C++: Factored the body of TooFewArguments.ql out into a library file

cpp/ql/src/Likely Bugs/Underspecified Functions/TooFewArguments.ql

@@ -15,31 +15,8 @@
  */
 
 import cpp
-
-// True if function was ()-declared, but not (void)-declared or K&R-defined
-predicate hasZeroParamDecl(Function f) {
-  exists(FunctionDeclarationEntry fde | fde = f.getADeclarationEntry() |
-    not fde.hasVoidParamList() and fde.getNumberOfParameters() = 0 and not fde.isDefinition()
-  )
-}
-
-// True if this file (or header) was compiled as a C file
-predicate isCompiledAsC(File f) {
-  f.compiledAsC()
-  or
-  exists(File src | isCompiledAsC(src) | src.getAnIncludedFile() = f)
-}
+import TooFewArguments
 
 from FunctionCall fc, Function f
-where
-  f = fc.getTarget() and
-  not f.isVarargs() and
-  not f instanceof BuiltInFunction and
-  hasZeroParamDecl(f) and
-  isCompiledAsC(f.getFile()) and
-  // There is an explicit declaration of the function whose parameter count is larger
-  // than the number of call arguments
-  exists(FunctionDeclarationEntry fde | fde = f.getADeclarationEntry() |
-    fde.getNumberOfParameters() > fc.getNumberOfArguments()
-  )
+where tooFewArguments(fc, f)
 select fc, "This call has fewer arguments than required by $@.", f, f.toString()

cpp/ql/src/Likely Bugs/Underspecified Functions/TooFewArguments.qll

@@ -0,0 +1,34 @@
+/**
+ * Provides the implementation of the TooFewArguments query. The
+ * query is implemented as a library, so that we can avoid producing
+ * duplicate results in other similar queries.
+ */
+
+import cpp
+
+// True if function was ()-declared, but not (void)-declared or K&R-defined
+private predicate hasZeroParamDecl(Function f) {
+  exists(FunctionDeclarationEntry fde | fde = f.getADeclarationEntry() |
+    not fde.hasVoidParamList() and fde.getNumberOfParameters() = 0 and not fde.isDefinition()
+  )
+}
+
+// True if this file (or header) was compiled as a C file
+private predicate isCompiledAsC(File f) {
+  f.compiledAsC()
+  or
+  exists(File src | isCompiledAsC(src) | src.getAnIncludedFile() = f)
+}
+
+predicate tooFewArguments(FunctionCall fc, Function f) {
+  f = fc.getTarget() and
+  not f.isVarargs() and
+  not f instanceof BuiltInFunction and
+  hasZeroParamDecl(f) and
+  isCompiledAsC(f.getFile()) and
+  // There is an explicit declaration of the function whose parameter count is larger
+  // than the number of call arguments
+  exists(FunctionDeclarationEntry fde | fde = f.getADeclarationEntry() |
+    fde.getNumberOfParameters() > fc.getNumberOfArguments()
+  )
+}