JS: Handle name resolution through dynamic imports

Author: asgerf

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

@@ -46,6 +46,9 @@ module NameResolution {
       this instanceof Module
       or
       this instanceof NamespaceDefinition // `module {}` or `enum {}` statement
+      or
+      // A module wrapped in a promise. We model this as a module exporting the actual module in a property called `$$promise-content`.
+      this instanceof DynamicImportExpr
     }
   }
 
@@ -232,6 +235,19 @@ module NameResolution {
       name = expr.getName() and
       node2 = expr
     )
+    or
+    exists(AwaitExpr await |
+      node1 = await.getOperand() and
+      name = "$$promise-content" and
+      node2 = await
+    )
+    or
+    exists(MethodCallExpr call |
+      call.getMethodName() = "then" and
+      node1 = call.getReceiver() and
+      name = "$$promise-content" and
+      node2 = call.getArgument(0).(Function).getParameter(0)
+    )
   }
 
   private signature module TypeResolutionInputSig {
@@ -334,6 +350,12 @@ module NameResolution {
       )
       or
       storeToVariable(result, name, mod.(Closure::ClosureModule).getExportsVariable())
+      or
+      exists(DynamicImportExpr imprt |
+        mod = imprt and
+        name = "$$promise-content" and
+        result = imprt.getImportedPathExpr()
+      )
     }
 
     /**

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

@@ -1,4 +1,4 @@
 async function t1() {
     const e = await import('./dynamicImportLib');
-    e.getRequest(); // $ MISSING: hasUnderlyingType='express'.Request
+    e.getRequest(); // $ hasUnderlyingType='express'.Request
 }

javascript/ql/test/library-tests/UnderlyingTypes/test.expected

@@ -15,6 +15,7 @@
 | contextualTypes.ts:27:16:27:18 | req | 'express'.Request |
 | contextualTypes.ts:34:20:34:22 | req | 'express'.Request |
 | contextualTypes.ts:41:16:41:18 | req | 'express'.Request |
+| dynamicImportUse.ts:3:5:3:18 | e.getRequest() | 'express'.Request |
 | expressBulkExport.use.ts:3:13:3:15 | req | 'express'.Request |
 | expressBulkExport.use.ts:6:13:6:15 | res | 'express'.Response |
 | expressExportAssign.use.ts:3:13:3:15 | req | 'express'.Request |