changes to documentation and small change in returnsVoid based on code-review

javascript/ql/src/Statements/UseOfReturnlessFunction.qhelp

@@ -4,7 +4,7 @@
 <qhelp>
 <overview>
 <p>
-JavaScript functions that do not return any value will implicitly return 
+JavaScript functions that do not return an expression will implicitly return 
 <code>undefined</code>. Using the implicit return value from such a function  
 is not an error in itself, but it is a pattern indicating that some
 misunderstanding has occurred. 
@@ -14,8 +14,7 @@ misunderstanding has occurred.
 <recommendation>
 
 <p>
-Do not use the return value from a function that does not explicitly return 
-a value.
+Do not use the return value from a function that does not return an expression.
 </p>
 
 </recommendation>
@@ -23,10 +22,10 @@ a value.
 
 <p>
 In the example below, the function <code>renderText</code> is used to render 
-text through side effects, and the function does not return a value. 
+text through side effects, and the function does not return an expression. 
 However, the programmer still uses the return value from 
-<code>renderText</code> as if the function returned a value, which is clearly 
-an error. 
+<code>renderText</code> as if the function returned an expression, which is 
+clearly an error. 
 </p>
 
 <sample src="examples/UseOfReturnlessFunction.js" />
@@ -34,7 +33,7 @@ an error.
 <p>
 The program can be fixed either removing the use of the value returned by 
 <code>renderText</code>, or by changing the <code>renderText</code> method 
-to return a value.
+to return an expression.
 </p>
 
 </example>

javascript/ql/src/Statements/UseOfReturnlessFunction.ql

@@ -1,6 +1,6 @@
 /**
  * @name Use of returnless function
- * @description Using the return value of a function that does not explicitly return is indicative of a mistake.
+ * @description Using the return value of a function that does not return an expression is indicative of a mistake.
  * @kind problem
  * @problem.severity warning
  * @id js/use-of-returnless-function
@@ -15,7 +15,7 @@ import Expressions.ExprHasNoEffect
 import Statements.UselessConditional
 
 predicate returnsVoid(Function f) {
-  f.getBody() instanceof Stmt and
+  not f instanceof ArrowFunctionExpr and
   not f.isGenerator() and
   not f.isAsync() and
   not exists(f.getAReturnedExpr())

javascript/ql/src/Statements/UselessConditional.ql

@@ -124,8 +124,6 @@ predicate whitelist(Expr e) {
   isConstantBooleanReturnValue(e)
 }
 
-
-
 /**
  * Holds if `e` is part of a conditional node `cond` that evaluates
  * `e` and checks its value for truthiness.