C#: Improve arg-param mapping logic to consider named arguments passed to params parameters

tamasvajk · tamasvajk · commit 7daeeef3a1d9 · 2024-01-08T10:00:39.000+01:00
diff --git a/csharp/ql/lib/semmle/code/csharp/exprs/Call.qll b/csharp/ql/lib/semmle/code/csharp/exprs/Call.qll
@@ -66,8 +66,7 @@ class Call extends DotNet::Call, Expr, @call {
       result = this.getImplicitArgument(p)
       or
       // Appears in the named part of the call
-      result = this.getExplicitArgument(p.getName()) and
-      (p.(Parameter).isParams() implies isValidExplicitParamsType(p, result.getType()))
+      result = this.getExplicitArgument(p.getName())
     )
   }
 
@@ -224,28 +223,6 @@ class Call extends DotNet::Call, Expr, @call {
   override string toString() { result = "call" }
 }
 
-/**
- * Holds if the type `t` is a valid argument type for passing an explicit array
- * to the `params` parameter `p`. For example, the types `object[]` and `string[]`
- * of the arguments on lines 4 and 5, respectively, are valid for the parameter
- * `args` on line 1 in
- *
- * ```csharp
- * void M(params object[] args) { ... }
- *
- * void CallM(object[] os, string[] ss, string s) {
- *   M(os);
- *   M(ss);
- *   M(s);
- * }
- * ```
- */
-pragma[nomagic]
-private predicate isValidExplicitParamsType(Parameter p, Type t) {
-  p.isParams() and
-  t.isImplicitlyConvertibleTo(p.getType())
-}
-
 /**
  * A method call, for example `a.M()` on line 5 in
  *
diff --git a/csharp/ql/test/library-tests/arguments/argumentByName.expected b/csharp/ql/test/library-tests/arguments/argumentByName.expected
@@ -12,6 +12,7 @@
 | arguments.cs:35:9:35:19 | call to method f3 | arguments.cs:35:18:35:18 | 2 | args |
 | arguments.cs:36:9:36:33 | call to method f3 | arguments.cs:36:12:36:12 | 0 | o |
 | arguments.cs:36:9:36:33 | call to method f3 | arguments.cs:36:15:36:32 | array creation of type Int32[] | args |
+| arguments.cs:37:9:37:25 | call to method f3 | arguments.cs:37:18:37:18 | 1 | args |
 | arguments.cs:37:9:37:25 | call to method f3 | arguments.cs:37:24:37:24 | 0 | o |
 | arguments.cs:38:9:38:19 | call to method f3 | arguments.cs:38:12:38:12 | 0 | o |
 | arguments.cs:38:9:38:19 | call to method f3 | arguments.cs:38:15:38:18 | access to parameter args | args |
diff --git a/csharp/ql/test/library-tests/arguments/argumentByParameter.expected b/csharp/ql/test/library-tests/arguments/argumentByParameter.expected
@@ -12,6 +12,7 @@
 | arguments.cs:35:9:35:19 | call to method f3 | arguments.cs:35:18:35:18 | 2 | arguments.cs:33:33:33:36 | args |
 | arguments.cs:36:9:36:33 | call to method f3 | arguments.cs:36:12:36:12 | 0 | arguments.cs:33:17:33:17 | o |
 | arguments.cs:36:9:36:33 | call to method f3 | arguments.cs:36:15:36:32 | array creation of type Int32[] | arguments.cs:33:33:33:36 | args |
+| arguments.cs:37:9:37:25 | call to method f3 | arguments.cs:37:18:37:18 | 1 | arguments.cs:33:33:33:36 | args |
 | arguments.cs:37:9:37:25 | call to method f3 | arguments.cs:37:24:37:24 | 0 | arguments.cs:33:17:33:17 | o |
 | arguments.cs:38:9:38:19 | call to method f3 | arguments.cs:38:12:38:12 | 0 | arguments.cs:33:17:33:17 | o |
 | arguments.cs:38:9:38:19 | call to method f3 | arguments.cs:38:15:38:18 | access to parameter args | arguments.cs:33:33:33:36 | args |
diff --git a/csharp/ql/test/library-tests/arguments/parameterGetArguments.expected b/csharp/ql/test/library-tests/arguments/parameterGetArguments.expected
@@ -17,6 +17,7 @@
 | arguments.cs:33:33:33:36 | args | arguments.cs:35:15:35:15 | 1 |
 | arguments.cs:33:33:33:36 | args | arguments.cs:35:18:35:18 | 2 |
 | arguments.cs:33:33:33:36 | args | arguments.cs:36:15:36:32 | array creation of type Int32[] |
+| arguments.cs:33:33:33:36 | args | arguments.cs:37:18:37:18 | 1 |
 | arguments.cs:33:33:33:36 | args | arguments.cs:38:15:38:18 | access to parameter args |
 | arguments.cs:33:33:33:36 | args | arguments.cs:39:18:39:21 | access to parameter args |
 | arguments.cs:33:33:33:36 | args | arguments.cs:40:18:40:35 | array creation of type Int32[] |
