JS: Fix handling of typeof

Author: asgerf

javascript/ql/lib/semmle/javascript/internal/TypeResolution.qll

@@ -126,6 +126,11 @@ module TypeResolution {
       node1 = fun.getFunction() and
       node2 = fun
     )
+    or
+    exists(TypeofTypeExpr type |
+      node1 = type.getExpressionName() and
+      node2 = type
+    )
   }
 
   /**
@@ -144,6 +149,12 @@ module TypeResolution {
       node2 = access
     )
     or
+    exists(QualifiedVarTypeAccess access |
+      node1 = access.getQualifier() and
+      name = access.getIdentifier().getName() and
+      node2 = access
+    )
+    or
     exists(PropAccess access |
       node1 = access.getBase() and
       name = access.getPropertyName() and

javascript/ql/lib/semmle/javascript/internal/UnderlyingTypes.qll

@@ -62,7 +62,11 @@ module UnderlyingTypes {
     exists(Node mid |
       nodeRefersToModule(mid, mod, qualifiedName) and
       ValueFlow::step(mid, node) and
-      not node instanceof Variable // avoid a lot of unnecessary tuples
+      // avoid a lot of unnecessary tuples
+      not (
+        node instanceof Variable and
+        not node = any(LocalVarTypeAccess ac).getVariable() // needed for TypeofTypeExpr
+      )
     )
     or
     exists(Node mid, string prefix, string step |
@@ -145,11 +149,7 @@ module UnderlyingTypes {
   }
 
   predicate nodeHasUnderlyingType(Node node, string mod, string name) {
-    exists(Node mid, string prefix, string step |
-      nodeRefersToModule(mid, mod, prefix) and
-      readStep(mid, step, node) and
-      name = append(prefix, step)
-    )
+    nodeRefersToModule(node, mod, name)
     or
     exists(JSDocNamedTypeExpr type |
       node = type and

javascript/ql/test/library-tests/UnderlyingTypes/expressWrapperExport.use.ts

@@ -24,3 +24,6 @@ function t7(req: w.Request) { // none
 
 function t8(res: w.Response) { // none
 }
+
+function t9(e: typeof w.wrapper) { // $ hasUnderlyingType='express'
+}

javascript/ql/test/library-tests/UnderlyingTypes/namespaceImport.ts

@@ -1,6 +1,6 @@
 import * as express from 'express';
 
-function t1(e: typeof express) { // $ MISSING: hasUnderlyingType='express'
+function t1(e: typeof express) { // $ hasUnderlyingType='express'
 }
 
 function t2(req: express.Request) { // $ hasUnderlyingType='express'.Request