Fix argument location of top level statement entry point

Author: tamasvajk

csharp/extractor/Semmle.Extraction.CSharp/Entities/Parameter.cs

@@ -112,6 +112,13 @@ public override void Populate(TextWriter trapFile)
             foreach (var l in symbol.Locations)
                 trapFile.param_location(this, Context.CreateLocation(l));
 
+            if (!symbol.Locations.Any() &&
+                symbol.ContainingSymbol is IMethodSymbol ms &&
+                ms.Name == WellKnownMemberNames.TopLevelStatementsEntryPointMethodName)
+            {
+                trapFile.param_location(this, Context.CreateLocation());
+            }
+
             if (!IsSourceDeclaration || !symbol.FromSource())
                 return;
 

csharp/ql/test/library-tests/csharp9/PrintAst.expected

@@ -392,6 +392,8 @@ FunctionPointer.cs:
 GlobalStmt.cs:
 #    7| [Class] <Program>$
 #    7|   4: [Method] <Main>$
+#-----|     2: (Parameters)
+#    1|       0: [Parameter] args
 #    7|     4: [BlockStmt] {...}
 #   11|       0: [ExprStmt] ...;
 #   11|         0: [MethodCall] call to method WriteLine

csharp/ql/test/library-tests/csharp9/globalStmt.expected

@@ -4,7 +4,7 @@ global_stmt
 | GlobalStmt.cs:13:1:13:4 | ...; |
 | GlobalStmt.cs:15:1:17:1 | M(...) |
 globalBlock
-| GlobalStmt.cs:7:1:25:1 | {...} | GlobalStmt.cs:7:1:25:1 | <Main>$ | file://:0:0:0:0 | args | GlobalStmt.cs:7:1:25:1 | <Program>$ |
+| GlobalStmt.cs:7:1:25:1 | {...} | GlobalStmt.cs:7:1:25:1 | <Main>$ | GlobalStmt.cs:1:1:1:0 | args | GlobalStmt.cs:7:1:25:1 | <Program>$ |
 methods
 | GlobalStmt.cs:7:1:25:1 | <Main>$ | entry |
 | GlobalStmt.cs:21:8:21:9 | M1 | non-entry |