From f783f33c758f8e40c2394aaaa26505f8b1d75824 Mon Sep 17 00:00:00 2001
From: nojaf <florian.verdonck@outlook.com>
Date: Thu, 1 Sep 2022 15:16:53 +0200
Subject: [PATCH] Add extra space when first type argument is a statically
 resolved type parameter.

---
 src/Compiler/Checking/NicePrint.fs            | 17 ++++--
 .../FSharp.Compiler.ComponentTests.fsproj     |  1 +
 .../Signatures/RecordTests.fs                 |  2 +-
 .../StaticallyResolvedTypeParameterTests.fs   | 53 +++++++++++++++++++
 tests/FSharp.Test.Utilities/Compiler.fs       |  2 +-
 5 files changed, 70 insertions(+), 5 deletions(-)
 create mode 100644 tests/FSharp.Compiler.ComponentTests/Signatures/StaticallyResolvedTypeParameterTests.fs

diff --git a/src/Compiler/Checking/NicePrint.fs b/src/Compiler/Checking/NicePrint.fs
index 3913253a0e..938d2982fa 100644
--- a/src/Compiler/Checking/NicePrint.fs
+++ b/src/Compiler/Checking/NicePrint.fs
@@ -862,11 +862,22 @@ module PrintTypes =
 
     /// Layout type arguments, either NAME<ty, ..., ty> or (ty, ..., ty) NAME *)
     and layoutTypeAppWithInfoAndPrec denv env tcL prec prefix argTys =
-        if prefix then 
+        if prefix then
+            let addExtraSpace argTy =
+                match argTy with
+                | TType_var(typar, _) when typar.StaticReq = TyparStaticReq.HeadType -> SepL.space
+                | _ -> emptyL
+
             match argTys with
             | [] -> tcL
-            | [argTy] -> tcL ^^ sepL (tagPunctuation "<") ^^ (layoutTypeWithInfoAndPrec denv env 4 argTy) ^^ rightL (tagPunctuation">")
-            | _ -> bracketIfL (prec <= 1) (tcL ^^ angleL (layoutTypesWithInfoAndPrec denv env 2 (sepL (tagPunctuation ",")) argTys))
+            | [argTy] ->
+                tcL
+                ^^ sepL (tagPunctuation "<")
+                ^^ addExtraSpace argTy
+                ^^ (layoutTypeWithInfoAndPrec denv env 4 argTy)
+                ^^ rightL (tagPunctuation">")
+            | firstArgTy :: _ ->
+                bracketIfL (prec <= 1) (tcL ^^ angleL (addExtraSpace firstArgTy ^^ layoutTypesWithInfoAndPrec denv env 2 (sepL (tagPunctuation ",")) argTys))
         else
             match argTys with
             | [] -> tcL
diff --git a/tests/FSharp.Compiler.ComponentTests/FSharp.Compiler.ComponentTests.fsproj b/tests/FSharp.Compiler.ComponentTests/FSharp.Compiler.ComponentTests.fsproj
index d8bd7df90c..5dace5060a 100644
--- a/tests/FSharp.Compiler.ComponentTests/FSharp.Compiler.ComponentTests.fsproj
+++ b/tests/FSharp.Compiler.ComponentTests/FSharp.Compiler.ComponentTests.fsproj
@@ -199,6 +199,7 @@
     <Compile Include="Signatures\TestHelpers.fs" />
     <Compile Include="Signatures\ModuleOrNamespaceTests.fs" />
     <Compile Include="Signatures\RecordTests.fs" />
+    <Compile Include="Signatures\StaticallyResolvedTypeParameterTests.fs" />
   </ItemGroup>
   <ItemGroup>
     <Content Include="resources\**" CopyToOutputDirectory="Never" CopyToPublishDirectory="PreserveNewest" />
diff --git a/tests/FSharp.Compiler.ComponentTests/Signatures/RecordTests.fs b/tests/FSharp.Compiler.ComponentTests/Signatures/RecordTests.fs
index e51da66215..1d78be1cfb 100644
--- a/tests/FSharp.Compiler.ComponentTests/Signatures/RecordTests.fs
+++ b/tests/FSharp.Compiler.ComponentTests/Signatures/RecordTests.fs
@@ -18,7 +18,7 @@ type PullActions =
             Log : int
         }
 """
-    |> printSignaturesWith 80
+    |> printSignaturesWithPageWidth 80
     |> should
         equal
         """
diff --git a/tests/FSharp.Compiler.ComponentTests/Signatures/StaticallyResolvedTypeParameterTests.fs b/tests/FSharp.Compiler.ComponentTests/Signatures/StaticallyResolvedTypeParameterTests.fs
new file mode 100644
index 0000000000..261d47cf89
--- /dev/null
+++ b/tests/FSharp.Compiler.ComponentTests/Signatures/StaticallyResolvedTypeParameterTests.fs
@@ -0,0 +1,53 @@
+module FSharp.Compiler.ComponentTests.Signatures.StaticallyResolvedTypeParameterTests
+
+open Xunit
+open FsUnit
+open FSharp.Test.Compiler
+open FSharp.Compiler.ComponentTests.Signatures.TestHelpers
+
+[<Fact>]
+let ``Generic function with constraint`` () =
+    FSharp
+        """
+module MyApp.GoodStuff
+
+let inline toString< ^revision when ^revision: (static member GetCommitHash: ^revision -> string)>
+    (p: System.Threading.Tasks.Task< ^revision >)
+    : string =
+    ""
+"""
+    |> printSignaturesWithPageWidth 80
+    |> should
+        equal
+        """
+module MyApp.GoodStuff
+
+val inline toString:
+  p: System.Threading.Tasks.Task< ^revision> -> string
+    when ^revision: (static member GetCommitHash: ^revision -> string)"""
+
+[<Fact>]
+let ``Multiple constraints parameters in type definition`` () =
+    FSharp
+        """
+module Foo
+
+type Meh<'g, 'f> =
+    class 
+    end
+
+let inline toString< ^revision>
+    (p: Meh< ^revision, ^revision>)
+    : string =
+    ""
+"""
+    |> printSignaturesWithPageWidth 80
+    |> should
+        equal
+        """
+module Foo
+
+type Meh<'g,'f> =
+  class end
+
+val inline toString: p: Meh< ^revision,^revision> -> string"""
diff --git a/tests/FSharp.Test.Utilities/Compiler.fs b/tests/FSharp.Test.Utilities/Compiler.fs
index 2d24d2f678..2ce1fc6793 100644
--- a/tests/FSharp.Test.Utilities/Compiler.fs
+++ b/tests/FSharp.Test.Utilities/Compiler.fs
@@ -1342,4 +1342,4 @@ module rec Compiler =
             |> String.concat "\n"
     
     let printSignatures cUnit = printSignaturesImpl None cUnit
-    let printSignaturesWith pageWidth cUnit = printSignaturesImpl (Some pageWidth) cUnit
+    let printSignaturesWithPageWidth pageWidth cUnit = printSignaturesImpl (Some pageWidth) cUnit