asn1ct_check: Clean up error checking for INSTANCE OF

This will also eliminate a dialyzer warning for unmatched returns,
and increase the coverage.

3 files changed, 37 insertions, 15 deletions

diff --git a/lib/asn1/src/asn1ct_check.erl b/lib/asn1/src/asn1ct_check.erl
index 18275b57a4..c20395aaeb 100644
--- a/lib/asn1/src/asn1ct_check.erl
+++ b/lib/asn1/src/asn1ct_check.erl
@@ -4959,20 +4959,16 @@ check_instance_of(S,DefinedObjectClass,Constraint) ->
     check_type_identifier(S,DefinedObjectClass),
     iof_associated_type(S,Constraint).
     
-
-check_type_identifier(_S,'TYPE-IDENTIFIER') ->
-    ok;
-check_type_identifier(S,Eref=#'Externaltypereference'{}) ->
-    case get_referenced_type(S,Eref) of
-	{_,#classdef{name='TYPE-IDENTIFIER'}} -> ok;
-	{_,#classdef{typespec=NextEref}} 
-	when is_record(NextEref,'Externaltypereference') ->
-	    check_type_identifier(S,NextEref);
+check_type_identifier(S, Eref=#'Externaltypereference'{type=Class}) ->
+    case get_referenced_type(S, Eref) of
+	{_,#classdef{name='TYPE-IDENTIFIER'}} ->
+	    ok;
+	{_,#classdef{typespec=#'Externaltypereference'{}=NextEref}} ->
+	    check_type_identifier(S, NextEref);
 	{_,TD=#typedef{typespec=#type{def=#'Externaltypereference'{}}}} ->
-	    check_type_identifier(S,(TD#typedef.typespec)#type.def);
-	Err ->
-	    error({type,{"object set in type INSTANCE OF "
-			 "not of class TYPE-IDENTIFIER",Eref,Err},S})
+	    check_type_identifier(S, (TD#typedef.typespec)#type.def);
+	_ ->
+	    asn1_error(S, S#state.type, {illegal_instance_of,Class})
     end.
 
 iof_associated_type(S,[]) ->
@@ -6774,6 +6770,10 @@ asn1_error(S, Item, Error) ->
 format_error({already_defined,Name,PrevLine}) ->
     io_lib:format("the name ~p has already been defined at line ~p",
 		  [Name,PrevLine]);
+format_error({illegal_instance_of,Class}) ->
+    io_lib:format("using INSTANCE OF on class '~s' is illegal, "
+		  "because INSTANCE OF may only be used on the class TYPE-IDENTFIER",
+		  [Class]);
 format_error(illegal_octet_string_value) ->
     "expecting a bstring or an hstring as value for an OCTET STRING";
 format_error({invalid_fields,Fields,Obj}) ->
diff --git a/lib/asn1/test/asn1_SUITE_data/INSTANCEOF.asn1 b/lib/asn1/test/asn1_SUITE_data/INSTANCEOF.asn1
index 8c4f3a8f7e..b4ea943040 100644
--- a/lib/asn1/test/asn1_SUITE_data/INSTANCEOF.asn1
+++ b/lib/asn1/test/asn1_SUITE_data/INSTANCEOF.asn1
@@ -16,7 +16,9 @@ Names ::= SEQUENCE {
   thirdName  [2] INSTANCE OF OTHER-NAME ({TI})
 }
 
-OTHER-NAME ::= TYPE-IDENTIFIER
+OTHER-NAME ::= YET-ANOTHER-NAME
+
+YET-ANOTHER-NAME ::= TYPE-IDENTIFIER
 
 TI OTHER-NAME ::= {{INTEGER IDENTIFIED BY {2 4}} |
 		   {Seq IDENTIFIED BY {2 3 4}} |
diff --git a/lib/asn1/test/error_SUITE.erl b/lib/asn1/test/error_SUITE.erl
index 2e4863301f..09327f6e12 100644
--- a/lib/asn1/test/error_SUITE.erl
+++ b/lib/asn1/test/error_SUITE.erl
@@ -19,7 +19,8 @@
 
 -module(error_SUITE).
 -export([suite/0,all/0,groups/0,
-	 already_defined/1,bitstrings/1,enumerated/1,integers/1,objects/1,values/1]).
+	 already_defined/1,bitstrings/1,enumerated/1,
+	 instance_of/1,integers/1,objects/1,values/1]).
 
 -include_lib("test_server/include/test_server.hrl").
 
@@ -33,6 +34,7 @@ groups() ->
       [already_defined,
        bitstrings,
        enumerated,
+       instance_of,
        integers,
        objects,
        values]}].
@@ -117,6 +119,23 @@ enumerated(Config) ->
     } = run(P, Config),
     ok.
 
+instance_of(Config) ->
+    M = 'InstanceOf',
+    P = {M,
+	 <<"InstanceOf DEFINITIONS AUTOMATIC TAGS ::= BEGIN\n"
+	   "XX ::= INSTANCE OF CL ({TI})\n"
+	   "CL ::= CLASS {\n"
+           "&id INTEGER,\n"
+           "&Type\n"
+	   "}\n"
+	   "o1 CL ::= {&id 1, &Type OCTET STRING}\n"
+	   "TI CL ::= { o1 }\n"
+	   "END\n">>},
+    {error,
+     [{structured_error,{M,2},asn1ct_check,{illegal_instance_of,'CL'}}
+     ]} = run(P, Config),
+    ok.
+
 integers(Config) ->
     M = 'Integers',
     P = {M,
@@ -132,6 +151,7 @@ integers(Config) ->
      ]} = run(P, Config),
     ok.
 
+
 objects(Config) ->
     M = 'Objects',
     P = {M,