Ruby: simplify some charpreds

Author: alexrford

ruby/ql/lib/codeql/ruby/frameworks/ActionController.qll

@@ -127,7 +127,7 @@ abstract class ParamsCall extends MethodCall {
  * ActionController parameters available via the `params` method.
  */
 class ParamsSource extends RemoteFlowSource::Range {
-  ParamsSource() { exists(ParamsCall call | this.asExpr().getExpr() = call) }
+  ParamsSource() { this.asExpr().getExpr() instanceof ParamsCall }
 
   override string getSourceType() { result = "ActionController::Metal#params" }
 }
@@ -144,7 +144,7 @@ abstract class CookiesCall extends MethodCall {
  * ActionController parameters available via the `cookies` method.
  */
 class CookiesSource extends RemoteFlowSource::Range {
-  CookiesSource() { exists(CookiesCall call | this.asExpr().getExpr() = call) }
+  CookiesSource() { this.asExpr().getExpr() instanceof CookiesCall }
 
   override string getSourceType() { result = "ActionController::Metal#cookies" }
 }

ruby/ql/lib/codeql/ruby/frameworks/core/Kernel.qll

@@ -19,19 +19,14 @@ module Kernel {
    */
   class KernelMethodCall extends DataFlow::CallNode {
     KernelMethodCall() {
-      exists(MethodCall methodCall |
-        methodCall = this.asExpr().getExpr() and
-        (
-          this = API::getTopLevelMember("Kernel").getAMethodCall(_)
-          or
-          methodCall instanceof UnknownMethodCall and
-          (
-            this.getReceiver().asExpr().getExpr() instanceof SelfVariableAccess and
-            isPrivateKernelMethod(methodCall.getMethodName())
-            or
-            isPublicKernelMethod(methodCall.getMethodName())
-          )
-        )
+      this = API::getTopLevelMember("Kernel").getAMethodCall(_)
+      or
+      this.asExpr().getExpr() instanceof UnknownMethodCall and
+      (
+        this.getReceiver().asExpr().getExpr() instanceof SelfVariableAccess and
+        isPrivateKernelMethod(this.getMethodName())
+        or
+        isPublicKernelMethod(this.getMethodName())
       )
     }
   }