JS: Name and type resolution and underlying types

Author: asgerf

Diff for: javascript/ql/lib/semmle/javascript/TypeScript.qll

@@ -1,4 +1,5 @@
 import javascript
+private import semmle.javascript.internal.UnderlyingTypes
 
 /**
  * A statement that defines a namespace, that is, a namespace declaration or enum declaration.
@@ -577,7 +578,7 @@ class TypeExpr extends ExprOrType, @typeexpr, TypeAnnotation {
   override TopLevel getTopLevel() { result = ExprOrType.super.getTopLevel() }
 
   override DataFlow::ClassNode getClass() {
-    result.getAstNode() = this.getType().(ClassType).getClass()
+    UnderlyingTypes::nodeHasUnderlyingClassType(this, result.getAstNode())
   }
 }
 

Diff for: javascript/ql/lib/semmle/javascript/Variables.qll

@@ -27,6 +27,12 @@ class Scope extends @scope {
     result = this.getAVariable() and
     result.getName() = name
   }
+
+  /** Gets the local type name with the given name declared in this scope. */
+  LocalTypeName getLocalTypeName(string name) {
+    result.getScope() = this and
+    result.getName() = name
+  }
 }
 
 /**

Diff for: javascript/ql/lib/semmle/javascript/dataflow/DataFlow.qll

@@ -27,6 +27,9 @@ private import internal.PreCallGraphStep
 private import semmle.javascript.internal.CachedStages
 private import semmle.javascript.dataflow.internal.DataFlowPrivate as Private
 private import semmle.javascript.dataflow.internal.VariableOrThis
+private import semmle.javascript.internal.NameResolution
+private import semmle.javascript.internal.UnderlyingTypes
+private import semmle.javascript.internal.TypeResolution
 
 module DataFlow {
   /**
@@ -189,26 +192,6 @@ module DataFlow {
       FlowSteps::identityFunctionStep(result, this)
     }
 
-    /**
-     * Gets the static type of this node as determined by the TypeScript type system.
-     */
-    private Type getType() {
-      exists(AST::ValueNode node |
-        this = TValueNode(node) and
-        ast_node_type(node, result)
-      )
-      or
-      exists(BindingPattern pattern |
-        this = lvalueNode(pattern) and
-        ast_node_type(pattern, result)
-      )
-      or
-      exists(MethodDefinition def |
-        this = TThisNode(def.getInit()) and
-        ast_node_type(def.getDeclaringClass(), result)
-      )
-    }
-
     /**
      * Gets the type annotation describing the type of this node,
      * provided that a static type could not be found.
@@ -229,16 +212,26 @@ module DataFlow {
       )
     }
 
+    private NameResolution::Node getNameResolutionNode() {
+      this = valueNode(result)
+      or
+      exists(PropertyPattern pattern |
+        result = pattern.getValuePattern() and
+        this = TPropNode(pattern)
+      )
+    }
+
     /**
      * Holds if this node is annotated with the given named type,
      * or is declared as a subtype thereof, or is a union or intersection containing such a type.
      */
     cached
     predicate hasUnderlyingType(string globalName) {
       Stages::TypeTracking::ref() and
-      this.getType().hasUnderlyingType(globalName)
-      or
-      this.getFallbackTypeAnnotation().getAnUnderlyingType().hasQualifiedName(globalName)
+      exists(NameResolution::Node type |
+        TypeResolution::valueHasType(this.getNameResolutionNode(), type) and
+        UnderlyingTypes::nodeHasUnderlyingType(type, "global", globalName)
+      )
     }
 
     /**
@@ -248,9 +241,11 @@ module DataFlow {
     cached
     predicate hasUnderlyingType(string moduleName, string typeName) {
       Stages::TypeTracking::ref() and
-      this.getType().hasUnderlyingType(moduleName, typeName)
-      or
-      this.getFallbackTypeAnnotation().getAnUnderlyingType().hasQualifiedName(moduleName, typeName)
+      moduleName != "global" and
+      exists(NameResolution::Node type |
+        TypeResolution::valueHasType(this.getNameResolutionNode(), type) and
+        UnderlyingTypes::nodeHasUnderlyingType(type, moduleName, typeName)
+      )
     }
 
     /**