C#: Reduce Type Parameter- and Tuple type location extraction.

csharp/extractor/Semmle.Extraction.CSharp/Entities/Types/TupleType.cs

@@ -54,8 +54,8 @@ public override void Populate(TextWriter trapFile)
             // Note: symbol.Locations seems to be very inconsistent
             // about what locations are available for a tuple type.
             // Sometimes it's the source code, and sometimes it's empty.
-            foreach (var l in Symbol.Locations)
-                WriteLocationToTrap(trapFile.type_location, this, Context.CreateLocation(l));
+            var locations = Context.GetLocations(Symbol);
+            WriteLocationsToTrap(trapFile.type_location, this, locations);
         }
 
         private readonly Lazy<Field?[]> tupleElementsLazy;

csharp/extractor/Semmle.Extraction.CSharp/Entities/Types/TypeParameter.cs

@@ -28,10 +28,8 @@ public override void Populate(TextWriter trapFile)
 
             if (Context.ExtractLocation(Symbol))
             {
-                foreach (var l in Symbol.Locations)
-                {
-                    WriteLocationToTrap(trapFile.type_location, this, Context.CreateLocation(l));
-                }
+                var locations = Context.GetLocations(Symbol);
+                WriteLocationsToTrap(trapFile.type_location, this, locations);
             }
 
             if (IsSourceDeclaration)

csharp/extractor/Semmle.Extraction.CSharp/Extractor/Context.cs

@@ -554,6 +554,18 @@ public bool ExtractLocation(ISymbol symbol) =>
             SymbolEqualityComparer.Default.Equals(symbol, symbol.OriginalDefinition) &&
             scope.InScope(symbol);
 
+        /// <summary>
+        /// Gets the locations of the symbol that are either
+        /// (1) In assemblies.
+        /// (2) In the current context.
+        /// </summary>
+        /// <param name="symbol">The symbol</param>
+        /// <returns>List of locations</returns>
+        public IEnumerable<Entities.Location> GetLocations(ISymbol symbol) =>
+            symbol.Locations
+                .Where(l => !l.IsInSource || IsLocationInContext(l))
+                .Select(CreateLocation);
+
         public bool IsLocationInContext(Location location) =>
             location.SourceTree == SourceTree;
 

csharp/ql/lib/change-notes/2025-10-08-entity-locations.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* The extraction of location information for type parameters and tuples types has been optimized. Previously, location information was extracted multiple times for each type when it was declared across multiple files. Now, the extraction context is respected during the extraction phase, ensuring locations are only extracted within the appropriate context. This change should be transparent to end-users but may improve extraction performance in some cases.

csharp/ql/test/library-tests/locations/Base.cs

@@ -4,3 +4,5 @@ public void M() { }
 
     public class InnerBase { }
 }
+
+public abstract class Base2<T> { }

csharp/ql/test/library-tests/locations/Multiple1.cs

@@ -1 +1,13 @@
 public partial class Multiple { }
+
+public partial class MultipleGeneric<S> { }
+
+public class Multiple1Specific
+{
+    public static (int, string) M()
+    {
+        (int, string) x = (0, "");
+        (int, int) y = (0, 0);
+        return x;
+    }
+}

csharp/ql/test/library-tests/locations/Multiple2.cs

@@ -1 +1,11 @@
 public partial class Multiple { }
+
+public partial class MultipleGeneric<S> { }
+
+public class Multiple2Specific
+{
+    public void M()
+    {
+        (int, string) z = (0, "");
+    }
+}

csharp/ql/test/library-tests/locations/locations.expected

@@ -28,6 +28,8 @@ member_locations
 | Base.cs:1:23:1:29 | Base`1 | Base.cs:3:17:3:17 | M | Base.cs:3:17:3:17 | Base.cs:3:17:3:17 |
 | Base.cs:1:23:1:29 | Base`1 | Base.cs:5:18:5:26 | InnerBase | Base.cs:5:18:5:26 | Base.cs:5:18:5:26 |
 | C.cs:3:7:3:7 | C | C.cs:5:17:5:17 | M | C.cs:5:17:5:17 | C.cs:5:17:5:17 |
+| Multiple1.cs:5:14:5:30 | Multiple1Specific | Multiple1.cs:7:33:7:33 | M | Multiple1.cs:7:33:7:33 | Multiple1.cs:7:33:7:33 |
+| Multiple2.cs:5:14:5:30 | Multiple2Specific | Multiple2.cs:7:17:7:17 | M | Multiple2.cs:7:17:7:17 | Multiple2.cs:7:17:7:17 |
 | Sub.cs:1:14:1:16 | Sub | Sub.cs:3:17:3:20 | SubM | Sub.cs:3:17:3:20 | Sub.cs:3:17:3:20 |
 accessor_location
 | A.cs:3:23:3:26 | A<Int32> | A.cs:5:30:5:32 | get_Prop | A.cs:5:30:5:32 | A.cs:5:30:5:32 |
@@ -67,11 +69,22 @@ type_location
 | Base.cs:1:28:1:28 | T | Base.cs:1:28:1:28 | Base.cs:1:28:1:28 |
 | Base.cs:5:18:5:26 | InnerBase | Base.cs:5:18:5:26 | Base.cs:5:18:5:26 |
 | Base.cs:5:18:5:26 | InnerBase | Base.cs:5:18:5:26 | Base.cs:5:18:5:26 |
+| Base.cs:8:23:8:30 | Base2`1 | Base.cs:8:23:8:30 | Base.cs:8:23:8:30 |
+| Base.cs:8:29:8:29 | T | Base.cs:8:29:8:29 | Base.cs:8:29:8:29 |
 | C.cs:3:7:3:7 | C | C.cs:3:7:3:7 | C.cs:3:7:3:7 |
 | Multiple1.cs:1:22:1:29 | Multiple | Multiple1.cs:1:22:1:29 | Multiple1.cs:1:22:1:29 |
 | Multiple1.cs:1:22:1:29 | Multiple | Multiple2.cs:1:22:1:29 | Multiple2.cs:1:22:1:29 |
+| Multiple1.cs:3:22:3:39 | MultipleGeneric`1 | Multiple1.cs:3:22:3:39 | Multiple1.cs:3:22:3:39 |
+| Multiple1.cs:3:22:3:39 | MultipleGeneric`1 | Multiple2.cs:3:22:3:39 | Multiple2.cs:3:22:3:39 |
+| Multiple1.cs:3:38:3:38 | S | Multiple1.cs:3:38:3:38 | Multiple1.cs:3:38:3:38 |
+| Multiple1.cs:5:14:5:30 | Multiple1Specific | Multiple1.cs:5:14:5:30 | Multiple1.cs:5:14:5:30 |
+| Multiple1.cs:7:19:7:31 | (Int32,String) | Multiple1.cs:7:19:7:31 | Multiple1.cs:7:19:7:31 |
+| Multiple1.cs:10:9:10:18 | (Int32,Int32) | Multiple1.cs:10:9:10:18 | Multiple1.cs:10:9:10:18 |
 | Multiple2.cs:1:22:1:29 | Multiple | Multiple1.cs:1:22:1:29 | Multiple1.cs:1:22:1:29 |
 | Multiple2.cs:1:22:1:29 | Multiple | Multiple2.cs:1:22:1:29 | Multiple2.cs:1:22:1:29 |
+| Multiple2.cs:3:22:3:39 | MultipleGeneric`1 | Multiple1.cs:3:22:3:39 | Multiple1.cs:3:22:3:39 |
+| Multiple2.cs:3:22:3:39 | MultipleGeneric`1 | Multiple2.cs:3:22:3:39 | Multiple2.cs:3:22:3:39 |
+| Multiple2.cs:5:14:5:30 | Multiple2Specific | Multiple2.cs:5:14:5:30 | Multiple2.cs:5:14:5:30 |
 | Sub.cs:1:14:1:16 | Sub | Sub.cs:1:14:1:16 | Sub.cs:1:14:1:16 |
 calltype_location
 | A.cs:12:14:12:15 | call to constructor A | A.cs:3:23:3:26 | A<String> | A.cs:3:23:3:26 | A.cs:3:23:3:26 |
@@ -81,3 +94,13 @@ calltype_location
 | C.cs:9:17:9:24 | object creation of type A2 | A.cs:12:14:12:15 | A2 | A.cs:12:14:12:15 | A.cs:12:14:12:15 |
 | Sub.cs:1:14:1:16 | call to constructor Base | Base.cs:1:23:1:29 | Base<Int32> | Base.cs:1:23:1:29 | Base.cs:1:23:1:29 |
 | Sub.cs:6:17:6:31 | object creation of type InnerBase | Base.cs:5:18:5:26 | InnerBase | Base.cs:5:18:5:26 | Base.cs:5:18:5:26 |
+typeparameter_location
+| A.cs:3:25:3:25 | T | A.cs:3:25:3:25 | A.cs:3:25:3:25 |
+| Base.cs:1:28:1:28 | T | Base.cs:1:28:1:28 | Base.cs:1:28:1:28 |
+| Base.cs:8:29:8:29 | T | Base.cs:8:29:8:29 | Base.cs:8:29:8:29 |
+| Multiple1.cs:3:38:3:38 | S | Multiple1.cs:3:38:3:38 | Multiple1.cs:3:38:3:38 |
+| Multiple1.cs:3:38:3:38 | S | Multiple2.cs:3:38:3:38 | Multiple2.cs:3:38:3:38 |
+tupletype_location
+| Multiple1.cs:7:19:7:31 | (Int32,String) | Multiple1.cs:7:19:7:31 | Multiple1.cs:7:19:7:31 |
+| Multiple1.cs:7:19:7:31 | (Int32,String) | Multiple2.cs:9:9:9:21 | Multiple2.cs:9:9:9:21 |
+| Multiple1.cs:10:9:10:18 | (Int32,Int32) | Multiple1.cs:10:9:10:18 | Multiple1.cs:10:9:10:18 |

csharp/ql/test/library-tests/locations/locations.ql

@@ -4,7 +4,8 @@ query predicate member_locations(Type t, Member m, SourceLocation l) {
   t = m.getDeclaringType() and
   l = m.getLocation() and
   not l instanceof EmptyLocation and
-  not m instanceof Constructor
+  not m instanceof Constructor and
+  t.fromSource()
 }
 
 query predicate accessor_location(Type t, Accessor a, SourceLocation l) {
@@ -21,3 +22,7 @@ query predicate calltype_location(Call call, Type t, SourceLocation l) {
   t = call.getType() and
   l = t.getALocation()
 }
+
+query predicate typeparameter_location(TypeParameter tp, SourceLocation l) { tp.getALocation() = l }
+
+query predicate tupletype_location(TupleType tt, SourceLocation l) { tt.getALocation() = l }