Merge pull request #16104 from hvitved/csharp/more-compiler-generated

C#: Mark more expressions as compiler generated

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

@@ -32,7 +32,10 @@ private predicate shouldPrint(Element e, Location l) {
 }
 
 private predicate isImplicitExpression(ControlFlowElement element) {
-  element.(Expr).isImplicit() and not exists(element.getAChild())
+  element.(Expr).isImplicit() and
+  not element instanceof CastExpr and
+  not element.(OperatorCall).getTarget() instanceof ImplicitConversionOperator and
+  not element instanceof ElementInitializer
 }
 
 private predicate isFilteredCompilerGenerated(Declaration d) {
@@ -291,18 +294,6 @@ class ControlFlowElementNode extends ElementNode {
     controlFlowElement = element and
     // Removing implicit expressions
     not isImplicitExpression(element) and
-    // Removing extra nodes that are generated for an `AssignOperation`
-    not exists(AssignOperation ao |
-      ao.hasExpandedAssignment() and
-      (
-        ao.getExpandedAssignment() = controlFlowElement or
-        ao.getExpandedAssignment().getRValue() = controlFlowElement or
-        ao.getExpandedAssignment().getRValue().(BinaryOperation).getLeftOperand() =
-          controlFlowElement.getParent*() or
-        ao.getExpandedAssignment().getRValue().(OperatorCall).getChild(0) =
-          controlFlowElement.getParent*()
-      )
-    ) and
     not isNotNeeded(element.getParent+()) and
     // LambdaExpr is both a Callable and a ControlFlowElement,
     // print it with the more specific CallableNode
@@ -429,7 +420,7 @@ final class DeclarationWithAccessorsNode extends ElementNode {
     result.(ParametersNode).getParameterizable() = declaration
     or
     childIndex = 2 and
-    result.(ElementNode).getElement() = declaration.(Property).getInitializer().getParent()
+    result.(ElementNode).getElement() = declaration.(Property).getInitializer()
     or
     result.(ElementNode).getElement() =
       rank[childIndex - 2](Element a, string file, int line, int column, string name |
@@ -462,12 +453,7 @@ final class FieldNode extends ElementNode {
     result.(AttributesNode).getAttributable() = field
     or
     childIndex = 1 and
-    field.hasInitializer() and
-    (
-      if field.getDeclaringType() instanceof Enum
-      then result.(ElementNode).getElement() = field.getInitializer()
-      else result.(ElementNode).getElement() = field.getInitializer().getParent()
-    )
+    result.(ElementNode).getElement() = field.getInitializer()
   }
 }
 

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

@@ -408,7 +408,7 @@ class Field extends Variable, AssignableMember, Attributable, TopLevelExprParent
    * }
    * ```
    */
-  override Expr getInitializer() { result = this.getChildExpr(0).getChildExpr(0) }
+  final override Expr getInitializer() { result = this.getChildExpr(0).getChildExpr(0) }
 
   /**
    * Holds if this field has an initial value. For example, the initial
@@ -515,6 +515,4 @@ class EnumConstant extends MemberConstant {
    * ```
    */
   predicate hasExplicitValue() { exists(this.getInitializer()) }
-
-  override Expr getInitializer() { result = this.getChildExpr(0) }
 }

csharp/ql/lib/semmle/code/csharp/exprs/Expr.qll

@@ -67,7 +67,11 @@ class Expr extends ControlFlowElement, @expr {
    * Holds if this expression is generated by the compiler and does not appear
    * explicitly in the source code.
    */
-  predicate isImplicit() { compiler_generated(this) }
+  final predicate isImplicit() {
+    compiler_generated(this) or
+    this =
+      any(AssignOperation op).getExpandedAssignment().getRValue().getChildExpr(0).getAChildExpr+()
+  }
 
   /**
    * Gets an expression that is the result of stripping (recursively) all