From 148a494c90d0849ad94de02f34975dd8960e22be Mon Sep 17 00:00:00 2001
From: Tingan Ho <tingan87@gmail.com>
Date: Sun, 30 Jul 2017 10:31:31 +0200
Subject: [PATCH] Adds transformers for ignored catch parameter

---
 src/compiler/transformers/es2015.ts | 2 +-
 src/compiler/transformers/esnext.ts | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts
index f97de018d4a..ebfd0b0069f 100644
--- a/src/compiler/transformers/es2015.ts
+++ b/src/compiler/transformers/es2015.ts
@@ -3173,7 +3173,7 @@ namespace ts {
         function visitCatchClause(node: CatchClause): CatchClause {
             const ancestorFacts = enterSubtree(HierarchyFacts.BlockScopeExcludes, HierarchyFacts.BlockScopeIncludes);
             let updated: CatchClause;
-            if (isBindingPattern(node.variableDeclaration.name)) {
+            if (node.variableDeclaration && isBindingPattern(node.variableDeclaration.name)) {
                 const temp = createTempVariable(/*recordTempVariable*/ undefined);
                 const newVariableDeclaration = createVariableDeclaration(temp);
                 setTextRange(newVariableDeclaration, node.variableDeclaration);
diff --git a/src/compiler/transformers/esnext.ts b/src/compiler/transformers/esnext.ts
index 3d884001932..597b9d55b16 100644
--- a/src/compiler/transformers/esnext.ts
+++ b/src/compiler/transformers/esnext.ts
@@ -101,6 +101,8 @@ namespace ts {
                     return visitExpressionStatement(node as ExpressionStatement);
                 case SyntaxKind.ParenthesizedExpression:
                     return visitParenthesizedExpression(node as ParenthesizedExpression, noDestructuringValue);
+                case SyntaxKind.CatchClause:
+                    return visitCatchClause(node as CatchClause);
                 default:
                     return visitEachChild(node, visitor, context);
             }
@@ -212,6 +214,13 @@ namespace ts {
             return visitEachChild(node, noDestructuringValue ? visitorNoDestructuringValue : visitor, context);
         }
 
+        function visitCatchClause(node: CatchClause): CatchClause {
+            if (!node.variableDeclaration) {
+                return updateCatchClause(node, createVariableDeclaration("_ignoredCatchParameter"), node.block);
+            }
+            return visitEachChild(node, visitor, context);
+        }
+
         /**
          * Visits a BinaryExpression that contains a destructuring assignment.
          *