C#: Add namespace_access_expr because of nameof(Namespace)

Author: calumgrant

csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Access.cs

@@ -33,6 +33,9 @@ static ExprKind AccessKind(Context cx, ISymbol symbol)
                 case SymbolKind.Parameter:
                     return ExprKind.PARAMETER_ACCESS;
 
+                case SymbolKind.Namespace:
+                    return ExprKind.NAMESPACE_ACCESS;
+
                 default:
                     cx.ModelError(symbol, $"Unhandled access kind '{symbol.Kind}'");
                     return ExprKind.UNKNOWN;

csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Name.cs

@@ -59,6 +59,9 @@ public static Expression Create(ExpressionNodeInfo info)
                 case SymbolKind.Parameter:
                     return Access.Create(info, target, false, Parameter.GetAlreadyCreated(info.Context, (IParameterSymbol)target));
 
+                case SymbolKind.Namespace:
+                    return Access.Create(info, target, false, Namespace.Create(info.Context, (INamespaceSymbol)target));
+
                 default:
                     throw new InternalError(info.Node, $"Unhandled identifier kind '{target.Kind}'");
             }

csharp/extractor/Semmle.Extraction.CSharp/Kinds/ExprKind.cs

@@ -114,6 +114,7 @@ public enum ExprKind
         POSITIONAL_PATTERN = 117,
         SWITCH_CASE = 118,
         ASSIGN_COALESCE = 119,
-        SUPPRESS_NULLABLE_WARNING = 120
+        SUPPRESS_NULLABLE_WARNING = 120,
+        NAMESPACE_ACCESS = 121
     }
 }

csharp/ql/src/semmlecode.csharp.dbscheme

@@ -214,7 +214,7 @@ tokens(
          | @using_directive | @type_parameter_constraints | @external_element
          | @xmllocatable | @asp_element | @namespace;
 
-@declaration = @callable | @generic | @assignable;
+@declaration = @callable | @generic | @assignable | @namespace;
 
 @named_element = @namespace | @declaration;
 
@@ -982,6 +982,7 @@ case @expr.kind of
 | 118 = @switch_case_expr
 | 119 = @assign_coalesce_expr
 | 120 = @suppress_nullable_warning_expr
+| 121 = @namespace_access_expr
 ;
 
 @switch = @switch_stmt | @switch_expr;
@@ -1004,7 +1005,7 @@ case @expr.kind of
 
 @member_access_expr = @field_access_expr | @property_access_expr | @indexer_access_expr | @event_access_expr
                     | @method_access_expr | @type_access_expr | @dynamic_member_access_expr;
-@access_expr = @member_access_expr | @this_access_expr | @base_access_expr | @assignable_access_expr;
+@access_expr = @member_access_expr | @this_access_expr | @base_access_expr | @assignable_access_expr | @namespace_access_expr;
 @element_access_expr = @indexer_access_expr | @array_access_expr | @dynamic_element_access_expr;
 
 @local_variable_access = @local_variable_access_expr | @local_var_decl_expr;
@@ -1084,7 +1085,7 @@ expr_access(
   unique int accesser_id: @access_expr ref,
   int target_id: @accessible ref);
 
-@accessible = @method | @assignable | @local_function;
+@accessible = @method | @assignable | @local_function | @namespace;
 
 expr_location(
   unique int id: @expr ref,

csharp/ql/src/semmlecode.csharp.dbscheme.stats

@@ -760,6 +760,10 @@
 <v>7589</v>
 </e>
 <e>
+<k>@namespace_access_expr</k>
+<v>1000</v>
+</e>
+<e>
 <k>@interpolated_string_expr</k>
 <v>3470</v>
 </e>

csharp/ql/test/library-tests/regressions/Program.cs

@@ -164,4 +164,9 @@ unsafe class ArrayTypesTest
   int*[][] field;
 }
 
+class NameofNamespace
+{
+    string s = nameof(System);
+}
+
 // semmle-extractor-options: /r:System.Dynamic.Runtime.dll

csharp/ql/test/library-tests/regressions/TypeMentions.expected

@@ -79,3 +79,4 @@
 | Program.cs:164:3:164:5 | Int32 |
 | Program.cs:164:3:164:6 | Int32* |
 | Program.cs:164:3:164:10 | Int32*[][] |
+| Program.cs:169:5:169:10 | String |