C#: Do not extract empty locations for methods, constructors and parameters.

Author: michaelnebel

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

@@ -29,7 +29,10 @@ public override void Populate(TextWriter trapFile)
             ContainingType!.PopulateGenerics();
 
             trapFile.constructors(this, Symbol.ContainingType.Name, ContainingType, (Constructor)OriginalDefinition);
-            trapFile.constructor_location(this, Location);
+            if (Context.ExtractLocation(Symbol) && Location is not EmptyLocation)
+            {
+                trapFile.constructor_location(this, Location);
+            }
 
             if (MakeSynthetic)
             {

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

@@ -43,8 +43,16 @@ public override void Populate(TextWriter trapFile)
                 }
             }
 
-            foreach (var l in Locations)
-                trapFile.method_location(this, l);
+            if (Context.ExtractLocation(Symbol))
+            {
+                foreach (var l in Locations)
+                {
+                    if (l is not EmptyLocation)
+                    {
+                        trapFile.method_location(this, l);
+                    }
+                }
+            }
 
             PopulateGenerics(trapFile);
             Overrides(trapFile);

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

@@ -116,14 +116,24 @@ public override void Populate(TextWriter trapFile)
             trapFile.@params(this, Name, type.TypeRef, Ordinal, ParamKind, Parent!, Original);
 
             foreach (var l in Symbol.Locations)
-                trapFile.param_location(this, Context.CreateLocation(l));
+            {
+                var location = Context.CreateLocation(l);
+                if (location is not EmptyLocation)
+                {
+                    trapFile.param_location(this, location);
+                }
+            }
 
             if (!Symbol.Locations.Any() &&
                 Symbol.ContainingSymbol is IMethodSymbol ms &&
                 ms.Name == WellKnownMemberNames.TopLevelStatementsEntryPointMethodName &&
                 ms.ContainingType.Name == WellKnownMemberNames.TopLevelStatementsEntryPointTypeName)
             {
-                trapFile.param_location(this, Context.CreateLocation());
+                var location = Context.CreateLocation();
+                if (location is not EmptyLocation)
+                {
+                    trapFile.param_location(this, location);
+                }
             }
 
             if (Symbol.HasExplicitDefaultValue && Context.Defines(Symbol))
@@ -247,7 +257,6 @@ public override void Populate(TextWriter trapFile)
             var typeKey = VarargsType.Create(Context);
             // !! Maybe originaldefinition is wrong
             trapFile.@params(this, "", typeKey, Ordinal, Kind.None, Parent!, this);
-            trapFile.param_location(this, GeneratedLocation.Create(Context));
         }
 
         protected override int Ordinal => ((Method)Parent!).OriginalDefinition.Symbol.Parameters.Length;

csharp/ql/lib/semmle/code/csharp/Callable.qll

@@ -265,7 +265,13 @@ class Method extends Callable, Virtualizable, Attributable, @method {
     result = Virtualizable.super.getAnUltimateImplementor()
   }
 
-  override Location getALocation() { method_location(this, result) }
+  override Location getALocation() {
+    exists(Method m | m = this.getUnboundDeclaration() |
+      method_location(m, result)
+      or
+      not method_location(m, _) and result instanceof EmptyLocation
+    )
+  }
 
   /** Holds if this method is an extension method. */
   predicate isExtensionMethod() { this.getParameter(0).hasExtensionMethodModifier() }
@@ -357,7 +363,11 @@ class Constructor extends Callable, Member, Attributable, @constructor {
 
   override Constructor getUnboundDeclaration() { constructors(this, _, _, result) }
 
-  override Location getALocation() { constructor_location(this, result) }
+  override Location getALocation() {
+    constructor_location(this, result)
+    or
+    not constructor_location(this, _) and result instanceof EmptyLocation
+  }
 
   override predicate fromSource() { Member.super.fromSource() and not this.isCompilerGenerated() }
 

csharp/ql/lib/semmle/code/csharp/Variable.qll

@@ -213,7 +213,11 @@ class Parameter extends LocalScopeVariable, Attributable, TopLevelExprParent, @p
     params(this, _, getTypeRef(result), _, _, _, _)
   }
 
-  override Location getALocation() { param_location(this, result) }
+  override Location getALocation() {
+    param_location(this, result)
+    or
+    not param_location(this, _) and result instanceof EmptyLocation
+  }
 
   override string toString() { result = this.getName() }