diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7b60030..f60ecb6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,8 @@ The `Unreleased` section name is replaced by the expected version of next releas
### Removed
### Fixed
+- Clarify `StreamName.parse` exception message [#58](https://github.com/jet/FsCodec/pull/58) :pray: [@dharmaturtle](https://github.com/dharmaturtle)
+
## [2.1.1] - 2020-05-25
diff --git a/src/FsCodec/StreamName.fs b/src/FsCodec/StreamName.fs
index 5cf3bcc..b84147b 100755
--- a/src/FsCodec/StreamName.fs
+++ b/src/FsCodec/StreamName.fs
@@ -44,7 +44,7 @@ module StreamName =
/// Throws InvalidArgumentException if it does not adhere to that form
let parse (rawStreamName : string) : StreamName =
if rawStreamName.IndexOf('-') = -1 then
- invalidArg (sprintf "Stream Name '%s' must contain a '-' separator" rawStreamName) "streamName"
+ invalidArg "streamName" (sprintf "Stream Name '%s' must contain a '-' separator" rawStreamName)
UMX.tag rawStreamName
(* Parsing: Raw Stream name Validation functions/pattern that handle malformed cases without throwing *)
diff --git a/tests/FsCodec.NewtonsoftJson.Tests/FsCodec.NewtonsoftJson.Tests.fsproj b/tests/FsCodec.NewtonsoftJson.Tests/FsCodec.NewtonsoftJson.Tests.fsproj
index 2b47579..e032670 100644
--- a/tests/FsCodec.NewtonsoftJson.Tests/FsCodec.NewtonsoftJson.Tests.fsproj
+++ b/tests/FsCodec.NewtonsoftJson.Tests/FsCodec.NewtonsoftJson.Tests.fsproj
@@ -15,13 +15,13 @@
-
-
+
+
-
+
diff --git a/tests/FsCodec.SystemTextJson.Tests/FsCodec.SystemTextJson.Tests.fsproj b/tests/FsCodec.SystemTextJson.Tests/FsCodec.SystemTextJson.Tests.fsproj
index 25fabfd..d4d5480 100644
--- a/tests/FsCodec.SystemTextJson.Tests/FsCodec.SystemTextJson.Tests.fsproj
+++ b/tests/FsCodec.SystemTextJson.Tests/FsCodec.SystemTextJson.Tests.fsproj
@@ -7,13 +7,13 @@
-
+
-
+
-
+
diff --git a/tests/FsCodec.Tests/FsCodec.Tests.fsproj b/tests/FsCodec.Tests/FsCodec.Tests.fsproj
index 9725e04..cef43dd 100644
--- a/tests/FsCodec.Tests/FsCodec.Tests.fsproj
+++ b/tests/FsCodec.Tests/FsCodec.Tests.fsproj
@@ -11,10 +11,10 @@
-
+
-
+
diff --git a/tests/FsCodec.Tests/StreamNameTests.fs b/tests/FsCodec.Tests/StreamNameTests.fs
index 373481f..6eaaac7 100644
--- a/tests/FsCodec.Tests/StreamNameTests.fs
+++ b/tests/FsCodec.Tests/StreamNameTests.fs
@@ -30,7 +30,8 @@ let [] ``Can roundtrip single aggregateIds with embedded dashes and unders
test <@ let (StreamName.CategoryAndIds (scat, aggIds)) = sn
scat = cat && ["a-b";"c-d"] = List.ofArray aggIds @>
-let [] ``StreamName.parse throws given 0 separators`` () =
- raisesWith
- <@ StreamName.parse "Cat" @>
- (fun e -> <@ e.Message = "streamName (Parameter 'Stream Name 'Cat' must contain a '-' separator')" @>)
+let [] ``StreamName parse throws given 0 separators`` () =
+ raisesWith <@ StreamName.parse "Cat" @>
+ (fun (e : System.ArgumentException) -> <@
+ e.ParamName = "streamName"
+ && e.Message.StartsWith "Stream Name 'Cat' must contain a '-' separator" @>)