JS: Declare variables from ambient declarations

fixup

Author: asgerf

javascript/extractor/src/com/semmle/js/extractor/HTMLExtractor.java

@@ -40,7 +40,8 @@ public JavaScriptHTMLElementHandler(TextualExtractor textualExtractor) {
       this.textualExtractor = textualExtractor;
 
       this.scopeManager =
-          new ScopeManager(textualExtractor.getTrapwriter(), config.getEcmaVersion(), true);
+          new ScopeManager(textualExtractor.getTrapwriter(), config.getEcmaVersion(),
+            ScopeManager.FileKind.TEMPLATE);
     }
 
     /*
@@ -425,7 +426,7 @@ private void extractTemplateTags(
           extractSnippet(
               TopLevelKind.ANGULAR_STYLE_TEMPLATE,
               config.withSourceType(SourceType.ANGULAR_STYLE_TEMPLATE),
-              new ScopeManager(textualExtractor.getTrapwriter(), ECMAVersion.ECMA2020, true),
+              new ScopeManager(textualExtractor.getTrapwriter(), ECMAVersion.ECMA2020, ScopeManager.FileKind.TEMPLATE),
               textualExtractor,
               m.group(bodyGroup),
               m.start(bodyGroup),

javascript/extractor/src/com/semmle/js/extractor/ScopeManager.java

@@ -97,28 +97,43 @@ public Label lookupNamespace(String name) {
     }
   }
 
+  public static enum FileKind {
+    /** Any file not specific to one of the other file kinds. */
+    PLAIN,
+
+    /** A file potentially containing template tags. */
+    TEMPLATE,
+
+    /** A d.ts file, containing TypeScript ambient declarations. */
+    TYPESCRIPT_DECLARATION,
+  }
+
   private final TrapWriter trapWriter;
   private Scope curScope;
   private final Scope toplevelScope;
   private final ECMAVersion ecmaVersion;
   private final Set<String> implicitGlobals = new LinkedHashSet<String>();
   private Scope implicitVariableScope;
-  private final boolean isInTemplateScope;
+  private final FileKind fileKind;
 
-  public ScopeManager(TrapWriter trapWriter, ECMAVersion ecmaVersion, boolean isInTemplateScope) {
+  public ScopeManager(TrapWriter trapWriter, ECMAVersion ecmaVersion, FileKind fileKind) {
     this.trapWriter = trapWriter;
     this.toplevelScope = enterScope(ScopeKind.GLOBAL, trapWriter.globalID("global_scope"), null);
     this.ecmaVersion = ecmaVersion;
-    this.implicitVariableScope = toplevelScope; 
-    this.isInTemplateScope = isInTemplateScope;
+    this.implicitVariableScope = toplevelScope;
+    this.fileKind = fileKind;
   }
 
   /**
    * Returns true the current scope is potentially in a template file, and may contain
    * relevant template tags.
    */
   public boolean isInTemplateFile() {
-    return isInTemplateScope;
+    return this.fileKind == FileKind.TEMPLATE;
+  }
+
+  public boolean isInTypeScriptDeclarationFile() {
+    return this.fileKind == FileKind.TYPESCRIPT_DECLARATION;
   }
 
   /**
@@ -221,7 +236,7 @@ public Scope getToplevelScope() {
 
   /**
    * Get the label for a given variable in the current scope; if it cannot be found, add it to the
-   * implicit variable scope (usually the global scope). 
+   * implicit variable scope (usually the global scope).
    */
   public Label getVarKey(String name) {
     Label lbl = curScope.lookupVariable(name);
@@ -411,15 +426,15 @@ public Void visit(Identifier nd, Void v) {
       // cases where we turn on the 'declKind' flags
       @Override
       public Void visit(FunctionDeclaration nd, Void v) {
-        if (nd.hasDeclareKeyword()) return null;
+        if (nd.hasDeclareKeyword() && !isInTypeScriptDeclarationFile()) return null;
         // strict mode functions are block-scoped, non-strict mode ones aren't
         if (blockscope == isStrict) visit(nd.getId(), DeclKind.var);
         return null;
       }
 
       @Override
       public Void visit(ClassDeclaration nd, Void c) {
-        if (nd.hasDeclareKeyword()) return null;
+        if (nd.hasDeclareKeyword() && !isInTypeScriptDeclarationFile()) return null;
         if (blockscope) visit(nd.getClassDef().getId(), DeclKind.varAndType);
         return null;
       }
@@ -468,7 +483,7 @@ public Void visit(EnhancedForStatement nd, Void v) {
 
       @Override
       public Void visit(VariableDeclaration nd, Void v) {
-        if (nd.hasDeclareKeyword()) return null;
+        if (nd.hasDeclareKeyword() && !isInTypeScriptDeclarationFile()) return null;
         // in block scoping mode, only process 'let'; in non-block scoping
         // mode, only process non-'let'
         if (blockscope == nd.isBlockScoped(ecmaVersion)) visit(nd.getDeclarations());
@@ -503,7 +518,8 @@ public Void visit(ClassBody nd, Void c) {
       @Override
       public Void visit(NamespaceDeclaration nd, Void c) {
         if (blockscope) return null;
-        boolean hasVariable = nd.isInstantiated() && !nd.hasDeclareKeyword();
+        boolean isAmbientOutsideDtsFile = nd.hasDeclareKeyword() && !isInTypeScriptDeclarationFile();
+        boolean hasVariable = nd.isInstantiated() && !isAmbientOutsideDtsFile;
         visit(nd.getName(), hasVariable ? DeclKind.varAndNamespace : DeclKind.namespace);
         return null;
       }

javascript/extractor/src/com/semmle/js/extractor/ScriptExtractor.java

@@ -77,7 +77,7 @@ public LoCInfo extract(TextualExtractor textualExtractor) {
     }
 
     ScopeManager scopeManager =
-        new ScopeManager(textualExtractor.getTrapwriter(), config.getEcmaVersion(), false);
+        new ScopeManager(textualExtractor.getTrapwriter(), config.getEcmaVersion(), ScopeManager.FileKind.PLAIN);
     Label toplevelLabel = null;
     LoCInfo loc;
     try {

javascript/extractor/src/com/semmle/js/extractor/TypeScriptExtractor.java

@@ -22,8 +22,10 @@ public LoCInfo extract(TextualExtractor textualExtractor) {
     String source = textualExtractor.getSource();
     File sourceFile = textualExtractor.getExtractedFile();
     Result res = state.getTypeScriptParser().parse(sourceFile, source, textualExtractor.getMetrics());
-    ScopeManager scopeManager =
-        new ScopeManager(textualExtractor.getTrapwriter(), ECMAVersion.ECMA2017, false);
+    ScopeManager.FileKind fileKind = sourceFile.getName().endsWith(".d.ts")
+        ? ScopeManager.FileKind.TYPESCRIPT_DECLARATION
+        : ScopeManager.FileKind.PLAIN;
+    ScopeManager scopeManager = new ScopeManager(textualExtractor.getTrapwriter(), ECMAVersion.ECMA2017, fileKind);
     try {
       FileSnippet snippet = state.getSnippets().get(sourceFile.toPath());
       SourceType sourceType = snippet != null ? snippet.getSourceType() : jsExtractor.establishSourceType(source, false);