From 47e027b50b68e56611400089d4b016c84d32e1e0 Mon Sep 17 00:00:00 2001
From: dcode <dcode@dcode.io>
Date: Fri, 6 Jan 2023 19:21:39 +0100
Subject: [PATCH 1/3] Support trailing comma in function types

---
 src/parser.ts                            | 4 ++++
 tests/parser/function-type.ts            | 1 +
 tests/parser/function-type.ts.fixture.ts | 1 +
 3 files changed, 6 insertions(+)

diff --git a/src/parser.ts b/src/parser.ts
index 166c3d4132..8eaffed790 100644
--- a/src/parser.ts
+++ b/src/parser.ts
@@ -795,6 +795,10 @@ export class Parser extends DiagnosticEmitter {
               firstParamKind = kind;
             }
           }
+        } else if (parameters && parameters.length && tn.peek() == Token.CloseParen) { // allow trailing comma
+          isSignature = true;
+          tn.discard(state);
+          break;
         } else {
           if (isSignature) {
             this.error(
diff --git a/tests/parser/function-type.ts b/tests/parser/function-type.ts
index 4c9a385fe5..f547cdeefa 100644
--- a/tests/parser/function-type.ts
+++ b/tests/parser/function-type.ts
@@ -3,3 +3,4 @@ var b: (a: i32, b: i32) => void;
 var c: (a: i32, b: i32) => (a: i32, b: i32) => void;
 var d: (a: i32, a: i32) => void; // NOTE: duplicates in type signatures doesn't in TypeScript
 var e: (a) => void; // TS1110
+var f: (a: i32, b: i32,) => (a: i32, b: i32,) => void;
diff --git a/tests/parser/function-type.ts.fixture.ts b/tests/parser/function-type.ts.fixture.ts
index 061e00711d..e4e6aa7888 100644
--- a/tests/parser/function-type.ts.fixture.ts
+++ b/tests/parser/function-type.ts.fixture.ts
@@ -3,4 +3,5 @@ var b: (a: i32, b: i32) => void;
 var c: (a: i32, b: i32) => (a: i32, b: i32) => void;
 var d: (a: i32, a: i32) => void;
 var e: (a) => void;
+var f: (a: i32, b: i32) => (a: i32, b: i32) => void;
 // ERROR 1110: "Type expected." in function-type.ts(5,10+0)

From b36fc3a459307f95287fa8af812b830f22fcf70d Mon Sep 17 00:00:00 2001
From: dcode <dcode@dcode.io>
Date: Fri, 6 Jan 2023 23:35:45 +0100
Subject: [PATCH 2/3] simplify

---
 src/parser.ts | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/parser.ts b/src/parser.ts
index 8eaffed790..e027349f6c 100644
--- a/src/parser.ts
+++ b/src/parser.ts
@@ -795,9 +795,8 @@ export class Parser extends DiagnosticEmitter {
               firstParamKind = kind;
             }
           }
-        } else if (parameters && parameters.length && tn.peek() == Token.CloseParen) { // allow trailing comma
-          isSignature = true;
-          tn.discard(state);
+        } else if (parameters && tn.peek() == Token.CloseParen) { // allow trailing comma
+          assert(isSignature && parameters.length);
           break;
         } else {
           if (isSignature) {

From bc1bd25385120c91fc58014f7687a788483a8f0a Mon Sep 17 00:00:00 2001
From: dcode <dcode@dcode.io>
Date: Fri, 6 Jan 2023 23:37:16 +0100
Subject: [PATCH 3/3] simplify

---
 src/parser.ts | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/parser.ts b/src/parser.ts
index e027349f6c..cade050161 100644
--- a/src/parser.ts
+++ b/src/parser.ts
@@ -795,11 +795,9 @@ export class Parser extends DiagnosticEmitter {
               firstParamKind = kind;
             }
           }
-        } else if (parameters && tn.peek() == Token.CloseParen) { // allow trailing comma
-          assert(isSignature && parameters.length);
-          break;
         } else {
           if (isSignature) {
+            if (tn.peek() == Token.CloseParen) break; // allow trailing comma
             this.error(
               DiagnosticCode.Identifier_expected,
               tn.range()