diff --git a/CHANGES b/CHANGES
index a9ab2b497b..7e74e007b5 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,7 @@
+8.0.0-dev.140 | 2025-05-19 11:04:29 -0700
+
+  * Change from_json to return an error rather than print it. (Steve Smoot, Corelight)
+
 8.0.0-dev.136 | 2025-05-19 20:01:30 +0200
 
   * btest/core: Add event-trace test (Arne Welzel, Corelight)
diff --git a/VERSION b/VERSION
index 42d5b5679d..d23b083288 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-8.0.0-dev.136
+8.0.0-dev.140
diff --git a/scripts/base/init-bare.zeek b/scripts/base/init-bare.zeek
index 02d5ab599d..e80262b125 100644
--- a/scripts/base/init-bare.zeek
+++ b/scripts/base/init-bare.zeek
@@ -1491,6 +1491,7 @@ function from_json_default_key_mapper(s: string): string
 type from_json_result: record {
 	v: any &optional;	##< Parsed value.
 	valid: bool;	##< True if parsing was successful.
+	err: string &optional;	## Error string if unsuccessful.
 };
 
 # TCP values for :zeek:see:`endpoint` *state* field.
diff --git a/src/zeek.bif b/src/zeek.bif
index 8702a0a7fa..f21d9fa065 100644
--- a/src/zeek.bif
+++ b/src/zeek.bif
@@ -5240,7 +5240,7 @@ function to_json%(val: any, only_loggable: bool &default=F, field_escape_pattern
 ##           when keys are not valid field identifiers, or represent reserved
 ##           keywords like **port** or **type**.
 ##
-## returns: A value of type t.
+## returns: A record with the result of the conversion, containing either a value or an error message.
 ##
 ## .. zeek:see:: to_json
 function from_json%(s: string, t: any, key_func: string_mapper &default=from_json_default_key_mapper%): from_json_result
@@ -5276,7 +5276,7 @@ function from_json%(s: string, t: any, key_func: string_mapper &default=from_jso
 	else
 		{
 		rval->Assign(valid_idx, false);
-		zeek::emit_builtin_error(res.error().c_str());
+                rval->Assign(result_type->FieldOffset("err"), res.error().c_str());
 		}
 
 	return std::move(rval);
diff --git a/testing/btest/Baseline.zam/bifs.from_json-10/.stdout b/testing/btest/Baseline.zam/bifs.from_json-10/.stdout
index c7202a240c..86d70c20c4 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-10/.stdout
+++ b/testing/btest/Baseline.zam/bifs.from_json-10/.stdout
@@ -2,5 +2,5 @@
 [v={
 fe80::/64,
 192.168.0.0/16
-}, valid=T]
-[v=[1, 3, 4], valid=T]
+}, valid=T, err=<uninitialized>]
+[v=[1, 3, 4], valid=T, err=<uninitialized>]
diff --git a/testing/btest/Baseline.zam/bifs.from_json-11/.stderr b/testing/btest/Baseline.zam/bifs.from_json-11/.stderr
index a94a645929..49d861c74c 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-11/.stderr
+++ b/testing/btest/Baseline.zam/bifs.from_json-11/.stderr
@@ -1,3 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 8: required field Foo$hello is missing in JSON (from_json({"t":null}, <internal>::#0, from_json_default_key_mapper))
-error in <...>/from_json.zeek, line 9: required field Foo$hello is null in JSON (from_json({"hello": null, "t": true}, <internal>::#2, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline.zam/bifs.from_json-11/.stdout b/testing/btest/Baseline.zam/bifs.from_json-11/.stdout
index d288024480..3c683728b9 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-11/.stdout
+++ b/testing/btest/Baseline.zam/bifs.from_json-11/.stdout
@@ -1,3 +1,3 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=required field Foo$hello is missing in JSON]
+[v=<uninitialized>, valid=F, err=required field Foo$hello is null in JSON]
diff --git a/testing/btest/Baseline.zam/bifs.from_json-12/.stdout b/testing/btest/Baseline.zam/bifs.from_json-12/.stdout
index 7673a47ea5..0652f5c2cb 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-12/.stdout
+++ b/testing/btest/Baseline.zam/bifs.from_json-12/.stdout
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=[hello=Hello!], valid=T]
+[v=[hello=Hello!], valid=T, err=<uninitialized>]
diff --git a/testing/btest/Baseline.zam/bifs.from_json-13/.stderr b/testing/btest/Baseline.zam/bifs.from_json-13/.stderr
index ec05b0d535..49d861c74c 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-13/.stderr
+++ b/testing/btest/Baseline.zam/bifs.from_json-13/.stderr
@@ -1,2 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 7: required field Foo$id_field is missing in JSON (from_json({"id-field": "Hello!"}, <internal>::#0, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline.zam/bifs.from_json-13/.stdout b/testing/btest/Baseline.zam/bifs.from_json-13/.stdout
index b75189ee1e..6fe9df1b87 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-13/.stdout
+++ b/testing/btest/Baseline.zam/bifs.from_json-13/.stdout
@@ -1,3 +1,3 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
-[v=[id_field=Hello!], valid=T]
+[v=<uninitialized>, valid=F, err=required field Foo$id_field is missing in JSON]
+[v=[id_field=Hello!], valid=T, err=<uninitialized>]
diff --git a/testing/btest/Baseline.zam/bifs.from_json-2/.stdout b/testing/btest/Baseline.zam/bifs.from_json-2/.stdout
index aee95c8a8e..5748f09000 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-2/.stdout
+++ b/testing/btest/Baseline.zam/bifs.from_json-2/.stdout
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=<uninitialized>]
diff --git a/testing/btest/Baseline.zam/bifs.from_json-3/.stderr b/testing/btest/Baseline.zam/bifs.from_json-3/.stderr
index 233c4318e1..49d861c74c 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-3/.stderr
+++ b/testing/btest/Baseline.zam/bifs.from_json-3/.stderr
@@ -1,2 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 4: JSON parse error: Missing a closing quotation mark in string. Offset: 5 (from_json({"hel, <internal>::#0, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline.zam/bifs.from_json-3/.stdout b/testing/btest/Baseline.zam/bifs.from_json-3/.stdout
index aee95c8a8e..4c74a75e27 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-3/.stdout
+++ b/testing/btest/Baseline.zam/bifs.from_json-3/.stdout
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=JSON parse error: Missing a closing quotation mark in string. Offset: 5]
diff --git a/testing/btest/Baseline.zam/bifs.from_json-4/.stderr b/testing/btest/Baseline.zam/bifs.from_json-4/.stderr
index 42e6dad6f0..49d861c74c 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-4/.stderr
+++ b/testing/btest/Baseline.zam/bifs.from_json-4/.stderr
@@ -1,3 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 9: cannot convert JSON type 'array' to Zeek type 'bool' (from_json([], <internal>::#0, from_json_default_key_mapper))
-error in <...>/from_json.zeek, line 10: cannot convert JSON type 'string' to Zeek type 'bool' (from_json({"a": "hello"}, <internal>::#2, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline.zam/bifs.from_json-4/.stdout b/testing/btest/Baseline.zam/bifs.from_json-4/.stdout
index d288024480..fc1ece90e4 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-4/.stdout
+++ b/testing/btest/Baseline.zam/bifs.from_json-4/.stdout
@@ -1,3 +1,3 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=cannot convert JSON type 'array' to Zeek type 'bool']
+[v=<uninitialized>, valid=F, err=cannot convert JSON type 'string' to Zeek type 'bool']
diff --git a/testing/btest/Baseline.zam/bifs.from_json-5/.stderr b/testing/btest/Baseline.zam/bifs.from_json-5/.stderr
index d7ed338df6..49d861c74c 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-5/.stderr
+++ b/testing/btest/Baseline.zam/bifs.from_json-5/.stderr
@@ -1,2 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 4: cannot convert JSON type 'array' to Zeek type 'table' (from_json([], <internal>::#0, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline.zam/bifs.from_json-5/.stdout b/testing/btest/Baseline.zam/bifs.from_json-5/.stdout
index aee95c8a8e..9f17c6908a 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-5/.stdout
+++ b/testing/btest/Baseline.zam/bifs.from_json-5/.stdout
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=cannot convert JSON type 'array' to Zeek type 'table']
diff --git a/testing/btest/Baseline.zam/bifs.from_json-6/.stderr b/testing/btest/Baseline.zam/bifs.from_json-6/.stderr
index b1ddbdd07a..49d861c74c 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-6/.stderr
+++ b/testing/btest/Baseline.zam/bifs.from_json-6/.stderr
@@ -1,3 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 8: wrong port format, string must be <...>/(tcp|udp|icmp|unknown)/ (from_json("80", <internal>::#2, from_json_default_key_mapper))
-error in <...>/from_json.zeek, line 9: wrong port format, object must have 'port' and 'proto' members (from_json({}, <internal>::#4, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline.zam/bifs.from_json-6/.stdout b/testing/btest/Baseline.zam/bifs.from_json-6/.stdout
index a4da3aa3e4..67881cd4d2 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-6/.stdout
+++ b/testing/btest/Baseline.zam/bifs.from_json-6/.stdout
@@ -1,4 +1,4 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=80/tcp, valid=T]
-[v=<uninitialized>, valid=F]
-[v=<uninitialized>, valid=F]
+[v=80/tcp, valid=T, err=<uninitialized>]
+[v=<uninitialized>, valid=F, err=wrong port format, string must be /[0-9]{1,5}\/(tcp|udp|icmp|unknown)/]
+[v=<uninitialized>, valid=F, err=wrong port format, object must have 'port' and 'proto' members]
diff --git a/testing/btest/Baseline.zam/bifs.from_json-7/.stderr b/testing/btest/Baseline.zam/bifs.from_json-7/.stderr
index 315336902b..49d861c74c 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-7/.stderr
+++ b/testing/btest/Baseline.zam/bifs.from_json-7/.stderr
@@ -1,3 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 5: index type doesn't match (from_json([[1, false], [2]], <internal>::#0, from_json_default_key_mapper))
-error in <...>/from_json.zeek, line 6: cannot convert JSON type 'number' to Zeek type 'bool' (from_json([[1, false], [2, 1]], <internal>::#2, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline.zam/bifs.from_json-7/.stdout b/testing/btest/Baseline.zam/bifs.from_json-7/.stdout
index d288024480..6ea7385db5 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-7/.stdout
+++ b/testing/btest/Baseline.zam/bifs.from_json-7/.stdout
@@ -1,3 +1,3 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=index type doesn't match]
+[v=<uninitialized>, valid=F, err=cannot convert JSON type 'number' to Zeek type 'bool']
diff --git a/testing/btest/Baseline.zam/bifs.from_json-8/.stderr b/testing/btest/Baseline.zam/bifs.from_json-8/.stderr
index 6c89085ca4..e0f6cb3d5d 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-8/.stderr
+++ b/testing/btest/Baseline.zam/bifs.from_json-8/.stderr
@@ -1,3 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
 error: error compiling pattern /^?(.|\n)*(([[:print:]]{-}[[:alnum:]]foo))/
-error in <...>/from_json.zeek, line 5: error compiling pattern (from_json("/([[:print:]]{-}[[:alnum:]]foo)/", <internal>::#0, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline.zam/bifs.from_json-8/.stdout b/testing/btest/Baseline.zam/bifs.from_json-8/.stdout
index aee95c8a8e..0bd6d65b29 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-8/.stdout
+++ b/testing/btest/Baseline.zam/bifs.from_json-8/.stdout
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=error compiling pattern]
diff --git a/testing/btest/Baseline.zam/bifs.from_json-9/.stderr b/testing/btest/Baseline.zam/bifs.from_json-9/.stderr
index 7ff4fdd21e..49d861c74c 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-9/.stderr
+++ b/testing/btest/Baseline.zam/bifs.from_json-9/.stderr
@@ -1,2 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 7: 'Yellow' is not a valid enum for 'Color'. (from_json("Yellow", <internal>::#0, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline.zam/bifs.from_json-9/.stdout b/testing/btest/Baseline.zam/bifs.from_json-9/.stdout
index aee95c8a8e..6dd6561c32 100644
--- a/testing/btest/Baseline.zam/bifs.from_json-9/.stdout
+++ b/testing/btest/Baseline.zam/bifs.from_json-9/.stdout
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err='Yellow' is not a valid enum for 'Color'.]
diff --git a/testing/btest/Baseline.zam/bifs.from_json/.stdout b/testing/btest/Baseline.zam/bifs.from_json/.stdout
index 584cb2ca60..c2a28513ec 100644
--- a/testing/btest/Baseline.zam/bifs.from_json/.stdout
+++ b/testing/btest/Baseline.zam/bifs.from_json/.stdout
@@ -7,4 +7,4 @@ aa:bb::/32,
 [2001:db8::1, 8080/udp] 
 }, tbl={
 [192.168.0.1, 80/tcp] = foo
-}], valid=T]
+}], valid=T, err=<uninitialized>]
diff --git a/testing/btest/Baseline/bifs.from_json-10/.stdout b/testing/btest/Baseline/bifs.from_json-10/.stdout
index c7202a240c..86d70c20c4 100644
--- a/testing/btest/Baseline/bifs.from_json-10/.stdout
+++ b/testing/btest/Baseline/bifs.from_json-10/.stdout
@@ -2,5 +2,5 @@
 [v={
 fe80::/64,
 192.168.0.0/16
-}, valid=T]
-[v=[1, 3, 4], valid=T]
+}, valid=T, err=<uninitialized>]
+[v=[1, 3, 4], valid=T, err=<uninitialized>]
diff --git a/testing/btest/Baseline/bifs.from_json-11/.stderr b/testing/btest/Baseline/bifs.from_json-11/.stderr
index f55d851395..49d861c74c 100644
--- a/testing/btest/Baseline/bifs.from_json-11/.stderr
+++ b/testing/btest/Baseline/bifs.from_json-11/.stderr
@@ -1,3 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 8: required field Foo$hello is missing in JSON (from_json({"t":null}, to_any_coerce Foo, from_json_default_key_mapper))
-error in <...>/from_json.zeek, line 9: required field Foo$hello is null in JSON (from_json({"hello": null, "t": true}, to_any_coerce Foo, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline/bifs.from_json-11/.stdout b/testing/btest/Baseline/bifs.from_json-11/.stdout
index d288024480..3c683728b9 100644
--- a/testing/btest/Baseline/bifs.from_json-11/.stdout
+++ b/testing/btest/Baseline/bifs.from_json-11/.stdout
@@ -1,3 +1,3 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=required field Foo$hello is missing in JSON]
+[v=<uninitialized>, valid=F, err=required field Foo$hello is null in JSON]
diff --git a/testing/btest/Baseline/bifs.from_json-12/.stdout b/testing/btest/Baseline/bifs.from_json-12/.stdout
index 7673a47ea5..0652f5c2cb 100644
--- a/testing/btest/Baseline/bifs.from_json-12/.stdout
+++ b/testing/btest/Baseline/bifs.from_json-12/.stdout
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=[hello=Hello!], valid=T]
+[v=[hello=Hello!], valid=T, err=<uninitialized>]
diff --git a/testing/btest/Baseline/bifs.from_json-13/.stderr b/testing/btest/Baseline/bifs.from_json-13/.stderr
index bcd3488ad0..49d861c74c 100644
--- a/testing/btest/Baseline/bifs.from_json-13/.stderr
+++ b/testing/btest/Baseline/bifs.from_json-13/.stderr
@@ -1,2 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 7: required field Foo$id_field is missing in JSON (from_json({"id-field": "Hello!"}, to_any_coerce Foo, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline/bifs.from_json-13/.stdout b/testing/btest/Baseline/bifs.from_json-13/.stdout
index b75189ee1e..6fe9df1b87 100644
--- a/testing/btest/Baseline/bifs.from_json-13/.stdout
+++ b/testing/btest/Baseline/bifs.from_json-13/.stdout
@@ -1,3 +1,3 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
-[v=[id_field=Hello!], valid=T]
+[v=<uninitialized>, valid=F, err=required field Foo$id_field is missing in JSON]
+[v=[id_field=Hello!], valid=T, err=<uninitialized>]
diff --git a/testing/btest/Baseline/bifs.from_json-2/.stdout b/testing/btest/Baseline/bifs.from_json-2/.stdout
index aee95c8a8e..5748f09000 100644
--- a/testing/btest/Baseline/bifs.from_json-2/.stdout
+++ b/testing/btest/Baseline/bifs.from_json-2/.stdout
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=<uninitialized>]
diff --git a/testing/btest/Baseline/bifs.from_json-3/.stderr b/testing/btest/Baseline/bifs.from_json-3/.stderr
index 57ad3dca82..49d861c74c 100644
--- a/testing/btest/Baseline/bifs.from_json-3/.stderr
+++ b/testing/btest/Baseline/bifs.from_json-3/.stderr
@@ -1,2 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 4: JSON parse error: Missing a closing quotation mark in string. Offset: 5 (from_json({"hel, to_any_coerce string_vec, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline/bifs.from_json-3/.stdout b/testing/btest/Baseline/bifs.from_json-3/.stdout
index aee95c8a8e..4c74a75e27 100644
--- a/testing/btest/Baseline/bifs.from_json-3/.stdout
+++ b/testing/btest/Baseline/bifs.from_json-3/.stdout
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=JSON parse error: Missing a closing quotation mark in string. Offset: 5]
diff --git a/testing/btest/Baseline/bifs.from_json-4/.stderr b/testing/btest/Baseline/bifs.from_json-4/.stderr
index d2fdc4565c..49d861c74c 100644
--- a/testing/btest/Baseline/bifs.from_json-4/.stderr
+++ b/testing/btest/Baseline/bifs.from_json-4/.stderr
@@ -1,3 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 9: cannot convert JSON type 'array' to Zeek type 'bool' (from_json([], to_any_coerce bool_t, from_json_default_key_mapper))
-error in <...>/from_json.zeek, line 10: cannot convert JSON type 'string' to Zeek type 'bool' (from_json({"a": "hello"}, to_any_coerce Foo, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline/bifs.from_json-4/.stdout b/testing/btest/Baseline/bifs.from_json-4/.stdout
index d288024480..fc1ece90e4 100644
--- a/testing/btest/Baseline/bifs.from_json-4/.stdout
+++ b/testing/btest/Baseline/bifs.from_json-4/.stdout
@@ -1,3 +1,3 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=cannot convert JSON type 'array' to Zeek type 'bool']
+[v=<uninitialized>, valid=F, err=cannot convert JSON type 'string' to Zeek type 'bool']
diff --git a/testing/btest/Baseline/bifs.from_json-5/.stderr b/testing/btest/Baseline/bifs.from_json-5/.stderr
index 6bdd60e118..49d861c74c 100644
--- a/testing/btest/Baseline/bifs.from_json-5/.stderr
+++ b/testing/btest/Baseline/bifs.from_json-5/.stderr
@@ -1,2 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 4: cannot convert JSON type 'array' to Zeek type 'table' (from_json([], to_any_coerce table_string_of_string, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline/bifs.from_json-5/.stdout b/testing/btest/Baseline/bifs.from_json-5/.stdout
index aee95c8a8e..9f17c6908a 100644
--- a/testing/btest/Baseline/bifs.from_json-5/.stdout
+++ b/testing/btest/Baseline/bifs.from_json-5/.stdout
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=cannot convert JSON type 'array' to Zeek type 'table']
diff --git a/testing/btest/Baseline/bifs.from_json-6/.stderr b/testing/btest/Baseline/bifs.from_json-6/.stderr
index 0b278db5ae..49d861c74c 100644
--- a/testing/btest/Baseline/bifs.from_json-6/.stderr
+++ b/testing/btest/Baseline/bifs.from_json-6/.stderr
@@ -1,3 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 8: wrong port format, string must be <...>/(tcp|udp|icmp|unknown)/ (from_json("80", to_any_coerce port_t, from_json_default_key_mapper))
-error in <...>/from_json.zeek, line 9: wrong port format, object must have 'port' and 'proto' members (from_json({}, to_any_coerce port_t, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline/bifs.from_json-6/.stdout b/testing/btest/Baseline/bifs.from_json-6/.stdout
index a4da3aa3e4..67881cd4d2 100644
--- a/testing/btest/Baseline/bifs.from_json-6/.stdout
+++ b/testing/btest/Baseline/bifs.from_json-6/.stdout
@@ -1,4 +1,4 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=80/tcp, valid=T]
-[v=<uninitialized>, valid=F]
-[v=<uninitialized>, valid=F]
+[v=80/tcp, valid=T, err=<uninitialized>]
+[v=<uninitialized>, valid=F, err=wrong port format, string must be /[0-9]{1,5}\/(tcp|udp|icmp|unknown)/]
+[v=<uninitialized>, valid=F, err=wrong port format, object must have 'port' and 'proto' members]
diff --git a/testing/btest/Baseline/bifs.from_json-7/.stderr b/testing/btest/Baseline/bifs.from_json-7/.stderr
index d4c3adfdaf..49d861c74c 100644
--- a/testing/btest/Baseline/bifs.from_json-7/.stderr
+++ b/testing/btest/Baseline/bifs.from_json-7/.stderr
@@ -1,3 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 5: index type doesn't match (from_json([[1, false], [2]], to_any_coerce set_t, from_json_default_key_mapper))
-error in <...>/from_json.zeek, line 6: cannot convert JSON type 'number' to Zeek type 'bool' (from_json([[1, false], [2, 1]], to_any_coerce set_t, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline/bifs.from_json-7/.stdout b/testing/btest/Baseline/bifs.from_json-7/.stdout
index d288024480..6ea7385db5 100644
--- a/testing/btest/Baseline/bifs.from_json-7/.stdout
+++ b/testing/btest/Baseline/bifs.from_json-7/.stdout
@@ -1,3 +1,3 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=index type doesn't match]
+[v=<uninitialized>, valid=F, err=cannot convert JSON type 'number' to Zeek type 'bool']
diff --git a/testing/btest/Baseline/bifs.from_json-8/.stderr b/testing/btest/Baseline/bifs.from_json-8/.stderr
index d7d70be9e8..e0f6cb3d5d 100644
--- a/testing/btest/Baseline/bifs.from_json-8/.stderr
+++ b/testing/btest/Baseline/bifs.from_json-8/.stderr
@@ -1,3 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
 error: error compiling pattern /^?(.|\n)*(([[:print:]]{-}[[:alnum:]]foo))/
-error in <...>/from_json.zeek, line 5: error compiling pattern (from_json("/([[:print:]]{-}[[:alnum:]]foo)/", to_any_coerce pattern_t, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline/bifs.from_json-8/.stdout b/testing/btest/Baseline/bifs.from_json-8/.stdout
index aee95c8a8e..0bd6d65b29 100644
--- a/testing/btest/Baseline/bifs.from_json-8/.stdout
+++ b/testing/btest/Baseline/bifs.from_json-8/.stdout
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err=error compiling pattern]
diff --git a/testing/btest/Baseline/bifs.from_json-9/.stderr b/testing/btest/Baseline/bifs.from_json-9/.stderr
index 92f3d9ea84..49d861c74c 100644
--- a/testing/btest/Baseline/bifs.from_json-9/.stderr
+++ b/testing/btest/Baseline/bifs.from_json-9/.stderr
@@ -1,2 +1 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-error in <...>/from_json.zeek, line 7: 'Yellow' is not a valid enum for 'Color'. (from_json("Yellow", to_any_coerce Color, from_json_default_key_mapper))
diff --git a/testing/btest/Baseline/bifs.from_json-9/.stdout b/testing/btest/Baseline/bifs.from_json-9/.stdout
index aee95c8a8e..6dd6561c32 100644
--- a/testing/btest/Baseline/bifs.from_json-9/.stdout
+++ b/testing/btest/Baseline/bifs.from_json-9/.stdout
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=<uninitialized>, valid=F]
+[v=<uninitialized>, valid=F, err='Yellow' is not a valid enum for 'Color'.]
diff --git a/testing/btest/Baseline/bifs.from_json/.stdout b/testing/btest/Baseline/bifs.from_json/.stdout
index 584cb2ca60..c2a28513ec 100644
--- a/testing/btest/Baseline/bifs.from_json/.stdout
+++ b/testing/btest/Baseline/bifs.from_json/.stdout
@@ -7,4 +7,4 @@ aa:bb::/32,
 [2001:db8::1, 8080/udp] 
 }, tbl={
 [192.168.0.1, 80/tcp] = foo
-}], valid=T]
+}], valid=T, err=<uninitialized>]
diff --git a/testing/btest/Baseline/language.type-expr/.stdout b/testing/btest/Baseline/language.type-expr/.stdout
index 9202868d09..d8c7e4150b 100644
--- a/testing/btest/Baseline/language.type-expr/.stdout
+++ b/testing/btest/Baseline/language.type-expr/.stdout
@@ -1,5 +1,5 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-[v=aoeu, valid=T]
+[v=aoeu, valid=T, err=<uninitialized>]
 type
 double
 vector of int