JS: Fix support for selective re-export

Author: asgerf

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

@@ -167,6 +167,13 @@ module TypeResolution {
       node2 = spec.getLocal()
     )
     or
+    exists(SelectiveReExportDeclaration exprt, ExportSpecifier spec |
+      spec = exprt.getASpecifier() and
+      node1 = exprt.getImportedPath() and
+      name = spec.getLocalName() and
+      node2 = spec.getLocal()
+    )
+    or
     // Support JSDoc expressions of the form 'foo.bar' where 'foo' is an import
     // at the top-level.
     exists(JSDocNamedTypeExpr expr, string prefix |
@@ -234,6 +241,16 @@ module TypeResolution {
         name = spec.getExportedName()
       )
       or
+      exists(SelectiveReExportDeclaration exprt, ExportSpecifier spec |
+        // `export { A as B } from 'blah'`
+        // This is not covered by `exportsAs` above because neither A or B is a LexicalName
+        // (both are property names) so it doesn't fit the interface of `exportsAs`.
+        spec = exprt.getASpecifier() and
+        mod = exprt.getContainer() and
+        name = spec.getExportedName() and
+        result = spec.getLocal()
+      )
+      or
       exists(EnumDeclaration enum |
         mod = enum and
         result = enum.getMemberByName(name).getIdentifier()

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

@@ -1,10 +1,10 @@
 import { Request, Response, R } from './expressSelectiveExport';
 
-function t1(req: Request) { // $ MISSING: hasUnderlyingType='express'.Request
+function t1(req: Request) { // $ hasUnderlyingType='express'.Request
 }
 
 function t2(res: Response) { // none, not exported
 }
 
-function t3(res: R) { // $ MISSING: hasUnderlyingType='express'.Response
+function t3(res: R) { // $ hasUnderlyingType='express'.Response
 }