From 76ec1e5a6f643b2416dc61bbd3f7b8b65863393c Mon Sep 17 00:00:00 2001
From: Patrick Stapfer <ryyppy@users.noreply.github.com>
Date: Wed, 26 May 2021 11:53:50 +0200
Subject: [PATCH 1/2] Better error message on capitalized type

---
 src/res_core.ml                          | 25 +++++++++++++++++++++---
 tests/parsing/errors/typeDef/typeDef.res |  3 +++
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/src/res_core.ml b/src/res_core.ml
index a03e1af1..2b053cff 100644
--- a/src/res_core.ml
+++ b/src/res_core.ml
@@ -728,8 +728,14 @@ let parseValuePath p =
   | Lident ident -> Longident.Lident ident
   | Uident ident ->
     Parser.next p;
-    Parser.expect Dot p;
-    aux p (Lident ident)
+    begin match p.token with
+      | Dot ->
+        Parser.next p;
+        aux p (Lident ident)
+      | _ ->
+        Parser.err p (Diagnostics.message "Identifier needs to be lower-cased.");
+        Longident.Lident ident
+    end
   | token ->
     Parser.err p (Diagnostics.unexpected token p.breadcrumbs);
     Longident.Lident "_"
@@ -5223,7 +5229,20 @@ and parseTypeDefinitionOrExtension ~attrs p =
       Asttypes.Nonrecursive
     | _ -> Asttypes.Nonrecursive
   in
-  let name = parseValuePath p in
+  (*let name = parseValuePath p in*)
+  let name = match p.token with
+    | Uident ident ->
+      let identStartPos = p.startPos in
+      let identEndPos = p.endPos in
+      Parser.next p;
+      begin match p.token with
+        | Dot -> parseValuePathTail p startPos (Longident.Lident ident)
+        | _ ->
+          Parser.err p ~startPos:identStartPos ~endPos:identEndPos (Diagnostics.message "Type names need to start with a lower-cased letter.");
+          Location.mkloc (Longident.Lident ident) (mkLoc identStartPos identEndPos)
+      end
+    | _ -> parseValuePath p
+  in
   let params = parseTypeParams ~parent:name p in
   match p.Parser.token with
   | PlusEqual ->
diff --git a/tests/parsing/errors/typeDef/typeDef.res b/tests/parsing/errors/typeDef/typeDef.res
index ac77125f..b6091195 100644
--- a/tests/parsing/errors/typeDef/typeDef.res
+++ b/tests/parsing/errors/typeDef/typeDef.res
@@ -9,3 +9,6 @@ type t =
 
 // missing type
 type state =
+
+// name cannot be capitalized
+type User = string

From 204acfb601fa7e029f20f8f61cb2ffc36f4f1a80 Mon Sep 17 00:00:00 2001
From: Iwan <mvalcke@hubspot.com>
Date: Wed, 26 May 2021 13:00:42 +0200
Subject: [PATCH 2/2] Tweak parsing of type definition names to parse the
 correct path

---
 src/res_core.ml                               | 21 +++++++++---------
 .../errors/typeDef/expected/typeDef.res.txt   | 22 +++++++++++++++----
 2 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/src/res_core.ml b/src/res_core.ml
index 2b053cff..262fa3e5 100644
--- a/src/res_core.ml
+++ b/src/res_core.ml
@@ -5229,18 +5229,19 @@ and parseTypeDefinitionOrExtension ~attrs p =
       Asttypes.Nonrecursive
     | _ -> Asttypes.Nonrecursive
   in
-  (*let name = parseValuePath p in*)
   let name = match p.token with
-    | Uident ident ->
-      let identStartPos = p.startPos in
-      let identEndPos = p.endPos in
+  | Uident ident ->
+    let identStartPos = p.startPos in
+    let identEndPos = p.endPos in
+    Parser.next p;
+    begin match p.token with
+    | Dot ->
       Parser.next p;
-      begin match p.token with
-        | Dot -> parseValuePathTail p startPos (Longident.Lident ident)
-        | _ ->
-          Parser.err p ~startPos:identStartPos ~endPos:identEndPos (Diagnostics.message "Type names need to start with a lower-cased letter.");
-          Location.mkloc (Longident.Lident ident) (mkLoc identStartPos identEndPos)
-      end
+      parseValuePathTail p identStartPos (Longident.Lident ident)
+    | _ ->
+      Parser.err p ~startPos:identStartPos ~endPos:identEndPos (Diagnostics.message "Type names need to start with a lower-cased letter.");
+      Location.mkloc (Longident.Lident ident) (mkLoc identStartPos identEndPos)
+    end
     | _ -> parseValuePath p
   in
   let params = parseTypeParams ~parent:name p in
diff --git a/tests/parsing/errors/typeDef/expected/typeDef.res.txt b/tests/parsing/errors/typeDef/expected/typeDef.res.txt
index 8b73f7a8..097b5095 100644
--- a/tests/parsing/errors/typeDef/expected/typeDef.res.txt
+++ b/tests/parsing/errors/typeDef/expected/typeDef.res.txt
@@ -29,21 +29,35 @@
   10 │ // missing type
   11 │ type state =
   12 │ 
+  13 │ // name cannot be capitalized
 
   Missing a type here
 
 
   Syntax error!
-  tests/parsing/errors/typeDef/typeDef.res:12:1
+  tests/parsing/errors/typeDef/typeDef.res:14:1-4
 
-  10 │ // missing type
-  11 │ type state =
   12 │ 
+  13 │ // name cannot be capitalized
+  14 │ type User = string
+  15 │ 
 
   Missing a type here
 
+
+  Syntax error!
+  tests/parsing/errors/typeDef/typeDef.res:14:6-9
+
+  12 │ 
+  13 │ // name cannot be capitalized
+  14 │ type User = string
+  15 │ 
+
+  Type names need to start with a lower-cased letter.
+
 type stack =
   | Empty 
 type nonrec bar = string
 type nonrec t = [%rescript.typehole ]
-type nonrec state = [%rescript.typehole ]
\ No newline at end of file
+type nonrec state = [%rescript.typehole ]
+type nonrec User = string
\ No newline at end of file