .I dir
@@ -348,6 +352,13 @@ standard search path (the one corresponding to the
 .BR ocamlrun (1)
 can find it and use it.
 .TP
+.BI \-error-size \ size
+Set the optimal error size for type error messages in arbitrary units.
+The default size is 12, a typical range for this size would be between
+3 and 30.
+Types larger than this error size will be elided in order to fit
+this limit.
+.TP
 .BI \-for\-pack \ module\-path
 Generate an object file (.cmo file) that can later be included
 as a sub-module (with the given access path) of a compilation unit

man/ocamlopt.m

@@ -255,6 +255,17 @@ use heuristics to enable colors only if the output supports them (an
 .BI \-depend\ ocamldep-args
 Compute dependencies, as ocamldep would do.
 .TP
+.B \-diff-markers
+Use textual markers to highlight differences in error messages
+and do not rely only on color.
+.TP
+.BI \-error-size \ size
+Set the optimal error size for type error messages in arbitrary units.
+The default size is 12, a typical range for this size would be between
+3 and 30.
+Types larger than this error size will be elided in order to fit
+this limit.
+.TP
 .BI \-for\-pack \ module\-path
 Generate an object file (.cmx and .o files) that can later be included
 as a sub-module (with the given access path) of a compilation unit

manual/manual/cmds/unified-options.etex

@@ -183,6 +183,11 @@ Compute dependencies, as the "ocamldep" command would do. The remaining
 arguments are interpreted as if they were given to the "ocamldep" command.
 }%notop
 
+
+\item["-diff-marker" \var{size}]
+Use textual markers to highlight differences in error messages
+and do not rely only on color.
+
 \comp{
 \item["-dllib" "-l"\var{libname}]
 Arrange for the C shared library "dll"\var{libname}".so"
@@ -199,6 +204,12 @@ executable file, where "ocamlrun" can find it and use it as
 described in section~\ref{s-ocamlrun-dllpath}.
 }%comp
 
+\item["-error-size" \var{size}]
+Set the optimal error size for type error messages in arbitrary units.
+The default size is 12, a typical range for this size would be between 3
+and 30.
+Types larger than this error size will be elided in order to fit this limit.
+
 \notop{%
 \item["-for-pack" \var{module-path}]
 Generate an object file (\qcmo\nat{ and ".o"/".obj" files})

ocamldoc/odoc_args.ml

@@ -213,6 +213,8 @@ module Options = Main_args.Make_ocamldoc_options(struct
   let _noassert = set Clflags.noassert
   let _nolabels = set Clflags.classic
   let _nostdlib = set Clflags.no_std_include
+  let _diff_markers = set Clflags.diff_markers
+  let _error_size n = Clflags.error_size := n
   let _open s = Clflags.open_modules := s :: !Clflags.open_modules
   let _pp s = Clflags.preprocessor := Some s
   let _ppx s = Clflags.all_ppx := s :: !Clflags.all_ppx