JS: Update getTypeAnnotation() to return TypeAnnotations

javascript/ql/src/semmle/javascript/Classes.qll

@@ -551,7 +551,11 @@ class SetterMethodSignature extends SetterMethodDeclaration, AccessorMethodSigna
  */
 class FieldDeclaration extends MemberDeclaration, @field {
   /** Gets the type annotation of this field, if any, such as `T` in `{ x: T }`. */
-  TypeExpr getTypeAnnotation() { result = getChildTypeExpr(2) }
+  TypeAnnotation getTypeAnnotation() {
+    result = getChildTypeExpr(2)
+    or
+    result = getDocumentation().getATagByTitle("type").getType()
+  }
 
   /** Holds if this is a TypeScript field annotated with the `readonly` keyword. */
   predicate isReadonly() { hasReadonlyKeyword(this) }
@@ -591,7 +595,7 @@ class ParameterField extends FieldDeclaration, @parameter_field {
 
   override Expr getNameExpr() { result = getParameter() }
 
-  override TypeExpr getTypeAnnotation() { result = getParameter().getTypeAnnotation() }
+  override TypeAnnotation getTypeAnnotation() { result = getParameter().getTypeAnnotation() }
 }
 
 /**

javascript/ql/src/semmle/javascript/Functions.qll

@@ -38,7 +38,11 @@ class Function extends @function, Parameterized, TypeParameterized, StmtContaine
    *
    * `this` parameter types are specific to TypeScript.
    */
-  TypeExpr getThisTypeAnnotation() { result = getChildTypeExpr(-4) }
+  TypeAnnotation getThisTypeAnnotation() {
+    result = getChildTypeExpr(-4)
+    or
+    result = getDocumentation().getATagByTitle("this").getType()
+  }
 
   /** Gets the identifier specifying the name of this function, if any. */
   VarDecl getId() { result = getChildExpr(-1) }
@@ -76,7 +80,13 @@ class Function extends @function, Parameterized, TypeParameterized, StmtContaine
   int getNumBodyStmt() { result = count(getABodyStmt()) }
 
   /** Gets the return type annotation on this function, if any. */
-  TypeExpr getReturnTypeAnnotation() { typeexprs(result, _, this, -3, _) }
+  TypeAnnotation getReturnTypeAnnotation() {
+    typeexprs(result, _, this, -3, _)
+    or
+    exists(string title | title = "return" or title = "returns" |
+      result = getDocumentation().getATagByTitle(title).getType()
+    )
+  }
 
   /** Holds if this function is a generator function. */
   predicate isGenerator() {

javascript/ql/src/semmle/javascript/JSDoc.qll

@@ -17,6 +17,12 @@ class JSDoc extends @jsdoc, Locatable {
   /** Gets a JSDoc tag within this JSDoc comment. */
   JSDocTag getATag() { result.getParent() = this }
 
+  /** Gets a JSDoc tag within this JSDoc comment with the given title. */
+  JSDocTag getATagByTitle(string title) {
+    result = getATag() and
+    result.getTitle() = title
+  }
+
   override string toString() { result = getComment().toString() }
 }
 

javascript/ql/src/semmle/javascript/Variables.qll

@@ -326,7 +326,7 @@ class BindingPattern extends @pattern, Expr {
   predicate isLValue() { any() }
 
   /**
-   * Returns the TypeScript type annotation for this variable or pattern, if any.
+   * Returns the type annotation for this variable or pattern, if any.
    *
    * Only the outermost part of a binding pattern can have a type annotation.
    * For instance, in the declaration,
@@ -336,7 +336,7 @@ class BindingPattern extends @pattern, Expr {
    * the variable `x` has no type annotation, whereas the pattern `{x}` has the type
    * annotation `Point`.
    */
-  TypeExpr getTypeAnnotation() {
+  TypeAnnotation getTypeAnnotation() {
     exists(VariableDeclarator decl | decl.getBindingPattern() = this |
       result = decl.getTypeAnnotation()
     )
@@ -501,7 +501,11 @@ class VariableDeclarator extends Expr, @vardeclarator {
   Expr getInit() { result = this.getChildExpr(1) }
 
   /** Gets the TypeScript type annotation for the declared variable or binding pattern. */
-  TypeExpr getTypeAnnotation() { result = this.getChildTypeExpr(2) }
+  TypeAnnotation getTypeAnnotation() {
+    result = this.getChildTypeExpr(2)
+    or
+    result = getDeclStmt().getDocumentation().getATagByTitle("type").getType()
+  }
 
   /** Holds if this is a TypeScript variable marked as definitely assigned with the `!` operator. */
   predicate hasDefiniteAssignmentAssertion() { hasDefiniteAssignmentAssertion(this) }
@@ -569,8 +573,10 @@ class Parameter extends BindingPattern {
   }
 
   /** Gets the type annotation for this parameter, if any. */
-  override TypeExpr getTypeAnnotation() {
+  override TypeAnnotation getTypeAnnotation() {
     exists(Function f, int n | this = f.getParameter(n) | result = f.getChildTypeExpr(-(4 * n + 6)))
+    or
+    result = getJSDocTag().getType()
   }
 
   /** Holds if this parameter is a rest parameter. */