From a870b068342165f299d619833f0fc159e186ed5e Mon Sep 17 00:00:00 2001
From: Jason Freeman <jfreeman@microsoft.com>
Date: Mon, 13 Oct 2014 18:25:51 -0700
Subject: [PATCH 1/2] Fix signature help crash when requested outside argument
 list

---
 src/services/formatting/smartIndenter.ts         |  2 +-
 src/services/signatureHelp.ts                    |  8 ++------
 src/services/utilities.ts                        | 16 +++++++++-------
 .../fourslash/noSignatureHelpOnNewKeyword.ts     | 14 ++++++++++++++
 4 files changed, 26 insertions(+), 14 deletions(-)
 create mode 100644 tests/cases/fourslash/noSignatureHelpOnNewKeyword.ts

diff --git a/src/services/formatting/smartIndenter.ts b/src/services/formatting/smartIndenter.ts
index 79b238c893d..12d36dd4d2b 100644
--- a/src/services/formatting/smartIndenter.ts
+++ b/src/services/formatting/smartIndenter.ts
@@ -108,7 +108,7 @@ module ts.formatting {
         function getActualIndentationForListItemBeforeComma(commaToken: Node, sourceFile: SourceFile, options: TypeScript.FormattingOptions): number {
             // previous token is comma that separates items in list - find the previous item and try to derive indentation from it
             var commaItemInfo = findListItemInfo(commaToken);
-            Debug.assert(commaItemInfo.listItemIndex > 0);
+            Debug.assert(commaItemInfo && commaItemInfo.listItemIndex > 0);
             // The item we're interested in is right before the comma
             return deriveActualIndentationFromList(commaItemInfo.list.getChildren(), commaItemInfo.listItemIndex - 1, sourceFile, options);
         }
diff --git a/src/services/signatureHelp.ts b/src/services/signatureHelp.ts
index 273cfda99b8..d9d221ee65d 100644
--- a/src/services/signatureHelp.ts
+++ b/src/services/signatureHelp.ts
@@ -226,12 +226,8 @@ module ts.SignatureHelp {
                 };
             }
 
-            if (node.kind === SyntaxKind.GreaterThanToken
-                || node.kind === SyntaxKind.CloseParenToken
-                || node === parent.func) {
-                return undefined;
-            }
-
+            // findListItemInfo can return undefined if we are not in parent's argument list
+            // or type argument list.
             return findListItemInfo(node);
         }
 
diff --git a/src/services/utilities.ts b/src/services/utilities.ts
index 4ceb20fdcee..5b77a2b84a5 100644
--- a/src/services/utilities.ts
+++ b/src/services/utilities.ts
@@ -7,6 +7,15 @@ module ts {
 
     export function findListItemInfo(node: Node): ListItemInfo {
         var syntaxList = findContainingList(node);
+
+        // It is possible at this point for syntaxList to be undefined, either if
+        // node.parent had no list child, or if none of its list children contained
+        // the span of node. If this happens, return undefined. The caller should
+        // handle this case.
+        if (!syntaxList) {
+            return undefined;
+        }
+
         var children = syntaxList.getChildren();
         var index = indexOf(children, node);
 
@@ -32,13 +41,6 @@ module ts {
             }
         });
 
-        // syntaxList should not be undefined here. If it is, there is a problem. Find out if
-        // there at least is a child that is a list.
-        if (!syntaxList) {
-            Debug.assert(findChildOfKind(node.parent, SyntaxKind.SyntaxList),
-                "Node of kind " + SyntaxKind[node.parent.kind] + " has no list children");
-        }
-
         return syntaxList;
     }
 
diff --git a/tests/cases/fourslash/noSignatureHelpOnNewKeyword.ts b/tests/cases/fourslash/noSignatureHelpOnNewKeyword.ts
new file mode 100644
index 00000000000..30314b1c665
--- /dev/null
+++ b/tests/cases/fourslash/noSignatureHelpOnNewKeyword.ts
@@ -0,0 +1,14 @@
+///<reference path="fourslash.ts"/>
+
+////class Foo { }
+////new/*1*/ Foo
+////new /*2*/Foo(/*3*/)
+
+goTo.marker('1');
+verify.not.signatureHelpPresent();
+
+goTo.marker('2');
+verify.not.signatureHelpPresent();
+
+goTo.marker('3');
+verify.signatureHelpPresent();
\ No newline at end of file

From 8b4bbb9311cb193ed1e310668c78da47d103078b Mon Sep 17 00:00:00 2001
From: Jason Freeman <jfreeman@microsoft.com>
Date: Tue, 14 Oct 2014 11:23:36 -0700
Subject: [PATCH 2/2] Comment examples of when findListItemInfo can return
 undefined

---
 src/services/signatureHelp.ts | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/services/signatureHelp.ts b/src/services/signatureHelp.ts
index d9d221ee65d..e9375818c11 100644
--- a/src/services/signatureHelp.ts
+++ b/src/services/signatureHelp.ts
@@ -227,7 +227,11 @@ module ts.SignatureHelp {
             }
 
             // findListItemInfo can return undefined if we are not in parent's argument list
-            // or type argument list.
+            // or type argument list. This includes cases where the cursor is:
+            //   - To the right of the closing paren
+            //   - Between the type arguments and the arguments (greater than token)
+            //   - On the target of the call (parent.func)
+            //   - On the 'new' keyword in a 'new' expression
             return findListItemInfo(node);
         }