Merge pull request #905 from calumgrant/cs/trivial-cil-properties

C#: Use CIL analysis when determining trivial properties

Author: hvitved

change-notes/1.20/analysis-csharp.md

@@ -26,4 +26,6 @@
 
 ## Changes to QL libraries
 
+* The class `TrivialProperty` now includes library properties determined to be trivial using CIL analysis. This may increase the number of results for all queries that use data flow.
+
 ## Changes to the autobuilder

csharp/ql/src/semmle/code/csharp/Property.qll

@@ -7,6 +7,7 @@ import Member
 import Stmt
 private import semmle.code.csharp.ExprOrStmtParent
 private import dotnet
+private import cil
 
 /**
  * A declaration that may have accessors. Either an event (`Event`), a property
@@ -495,6 +496,8 @@ class TrivialProperty extends Property {
     isAutoImplemented()
     or
     getGetter().trivialGetterField() = getSetter().trivialSetterField()
+    or
+    exists(CIL::TrivialProperty prop | this.matchesHandle(prop))
   }
 }
 

csharp/ql/test/library-tests/cil/dataflow/TrivialProperties.expected

@@ -0,0 +1,9 @@
+| System.Collections.DictionaryEntry.Key |
+| System.Collections.DictionaryEntry.Value |
+| System.Reflection.AssemblyName.CodeBase |
+| System.Reflection.AssemblyName.CultureInfo |
+| System.Reflection.AssemblyName.HashAlgorithm |
+| System.Reflection.AssemblyName.KeyPair |
+| System.Reflection.AssemblyName.Name |
+| System.Reflection.AssemblyName.Version |
+| System.Reflection.AssemblyName.VersionCompatibility |

csharp/ql/test/library-tests/cil/dataflow/TrivialProperties.ql

@@ -0,0 +1,8 @@
+import csharp
+
+from TrivialProperty prop
+where
+  prop.getDeclaringType().hasQualifiedName("System.Reflection.AssemblyName")
+  or
+  prop.getDeclaringType().hasQualifiedName("System.Collections.DictionaryEntry")
+select prop.getQualifiedName()