From 64f58b74f6a4ac346e1199f7eca221d910d6b327 Mon Sep 17 00:00:00 2001
From: Asger Feldthaus <asgerf@github.com>
Date: Fri, 7 Aug 2020 11:55:26 +0100
Subject: [PATCH] JS: Fix extractor crash when some parameters have no type
 annotation

---
 .../extractor/src/com/semmle/js/extractor/ScopeManager.java   | 4 +++-
 .../RegressionTests/PartialFunctionArgs/Test.expected         | 1 +
 .../TypeScript/RegressionTests/PartialFunctionArgs/Test.ql    | 4 ++++
 .../RegressionTests/PartialFunctionArgs/tsconfig.json         | 3 +++
 .../TypeScript/RegressionTests/PartialFunctionArgs/tst.ts     | 1 +
 5 files changed, 12 insertions(+), 1 deletion(-)
 create mode 100644 javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/Test.expected
 create mode 100644 javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/Test.ql
 create mode 100644 javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/tsconfig.json
 create mode 100644 javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/tst.ts

diff --git a/javascript/extractor/src/com/semmle/js/extractor/ScopeManager.java b/javascript/extractor/src/com/semmle/js/extractor/ScopeManager.java
index 3bffa4ad3ae4..109b73f23097 100644
--- a/javascript/extractor/src/com/semmle/js/extractor/ScopeManager.java
+++ b/javascript/extractor/src/com/semmle/js/extractor/ScopeManager.java
@@ -622,7 +622,9 @@ public Void visit(FunctionExpression nd, Void c) {
               nd.getReturnType().accept(this, c);
             }
             for (ITypeExpression paramType : nd.getParameterTypes()) {
-              paramType.accept(this, c);
+              if (paramType != null) {
+                paramType.accept(this, c);
+              }
             }
             // note: `infer` types may not occur in type parameter bounds.
             return null;
diff --git a/javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/Test.expected b/javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/Test.expected
new file mode 100644
index 000000000000..20f2f4b6afa8
--- /dev/null
+++ b/javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/Test.expected
@@ -0,0 +1 @@
+| tst.ts:1:1:1:61 | type Fo ... : never | tst.ts:1:15:1:61 | T exten ... : never |
diff --git a/javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/Test.ql b/javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/Test.ql
new file mode 100644
index 000000000000..e6934ec24889
--- /dev/null
+++ b/javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/Test.ql
@@ -0,0 +1,4 @@
+import javascript
+
+from TypeAliasDeclaration decl
+select decl, decl.getDefinition()
diff --git a/javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/tsconfig.json b/javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/tsconfig.json
new file mode 100644
index 000000000000..a1aaa6366d3b
--- /dev/null
+++ b/javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/tsconfig.json
@@ -0,0 +1,3 @@
+{
+    "include": ["."]
+}
\ No newline at end of file
diff --git a/javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/tst.ts b/javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/tst.ts
new file mode 100644
index 000000000000..4fc0417a6301
--- /dev/null
+++ b/javascript/ql/test/library-tests/TypeScript/RegressionTests/PartialFunctionArgs/tst.ts
@@ -0,0 +1 @@
+type Foo<T> = T extends (a, ...b: infer U) => any ? U : never