diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Assignment.cs b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Assignment.cs
index f3e2e510cd64..6f6b4609f050 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Assignment.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Assignment.cs
@@ -23,15 +23,12 @@ public static Assignment Create(ExpressionNodeInfo info)
         protected override void PopulateExpression(TextWriter trapFile)
         {
             var operatorKind = OperatorKind;
+            // TODO: THIS CHECK CAN BE SIMPLIFIED - As we now always consider this to be an operator invocation.
             if (operatorKind.HasValue)
             {
-                // Convert assignment such as `a += b` into `a = a + b`.
-                var simpleAssignExpr = new Expression(new ExpressionInfo(Context, Type, Location, ExprKind.SIMPLE_ASSIGN, this, 2, isCompilerGenerated: true, null));
-                Create(Context, Syntax.Left, simpleAssignExpr, 1);
-                var opexpr = new Expression(new ExpressionInfo(Context, Type, Location, operatorKind.Value, simpleAssignExpr, 0, isCompilerGenerated: true, null));
-                Create(Context, Syntax.Left, opexpr, 0, isCompilerGenerated: true);
-                Create(Context, Syntax.Right, opexpr, 1);
-                opexpr.OperatorCall(trapFile, Syntax);
+                Create(Context, Syntax.Left, this, 0);
+                Create(Context, Syntax.Right, this, 1);
+                OperatorCall(trapFile, Syntax);
             }
             else
             {
diff --git a/csharp/ql/lib/semmle/code/csharp/Assignable.qll b/csharp/ql/lib/semmle/code/csharp/Assignable.qll
index 3c7170a6f846..e4cf08282f3c 100644
--- a/csharp/ql/lib/semmle/code/csharp/Assignable.qll
+++ b/csharp/ql/lib/semmle/code/csharp/Assignable.qll
@@ -78,6 +78,8 @@ class AssignableRead extends AssignableAccess {
       this.isRefArgument()
       or
       this = any(AssignableDefinitions::AddressOfDefinition def).getTargetAccess()
+      or
+      this = any(AssignableDefinitions::AssignOperationDefinition def).getTargetAccess()
     ) and
     not nameOfChild(_, this)
   }
@@ -271,6 +273,8 @@ module AssignableInternal {
     def = TAddressOfDefinition(result)
     or
     def = TPatternDefinition(result)
+    or
+    def = TAssignOperationDefinition(result)
   }
 
   /** A local variable declaration at the top-level of a pattern. */
@@ -286,7 +290,10 @@ module AssignableInternal {
   private module Cached {
     cached
     newtype TAssignableDefinition =
-      TAssignmentDefinition(Assignment a) { not a.getLValue() instanceof TupleExpr } or
+      TAssignmentDefinition(Assignment a) {
+        not a.getLValue() instanceof TupleExpr and
+        not a instanceof AssignOperation
+      } or
       TTupleAssignmentDefinition(AssignExpr ae, Expr leaf) { tupleAssignmentDefinition(ae, leaf) } or
       TOutRefDefinition(AssignableAccess aa) {
         aa.isOutArgument()
@@ -309,7 +316,8 @@ module AssignableInternal {
         )
       } or
       TAddressOfDefinition(AddressOfExpr aoe) or
-      TPatternDefinition(TopLevelPatternDecl tlpd)
+      TPatternDefinition(TopLevelPatternDecl tlpd) or
+      TAssignOperationDefinition(AssignOperation ao)
 
     /**
      * Gets the source expression assigned in tuple definition `def`, if any.
@@ -355,6 +363,8 @@ module AssignableInternal {
       def = TMutationDefinition(any(MutatorOperation mo | mo.getOperand() = result))
       or
       def = TAddressOfDefinition(any(AddressOfExpr aoe | aoe.getOperand() = result))
+      or
+      def = TAssignOperationDefinition(any(AssignOperation ao | ao.getLeftOperand() = result))
     }
 
     /**
@@ -369,7 +379,7 @@ module AssignableInternal {
       or
       exists(Assignment ass | ac = ass.getLValue() |
         result = ass.getRValue() and
-        not ass.(AssignOperation).hasExpandedAssignment()
+        not ass instanceof AssignOperation
       )
     }
   }
@@ -388,8 +398,9 @@ private import AssignableInternal
  * a mutation update (`AssignableDefinitions::MutationDefinition`), a local variable
  * declaration without an initializer (`AssignableDefinitions::LocalVariableDefinition`),
  * an implicit parameter definition (`AssignableDefinitions::ImplicitParameterDefinition`),
- * an address-of definition (`AssignableDefinitions::AddressOfDefinition`), or a pattern
- * definition (`AssignableDefinitions::PatternDefinition`).
+ * an address-of definition (`AssignableDefinitions::AddressOfDefinition`), a pattern
+ * definition (`AssignableDefinitions::PatternDefinition`), or a compound assignment
+ * operation definition (`AssignableDefinitions::AssignOperationDefinition`)
  */
 class AssignableDefinition extends TAssignableDefinition {
   /**
@@ -511,7 +522,7 @@ module AssignableDefinitions {
 
     override Expr getSource() {
       result = a.getRValue() and
-      not a instanceof AssignOperation
+      not a instanceof AddOrRemoveEventExpr
     }
 
     override string toString() { result = a.toString() }
@@ -735,4 +746,17 @@ module AssignableDefinitions {
     /** Gets the assignable (field or property) being initialized. */
     Assignable getAssignable() { result = fieldOrProp }
   }
+
+  /**
+   * A definition by a compound assignment operation, for example `x += y`.
+   */
+  class AssignOperationDefinition extends AssignableDefinition, TAssignOperationDefinition {
+    AssignOperation ao;
+
+    AssignOperationDefinition() { this = TAssignOperationDefinition(ao) }
+
+    override Expr getSource() { result = ao }
+
+    override string toString() { result = ao.toString() }
+  }
 }
diff --git a/csharp/ql/lib/semmle/code/csharp/ExprOrStmtParent.qll b/csharp/ql/lib/semmle/code/csharp/ExprOrStmtParent.qll
index aa834ef91038..3ce937316a84 100644
--- a/csharp/ql/lib/semmle/code/csharp/ExprOrStmtParent.qll
+++ b/csharp/ql/lib/semmle/code/csharp/ExprOrStmtParent.qll
@@ -20,7 +20,7 @@ class ExprOrStmtParent extends Element, @exprorstmt_parent {
 
   /** Gets the `i`th child expression of this element (zero-based). */
   final Expr getChildExpr(int i) {
-    expr_parent_adjusted(result, i, this) or
+    expr_parent(result, i, this) or
     expr_parent_top_level_adjusted(result, i, this)
   }
 
@@ -119,66 +119,14 @@ private module Cached {
   }
 
   /**
-   * The `expr_parent()` relation adjusted for expandable assignments. For example,
-   * the assignment `x += y` is extracted as
-   *
-   * ```
-   *          +=
-   *           |
-   *           2
-   *           |
-   *           =
-   *          / \
-   *         1   0
-   *        /     \
-   *       x       +
-   *              / \
-   *             1   0
-   *            /     \
-   *           x       y
-   * ```
-   *
-   * in order to be able to retrieve the expanded assignment `x = x + y` as the 2nd
-   * child. This predicate changes the diagram above into
-   *
-   * ```
-   *          +=
-   *         /  \
-   *        1    0
-   *       /      \
-   *      x        y
-   * ```
+   * Use `expr_parent` instead.
    */
   cached
-  predicate expr_parent_adjusted(Expr child, int i, ControlFlowElement parent) {
-    if parent instanceof AssignOperation
-    then
-      parent =
-        any(AssignOperation ao |
-          exists(AssignExpr ae | ae = ao.getExpandedAssignment() |
-            i = 0 and
-            exists(Expr right |
-              // right = `x + y`
-              expr_parent(right, 0, ae)
-            |
-              expr_parent(child, 1, right)
-            )
-            or
-            i = 1 and
-            expr_parent(child, 1, ae)
-          )
-          or
-          not ao.hasExpandedAssignment() and
-          expr_parent(child, i, parent)
-        )
-    else expr_parent(child, i, parent)
-  }
+  deprecated predicate expr_parent_adjusted(Expr child, int i, ControlFlowElement parent) { none() }
 
   private Expr getAChildExpr(ExprOrStmtParent parent) {
     result = parent.getAChildExpr() and
     not result = parent.(DeclarationWithGetSetAccessors).getExpressionBody()
-    or
-    result = parent.(AssignOperation).getExpandedAssignment()
   }
 
   private ControlFlowElement getAChild(ExprOrStmtParent parent) {
diff --git a/csharp/ql/lib/semmle/code/csharp/commons/Strings.qll b/csharp/ql/lib/semmle/code/csharp/commons/Strings.qll
index bdf9e5585394..f2d39f9dcc7c 100644
--- a/csharp/ql/lib/semmle/code/csharp/commons/Strings.qll
+++ b/csharp/ql/lib/semmle/code/csharp/commons/Strings.qll
@@ -49,6 +49,16 @@ class ImplicitToStringExpr extends Expr {
       this = add.getOtherOperand(o).stripImplicit()
     )
     or
+    // s1 += s2 for where the left hand side is a string, call an operator +(string, object)
+    exists(AssignAddExpr add, Operator o, Parameter p0, Parameter p1 |
+      o = add.getTarget() and
+      o.getName() = "+" and
+      p0 = o.getParameter(0) and
+      p1 = o.getParameter(1) and
+      p0.getType() instanceof StringType and
+      this = getAnAssignedArgumentOrParam(p1).stripImplicit()
+    )
+    or
     this = any(InterpolatedStringExpr ise).getAnInsert().stripImplicit()
   }
 }
diff --git a/csharp/ql/lib/semmle/code/csharp/controlflow/internal/ControlFlowGraphImpl.qll b/csharp/ql/lib/semmle/code/csharp/controlflow/internal/ControlFlowGraphImpl.qll
index 1696869e5911..ea3007e3a839 100644
--- a/csharp/ql/lib/semmle/code/csharp/controlflow/internal/ControlFlowGraphImpl.qll
+++ b/csharp/ql/lib/semmle/code/csharp/controlflow/internal/ControlFlowGraphImpl.qll
@@ -89,18 +89,13 @@ class CfgScope extends Element, @top_level_exprorstmt_parent {
 
 private class TAstNode = @callable or @control_flow_element;
 
-private Element getAChild(Element p) {
-  result = p.getAChild() or
-  result = p.(AssignOperation).getExpandedAssignment()
-}
-
 pragma[nomagic]
 private predicate astNode(Element e) {
   e = any(@top_level_exprorstmt_parent p | not p instanceof Attribute)
   or
   exists(Element parent |
     astNode(parent) and
-    e = getAChild(parent)
+    e = parent.getAChild()
   )
 }
 
@@ -486,6 +481,7 @@ module Expressions {
         result = qe.getChild(i)
       )
     or
+    // TODO: This can be fixed if the extracted indexes are fixed.
     e =
       any(Assignment a |
         // The left-hand side of an assignment is evaluated before the right-hand side
@@ -520,7 +516,6 @@ module Expressions {
       not this instanceof LogicalOrExpr and
       not this instanceof NullCoalescingExpr and
       not this instanceof ConditionalExpr and
-      not this instanceof AssignOperationWithExpandedAssignment and
       not this instanceof ConditionallyQualifiedExpr and
       not this instanceof ThrowExpr and
       not this instanceof ObjectCreation and
@@ -618,7 +613,7 @@ module Expressions {
       def.getExpr() = this and
       def.getTargetAccess().(WriteAccess) instanceof QualifiableExpr and
       not def instanceof AssignableDefinitions::OutRefDefinition and
-      not this instanceof AssignOperationWithExpandedAssignment
+      not def instanceof AssignableDefinitions::AssignOperationDefinition
     }
 
     /**
@@ -801,26 +796,6 @@ module Expressions {
     }
   }
 
-  /**
-   * An assignment operation that has an expanded version. We use the expanded
-   * version in the control flow graph in order to get better data flow / taint
-   * tracking.
-   */
-  private class AssignOperationWithExpandedAssignment extends ControlFlowTree instanceof AssignOperation
-  {
-    private Expr expanded;
-
-    AssignOperationWithExpandedAssignment() { expanded = this.getExpandedAssignment() }
-
-    final override predicate first(AstNode first) { first(expanded, first) }
-
-    final override predicate last(AstNode last, Completion c) { last(expanded, last, c) }
-
-    final override predicate propagatesAbnormal(AstNode child) { none() }
-
-    final override predicate succ(AstNode pred, AstNode succ, Completion c) { none() }
-  }
-
   /** A conditionally qualified expression. */
   private class ConditionallyQualifiedExpr extends PostOrderTree instanceof QualifiableExpr {
     private Expr qualifier;
@@ -1578,7 +1553,7 @@ module Statements {
   /** Gets a child of `cfe` that is in CFG scope `scope`. */
   pragma[noinline]
   private ControlFlowElement getAChildInScope(AstNode cfe, Callable scope) {
-    result = getAChild(cfe) and
+    result = cfe.getAChild() and
     scope = result.getEnclosingCallable()
   }
 
diff --git a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowPrivate.qll b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowPrivate.qll
index 70161a6fc477..b5be9582c6b6 100644
--- a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowPrivate.qll
+++ b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowPrivate.qll
@@ -1579,6 +1579,19 @@ private module ArgumentNodes {
           scope = def.getExpr()
         )
       else scope = e2
+      or
+      e1.(Argument).isArgumentOf(e2, _) and
+      (
+        e2 instanceof DynamicMemberAccess or
+        e2 instanceof DynamicElementAccess
+      ) and
+      exists(AssignableDefinitions::AssignOperationDefinition def |
+        def.getTargetAccess() = e2 and
+        def.getExpr() = e1
+      ) and
+      exactScope = false and
+      isSuccessor = false and
+      scope = e1
     }
   }
 
diff --git a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/TaintTrackingPrivate.qll b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/TaintTrackingPrivate.qll
index bb08c8f7e2ca..3f0090d4791c 100644
--- a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/TaintTrackingPrivate.qll
+++ b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/TaintTrackingPrivate.qll
@@ -60,6 +60,9 @@ private class LocalTaintExprStepConfiguration extends ControlFlowReachabilityCon
       e1 = e2.(AddExpr).getAnOperand() and
       scope = e2
       or
+      e1 = e2.(AssignAddExpr).getAnOperand() and
+      scope = e2
+      or
       // A comparison expression where taint can flow from one of the
       // operands if the other operand is a constant value.
       exists(ComparisonTest ct, Expr other |
diff --git a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/RangeUtils.qll b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/RangeUtils.qll
index 71d177a48bb1..edfd7914088b 100644
--- a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/RangeUtils.qll
+++ b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/RangeUtils.qll
@@ -33,7 +33,9 @@ private module Impl {
   /** Holds if SSA definition `def` equals `e + delta`. */
   predicate ssaUpdateStep(ExplicitDefinition def, ExprNode e, int delta) {
     exists(ControlFlow::Node cfn | cfn = def.getControlFlowNode() |
-      e = cfn.(ExprNode::Assignment).getRValue() and delta = 0
+      e = cfn.(ExprNode::Assignment).getRValue() and
+      delta = 0 and
+      not cfn instanceof ExprNode::AssignOperation
       or
       e = cfn.(ExprNode::PostIncrExpr).getOperand() and delta = 1
       or
@@ -66,6 +68,12 @@ private module Impl {
       x.getIntValue() = delta
     )
     or
+    exists(ConstantIntegerExpr x |
+      e2.(ExprNode::AssignAddExpr).getLeftOperand() = e1 and
+      e2.(ExprNode::AssignAddExpr).getRightOperand() = x and
+      x.getIntValue() = delta
+    )
+    or
     exists(ConstantIntegerExpr x |
       e2.(ExprNode::SubExpr).getLeftOperand() = e1 and
       e2.(ExprNode::SubExpr).getRightOperand() = x and
@@ -230,6 +238,11 @@ module ExprNode {
     override CS::AssignExpr e;
   }
 
+  /** A compound assignment operation. */
+  class AssignOperation extends Assignment, BinaryOperation {
+    override CS::AssignOperation e;
+  }
+
   /** A unary operation. */
   class UnaryOperation extends ExprNode {
     override CS::UnaryOperation e;
@@ -327,6 +340,12 @@ module ExprNode {
     override TAddOp getOp() { any() }
   }
 
+  class AssignAddExpr extends AssignOperation {
+    override CS::AssignAddExpr e;
+
+    override TAddOp getOp() { any() }
+  }
+
   /** A subtraction operation. */
   class SubExpr extends BinaryOperation {
     override CS::SubExpr e;
diff --git a/csharp/ql/lib/semmle/code/csharp/dispatch/Dispatch.qll b/csharp/ql/lib/semmle/code/csharp/dispatch/Dispatch.qll
index a83967441d74..f7f6c7a50be4 100644
--- a/csharp/ql/lib/semmle/code/csharp/dispatch/Dispatch.qll
+++ b/csharp/ql/lib/semmle/code/csharp/dispatch/Dispatch.qll
@@ -202,11 +202,9 @@ private module Internal {
   private predicate isPotentialEventCall(
     AssignArithmeticOperation aao, DynamicMemberAccess dma, string name
   ) {
-    exists(DynamicOperatorCall doc, AssignExpr ae |
-      ae = aao.getExpandedAssignment() and
-      dma = ae.getLValue() and
-      doc = ae.getRValue()
-    |
+    aao instanceof DynamicOperatorCall and
+    dma = aao.getLeftOperand() and
+    (
       aao instanceof AssignAddExpr and
       name = "add_" + dma.getLateBoundTargetName()
       or
diff --git a/csharp/ql/lib/semmle/code/csharp/exprs/Assignment.qll b/csharp/ql/lib/semmle/code/csharp/exprs/Assignment.qll
index 9fa2a93724d4..3cce72515d45 100644
--- a/csharp/ql/lib/semmle/code/csharp/exprs/Assignment.qll
+++ b/csharp/ql/lib/semmle/code/csharp/exprs/Assignment.qll
@@ -64,33 +64,31 @@ class AssignExpr extends Assignment, @simple_assign_expr {
 
 /**
  * An assignment operation. Either an arithmetic assignment operation
- * (`AssignArithmeticOperation`), a bitwise assignment operation
- * (`AssignBitwiseOperation`), or an event assignment (`AddOrRemoveEventExpr`).
+ * (`AssignArithmeticOperation`), a bitwise assignment operation or
+ * (`AssignBitwiseOperation`).
  */
-class AssignOperation extends Assignment, @assign_op_expr {
+class AssignOperation extends Assignment, OperatorCall, @assign_op_expr {
   override string getOperator() { none() }
 
   /**
-   * Gets the expanded version of this assignment operation, if any.
-   *
-   * For example, if this assignment operation is `x += y` then
-   * the expanded assignment is `x = x + y`.
-   *
-   * If an expanded version exists, then it is used in the control
-   * flow graph.
+   * Expanded versions of compound assignments are no longer extracted.
    */
-  AssignExpr getExpandedAssignment() { expr_parent(result, 2, this) }
+  deprecated AssignExpr getExpandedAssignment() { none() }
 
   /**
-   * Holds if this assignment operation has an expanded version.
-   *
-   * For example, if this assignment operation is `x += y` then
-   * it has the expanded version `x = x + y`.
-   *
-   * If an expanded version exists, then it is used in the control
-   * flow graph.
+   * Expanded versions of compound assignments are no longer extracted.
    */
-  predicate hasExpandedAssignment() { exists(this.getExpandedAssignment()) }
+  deprecated predicate hasExpandedAssignment() { none() }
+
+  override Expr getLeftOperand() { result = this.getChild(0) }
+
+  override Expr getRightOperand() { result = this.getChild(1) }
+
+  /** Gets the left operand of this assignment. */
+  override Expr getLValue() { result = this.getChild(0) }
+
+  /** Gets the right operand of this assignment. */
+  override Expr getRValue() { result = this.getChild(1) }
 
   override string toString() { result = "... " + this.getOperator() + " ..." }
 }
@@ -218,13 +216,21 @@ class AssignUnsighedRightShiftExpr extends AssignBitwiseOperation, @assign_urshi
  * An event assignment. Either an event addition (`AddEventExpr`) or an event
  * removal (`RemoveEventExpr`).
  */
-class AddOrRemoveEventExpr extends AssignOperation, @assign_event_expr {
+class AddOrRemoveEventExpr extends Assignment, @assign_event_expr {
+  override string getOperator() { none() }
+
   /** Gets the event targeted by this event assignment. */
   Event getTarget() { result = this.getLValue().getTarget() }
 
   override EventAccess getLValue() { result = this.getChild(1) }
 
   override Expr getRValue() { result = this.getChild(0) }
+
+  override EventAccess getLeftOperand() { result = this.getChild(1) }
+
+  override Expr getRightOperand() { result = this.getChild(0) }
+
+  override string toString() { result = "... " + this.getOperator() + " ..." }
 }
 
 /**
diff --git a/csharp/ql/lib/semmle/code/csharp/exprs/Call.qll b/csharp/ql/lib/semmle/code/csharp/exprs/Call.qll
index f8b51a990ed1..912cb23e06b7 100644
--- a/csharp/ql/lib/semmle/code/csharp/exprs/Call.qll
+++ b/csharp/ql/lib/semmle/code/csharp/exprs/Call.qll
@@ -493,12 +493,16 @@ class ConstructorInitializer extends Call, @constructor_init_expr {
  * }
  * ```
  */
-class OperatorCall extends Call, LateBindableExpr, @operator_invocation_expr {
+class OperatorCall extends Call, LateBindableExpr, @op_invoke_expr {
   override Operator getTarget() { expr_call(this, result) }
 
   override Operator getARuntimeTarget() { result = Call.super.getARuntimeTarget() }
 
-  override string toString() { result = "call to operator " + this.getTarget().getName() }
+  override string toString() {
+    if this instanceof DynamicOperatorCall
+    then result = "dynamic call to operator " + this.getLateBoundTargetName()
+    else result = "call to operator " + this.getTarget().getName()
+  }
 
   override string getAPrimaryQlClass() { result = "OperatorCall" }
 }
diff --git a/csharp/ql/lib/semmle/code/csharp/exprs/Dynamic.qll b/csharp/ql/lib/semmle/code/csharp/exprs/Dynamic.qll
index 04ea9f062a50..bfc5c36ff37c 100644
--- a/csharp/ql/lib/semmle/code/csharp/exprs/Dynamic.qll
+++ b/csharp/ql/lib/semmle/code/csharp/exprs/Dynamic.qll
@@ -96,13 +96,7 @@ class DynamicMethodCall extends DynamicExpr, MethodCall {
  * Unlike an ordinary call to a user-defined operator (`OperatorCall`), the
  * target operator may not be known at compile-time (as in the example above).
  */
-class DynamicOperatorCall extends DynamicExpr, OperatorCall {
-  override string toString() {
-    result = "dynamic call to operator " + this.getLateBoundTargetName()
-  }
-
-  override string getAPrimaryQlClass() { result = "DynamicOperatorCall" }
-}
+class DynamicOperatorCall extends DynamicExpr, OperatorCall { }
 
 /**
  * A call to a user-defined mutator operator where the operand is a `dynamic`
diff --git a/csharp/ql/lib/semmle/code/csharp/exprs/Expr.qll b/csharp/ql/lib/semmle/code/csharp/exprs/Expr.qll
index c3b9bcc363b3..7b5176278ce4 100644
--- a/csharp/ql/lib/semmle/code/csharp/exprs/Expr.qll
+++ b/csharp/ql/lib/semmle/code/csharp/exprs/Expr.qll
@@ -65,25 +65,11 @@ class Expr extends ControlFlowElement, @expr {
   /** Gets the enclosing callable of this expression, if any. */
   override Callable getEnclosingCallable() { enclosingCallable(this, result) }
 
-  pragma[nomagic]
-  private predicate isExpandedAssignmentRValueDescendant() {
-    this =
-      any(AssignOperation op).getExpandedAssignment().getRValue().getChildExpr(0).getAChildExpr()
-    or
-    exists(Expr parent |
-      parent.isExpandedAssignmentRValueDescendant() and
-      this = parent.getAChildExpr()
-    )
-  }
-
   /**
    * Holds if this expression is generated by the compiler and does not appear
    * explicitly in the source code.
    */
-  final predicate isImplicit() {
-    compiler_generated(this) or
-    this.isExpandedAssignmentRValueDescendant()
-  }
+  final predicate isImplicit() { compiler_generated(this) }
 
   /**
    * Gets an expression that is the result of stripping (recursively) all
diff --git a/csharp/ql/lib/semmlecode.csharp.dbscheme b/csharp/ql/lib/semmlecode.csharp.dbscheme
index e73ca2c93df8..eadfb04c00fc 100644
--- a/csharp/ql/lib/semmlecode.csharp.dbscheme
+++ b/csharp/ql/lib/semmlecode.csharp.dbscheme
@@ -1215,8 +1215,8 @@ case @expr.kind of
 @literal_expr = @bool_literal_expr | @char_literal_expr | @integer_literal_expr | @real_literal_expr
               | @string_literal_expr | @null_literal_expr;
 
-@assign_expr = @simple_assign_expr | @assign_op_expr | @local_var_decl_expr;
-@assign_op_expr =  @assign_arith_expr | @assign_bitwise_expr | @assign_event_expr | @assign_coalesce_expr;
+@assign_expr = @simple_assign_expr | @assign_op_expr | @local_var_decl_expr | @assign_event_expr;
+@assign_op_expr =  @assign_arith_expr | @assign_bitwise_expr | @assign_coalesce_expr;
 @assign_event_expr = @add_event_expr | @remove_event_expr;
 
 @assign_arith_expr = @assign_add_expr | @assign_sub_expr | @assign_mul_expr | @assign_div_expr
@@ -1270,14 +1270,15 @@ case @expr.kind of
 
 @anonymous_function_expr = @lambda_expr | @anonymous_method_expr;
 
-@call = @method_invocation_expr | @constructor_init_expr | @operator_invocation_expr
+@op_invoke_expr = @operator_invocation_expr | @assign_op_expr
+@call = @method_invocation_expr | @constructor_init_expr | @op_invoke_expr
       | @delegate_invocation_expr | @object_creation_expr | @call_access_expr
       | @local_function_invocation_expr | @function_pointer_invocation_expr;
 
 @call_access_expr = @property_access_expr | @event_access_expr | @indexer_access_expr;
 
 @late_bindable_expr = @dynamic_element_access_expr | @dynamic_member_access_expr
-                    | @object_creation_expr | @method_invocation_expr | @operator_invocation_expr;
+                    | @object_creation_expr | @method_invocation_expr | @op_invoke_expr;
 
 @throw_element = @throw_expr | @throw_stmt;
 
diff --git a/csharp/ql/src/Dead Code/DeadStoreOfLocal.ql b/csharp/ql/src/Dead Code/DeadStoreOfLocal.ql
index 0f6e6d11fb2c..59816a18b3fb 100644
--- a/csharp/ql/src/Dead Code/DeadStoreOfLocal.ql	
+++ b/csharp/ql/src/Dead Code/DeadStoreOfLocal.ql	
@@ -84,6 +84,8 @@ class RelevantDefinition extends AssignableDefinition {
       )
     or
     this instanceof AssignableDefinitions::PatternDefinition
+    or
+    this instanceof AssignableDefinitions::AssignOperationDefinition
   }
 
   /** Holds if this assignment may be live. */
diff --git a/csharp/ql/src/Likely Bugs/DangerousNonShortCircuitLogic.ql b/csharp/ql/src/Likely Bugs/DangerousNonShortCircuitLogic.ql
index b980bfba1aea..53bf2599a551 100644
--- a/csharp/ql/src/Likely Bugs/DangerousNonShortCircuitLogic.ql	
+++ b/csharp/ql/src/Likely Bugs/DangerousNonShortCircuitLogic.ql	
@@ -18,14 +18,9 @@ import csharp
 /** A use of `&` or `|` on operands of type boolean. */
 class NonShortCircuit extends BinaryBitwiseOperation {
   NonShortCircuit() {
-    (
-      this instanceof BitwiseAndExpr
-      or
-      this instanceof BitwiseOrExpr
-    ) and
-    not exists(AssignBitwiseOperation abo | abo.getExpandedAssignment().getRValue() = this) and
-    this.getLeftOperand().getType() instanceof BoolType and
-    this.getRightOperand().getType() instanceof BoolType
+    this instanceof BitwiseAndExpr
+    or
+    this instanceof BitwiseOrExpr
   }
 
   pragma[nomagic]
diff --git a/csharp/ql/src/Performance/StringConcatenationInLoop.ql b/csharp/ql/src/Performance/StringConcatenationInLoop.ql
index a015771610d5..3b3228588a4b 100644
--- a/csharp/ql/src/Performance/StringConcatenationInLoop.ql
+++ b/csharp/ql/src/Performance/StringConcatenationInLoop.ql
@@ -23,7 +23,6 @@ class StringCat extends AddExpr {
  * where `v` is a simple variable (and not, for example, a property).
  */
 predicate isSelfConcatAssignExpr(AssignExpr e, Variable v) {
-  not e = any(AssignAddExpr a).getExpandedAssignment() and
   exists(VariableAccess use |
     stringCatContains(e.getRValue(), use) and
     use.getTarget() = e.getTargetVariable() and
diff --git a/csharp/ql/src/Security Features/InsecureRandomness.ql b/csharp/ql/src/Security Features/InsecureRandomness.ql
index 2c2df7010c67..8237afdff130 100644
--- a/csharp/ql/src/Security Features/InsecureRandomness.ql	
+++ b/csharp/ql/src/Security Features/InsecureRandomness.ql	
@@ -89,11 +89,7 @@ module Random {
         e = any(SensitiveLibraryParameter v).getAnAssignedArgument()
         or
         // Assignment operation, e.g. += or similar
-        exists(AssignOperation ao |
-          ao.getRValue() = e and
-          // "expanded" assignments will be covered by simple assignment
-          not ao.hasExpandedAssignment()
-        |
+        exists(AssignOperation ao | ao.getRValue() = e |
           ao.getLValue() = any(SensitiveVariable v).getAnAccess() or
           ao.getLValue() = any(SensitiveProperty v).getAnAccess() or
           ao.getLValue() = any(SensitiveLibraryParameter v).getAnAccess()
diff --git a/csharp/ql/test/library-tests/assignments/AssignOperation.expected b/csharp/ql/test/library-tests/assignments/AssignOperation.expected
index f6f03fd050c6..0315bbe1c906 100644
--- a/csharp/ql/test/library-tests/assignments/AssignOperation.expected
+++ b/csharp/ql/test/library-tests/assignments/AssignOperation.expected
@@ -1,4 +1,3 @@
 | Assignments.cs:6:9:6:14 | ... += ... | Assignments.cs:6:9:6:9 | access to local variable x | Assignments.cs:6:14:6:14 | 1 |
 | Assignments.cs:9:9:9:14 | ... -= ... | Assignments.cs:9:9:9:9 | access to local variable d | Assignments.cs:9:14:9:14 | 2 |
 | Assignments.cs:12:9:12:17 | ... += ... | Assignments.cs:12:9:12:9 | access to local variable a | Assignments.cs:12:14:12:17 | this access |
-| Assignments.cs:14:9:14:35 | ... += ... | Assignments.cs:14:9:14:13 | access to event Event | Assignments.cs:14:18:14:35 | (...) => ... |
diff --git a/csharp/ql/test/library-tests/assignments/AssignOperationExpanded.expected b/csharp/ql/test/library-tests/assignments/AssignOperationExpanded.expected
deleted file mode 100644
index bcc9d11c42f5..000000000000
--- a/csharp/ql/test/library-tests/assignments/AssignOperationExpanded.expected
+++ /dev/null
@@ -1,3 +0,0 @@
-| Assignments.cs:6:9:6:14 | ... += ... | Assignments.cs:6:9:6:14 | ... = ... | Assignments.cs:6:9:6:9 | access to local variable x | Assignments.cs:6:9:6:14 | ... + ... | Assignments.cs:6:9:6:9 | access to local variable x | Assignments.cs:6:14:6:14 | 1 |
-| Assignments.cs:9:9:9:14 | ... -= ... | Assignments.cs:9:9:9:14 | ... = ... | Assignments.cs:9:9:9:9 | access to local variable d | Assignments.cs:9:9:9:14 | dynamic call to operator - | Assignments.cs:9:9:9:9 | access to local variable d | Assignments.cs:9:14:9:14 | 2 |
-| Assignments.cs:12:9:12:17 | ... += ... | Assignments.cs:12:9:12:17 | ... = ... | Assignments.cs:12:9:12:9 | access to local variable a | Assignments.cs:12:9:12:17 | call to operator + | Assignments.cs:12:9:12:9 | access to local variable a | Assignments.cs:12:14:12:17 | this access |
diff --git a/csharp/ql/test/library-tests/assignments/AssignOperationExpanded.ql b/csharp/ql/test/library-tests/assignments/AssignOperationExpanded.ql
deleted file mode 100644
index bd67776520fb..000000000000
--- a/csharp/ql/test/library-tests/assignments/AssignOperationExpanded.ql
+++ /dev/null
@@ -1,22 +0,0 @@
-import csharp
-
-predicate getExpandedOperatorArgs(Expr e, Expr left, Expr right) {
-  e =
-    any(BinaryArithmeticOperation bo |
-      bo.getLeftOperand() = left and
-      bo.getRightOperand() = right
-    )
-  or
-  e =
-    any(OperatorCall oc |
-      oc.getArgument(0) = left and
-      oc.getArgument(1) = right
-    )
-}
-
-from AssignOperation ao, AssignExpr ae, Expr op, Expr left, Expr right
-where
-  ae = ao.getExpandedAssignment() and
-  op = ae.getRValue() and
-  getExpandedOperatorArgs(op, left, right)
-select ao, ae, ae.getLValue(), op, left, right
diff --git a/csharp/ql/test/library-tests/csharp11/operators.expected b/csharp/ql/test/library-tests/csharp11/operators.expected
index 2c7bda6800d2..6bce5dfa6f5e 100644
--- a/csharp/ql/test/library-tests/csharp11/operators.expected
+++ b/csharp/ql/test/library-tests/csharp11/operators.expected
@@ -1,7 +1,6 @@
 binarybitwise
 | Operators.cs:7:18:7:25 | ... >>> ... | Operators.cs:7:18:7:19 | access to local variable x1 | Operators.cs:7:25:7:25 | 2 | >>> | UnsignedRightShiftExpr |
 | Operators.cs:10:18:10:25 | ... >>> ... | Operators.cs:10:18:10:19 | access to local variable y1 | Operators.cs:10:25:10:25 | 3 | >>> | UnsignedRightShiftExpr |
-| Operators.cs:13:9:13:16 | ... >>> ... | Operators.cs:13:9:13:9 | access to local variable z | Operators.cs:13:16:13:16 | 5 | >>> | UnsignedRightShiftExpr |
 assignbitwise
 | Operators.cs:13:9:13:16 | ... >>>= ... | Operators.cs:13:9:13:9 | access to local variable z | Operators.cs:13:16:13:16 | 5 | >>>= | AssignUnsighedRightShiftExpr |
 userdefined
diff --git a/csharp/ql/test/library-tests/csharp8/NullCoalescingAssignment.expected b/csharp/ql/test/library-tests/csharp8/NullCoalescingAssignment.expected
index d388d2fdb7c2..1b4f30ad6e75 100644
--- a/csharp/ql/test/library-tests/csharp8/NullCoalescingAssignment.expected
+++ b/csharp/ql/test/library-tests/csharp8/NullCoalescingAssignment.expected
@@ -1,5 +1,4 @@
 nullcoalescing
-| NullCoalescingAssignment.cs:8:9:8:18 | ... ?? ... |
 | NullableRefTypes.cs:94:17:94:25 | ... ?? ... |
 assignments
-| NullCoalescingAssignment.cs:8:9:8:18 | ... ??= ... | NullCoalescingAssignment.cs:8:9:8:18 | ... = ... |
+| NullCoalescingAssignment.cs:8:9:8:18 | ... ??= ... |
diff --git a/csharp/ql/test/library-tests/csharp8/NullCoalescingAssignment.ql b/csharp/ql/test/library-tests/csharp8/NullCoalescingAssignment.ql
index a3a8ca20e927..1a452274677c 100644
--- a/csharp/ql/test/library-tests/csharp8/NullCoalescingAssignment.ql
+++ b/csharp/ql/test/library-tests/csharp8/NullCoalescingAssignment.ql
@@ -2,6 +2,4 @@ import csharp
 
 query predicate nullcoalescing(NullCoalescingExpr expr) { any() }
 
-query predicate assignments(AssignCoalesceExpr expr, Expr expanded) {
-  expanded = expr.getExpandedAssignment()
-}
+query predicate assignments(AssignCoalesceExpr expr) { any() }
diff --git a/csharp/ql/test/library-tests/csharp8/NullCoalescingControlFlow.expected b/csharp/ql/test/library-tests/csharp8/NullCoalescingControlFlow.expected
index 2657c450d681..463002be5414 100644
--- a/csharp/ql/test/library-tests/csharp8/NullCoalescingControlFlow.expected
+++ b/csharp/ql/test/library-tests/csharp8/NullCoalescingControlFlow.expected
@@ -4,9 +4,7 @@
 | NullCoalescingAssignment.cs:7:9:7:24 | ... ...; | NullCoalescingAssignment.cs:7:20:7:23 | null | semmle.label | successor |
 | NullCoalescingAssignment.cs:7:16:7:23 | Object o = ... | NullCoalescingAssignment.cs:8:9:8:19 | ...; | semmle.label | successor |
 | NullCoalescingAssignment.cs:7:20:7:23 | null | NullCoalescingAssignment.cs:7:16:7:23 | Object o = ... | semmle.label | successor |
-| NullCoalescingAssignment.cs:8:9:8:9 | access to local variable o | NullCoalescingAssignment.cs:8:9:8:18 | ... ?? ... | semmle.label | non-null |
-| NullCoalescingAssignment.cs:8:9:8:9 | access to local variable o | NullCoalescingAssignment.cs:8:15:8:18 | this access | semmle.label | null |
-| NullCoalescingAssignment.cs:8:9:8:18 | ... = ... | NullCoalescingAssignment.cs:5:10:5:23 | exit NullCoalescing (normal) | semmle.label | successor |
-| NullCoalescingAssignment.cs:8:9:8:18 | ... ?? ... | NullCoalescingAssignment.cs:8:9:8:18 | ... = ... | semmle.label | successor |
+| NullCoalescingAssignment.cs:8:9:8:9 | access to local variable o | NullCoalescingAssignment.cs:8:15:8:18 | this access | semmle.label | successor |
+| NullCoalescingAssignment.cs:8:9:8:18 | ... ??= ... | NullCoalescingAssignment.cs:5:10:5:23 | exit NullCoalescing (normal) | semmle.label | successor |
 | NullCoalescingAssignment.cs:8:9:8:19 | ...; | NullCoalescingAssignment.cs:8:9:8:9 | access to local variable o | semmle.label | successor |
-| NullCoalescingAssignment.cs:8:15:8:18 | this access | NullCoalescingAssignment.cs:8:9:8:18 | ... ?? ... | semmle.label | successor |
+| NullCoalescingAssignment.cs:8:15:8:18 | this access | NullCoalescingAssignment.cs:8:9:8:18 | ... ??= ... | semmle.label | successor |
diff --git a/csharp/ql/test/library-tests/dataflow/local/DataFlowStep.expected b/csharp/ql/test/library-tests/dataflow/local/DataFlowStep.expected
index 861e4c519a82..29533a67083f 100644
--- a/csharp/ql/test/library-tests/dataflow/local/DataFlowStep.expected
+++ b/csharp/ql/test/library-tests/dataflow/local/DataFlowStep.expected
@@ -32,13 +32,14 @@
 | LocalDataFlow.cs:59:13:59:25 | SSA def(sink1) | LocalDataFlow.cs:60:9:60:13 | access to local variable sink1 |
 | LocalDataFlow.cs:59:21:59:25 | "abc" | LocalDataFlow.cs:59:13:59:17 | access to local variable sink1 |
 | LocalDataFlow.cs:60:9:60:13 | access to local variable sink1 | LocalDataFlow.cs:60:9:60:22 | SSA def(sink1) |
-| LocalDataFlow.cs:60:9:60:22 | ... + ... | LocalDataFlow.cs:60:9:60:13 | access to local variable sink1 |
+| LocalDataFlow.cs:60:9:60:22 | ... += ... | LocalDataFlow.cs:60:9:60:13 | access to local variable sink1 |
 | LocalDataFlow.cs:60:9:60:22 | SSA def(sink1) | LocalDataFlow.cs:61:15:61:19 | access to local variable sink1 |
+| LocalDataFlow.cs:60:18:60:22 | [post] access to local variable sink0 | LocalDataFlow.cs:168:20:168:24 | access to local variable sink0 |
 | LocalDataFlow.cs:60:18:60:22 | access to local variable sink0 | LocalDataFlow.cs:168:20:168:24 | access to local variable sink0 |
 | LocalDataFlow.cs:61:15:61:19 | [post] access to local variable sink1 | LocalDataFlow.cs:68:21:68:25 | access to local variable sink1 |
 | LocalDataFlow.cs:61:15:61:19 | access to local variable sink1 | LocalDataFlow.cs:68:21:68:25 | access to local variable sink1 |
 | LocalDataFlow.cs:64:9:64:16 | access to local variable nonSink0 | LocalDataFlow.cs:64:9:64:25 | SSA def(nonSink0) |
-| LocalDataFlow.cs:64:9:64:25 | ... + ... | LocalDataFlow.cs:64:9:64:16 | access to local variable nonSink0 |
+| LocalDataFlow.cs:64:9:64:25 | ... += ... | LocalDataFlow.cs:64:9:64:16 | access to local variable nonSink0 |
 | LocalDataFlow.cs:64:9:64:25 | SSA def(nonSink0) | LocalDataFlow.cs:65:15:65:22 | access to local variable nonSink0 |
 | LocalDataFlow.cs:65:15:65:22 | [post] access to local variable nonSink0 | LocalDataFlow.cs:72:20:72:27 | access to local variable nonSink0 |
 | LocalDataFlow.cs:65:15:65:22 | access to local variable nonSink0 | LocalDataFlow.cs:72:20:72:27 | access to local variable nonSink0 |
diff --git a/csharp/ql/test/library-tests/dataflow/local/TaintTrackingStep.expected b/csharp/ql/test/library-tests/dataflow/local/TaintTrackingStep.expected
index 0950638d8306..4be5dcf12952 100644
--- a/csharp/ql/test/library-tests/dataflow/local/TaintTrackingStep.expected
+++ b/csharp/ql/test/library-tests/dataflow/local/TaintTrackingStep.expected
@@ -31,19 +31,20 @@
 | LocalDataFlow.cs:59:13:59:17 | access to local variable sink1 | LocalDataFlow.cs:59:13:59:25 | SSA def(sink1) |
 | LocalDataFlow.cs:59:13:59:25 | SSA def(sink1) | LocalDataFlow.cs:60:9:60:13 | access to local variable sink1 |
 | LocalDataFlow.cs:59:21:59:25 | "abc" | LocalDataFlow.cs:59:13:59:17 | access to local variable sink1 |
-| LocalDataFlow.cs:60:9:60:13 | access to local variable sink1 | LocalDataFlow.cs:60:9:60:22 | ... + ... |
+| LocalDataFlow.cs:60:9:60:13 | access to local variable sink1 | LocalDataFlow.cs:60:9:60:22 | ... += ... |
 | LocalDataFlow.cs:60:9:60:13 | access to local variable sink1 | LocalDataFlow.cs:60:9:60:22 | SSA def(sink1) |
-| LocalDataFlow.cs:60:9:60:22 | ... + ... | LocalDataFlow.cs:60:9:60:13 | access to local variable sink1 |
+| LocalDataFlow.cs:60:9:60:22 | ... += ... | LocalDataFlow.cs:60:9:60:13 | access to local variable sink1 |
 | LocalDataFlow.cs:60:9:60:22 | SSA def(sink1) | LocalDataFlow.cs:61:15:61:19 | access to local variable sink1 |
-| LocalDataFlow.cs:60:18:60:22 | access to local variable sink0 | LocalDataFlow.cs:60:9:60:22 | ... + ... |
+| LocalDataFlow.cs:60:18:60:22 | [post] access to local variable sink0 | LocalDataFlow.cs:168:20:168:24 | access to local variable sink0 |
+| LocalDataFlow.cs:60:18:60:22 | access to local variable sink0 | LocalDataFlow.cs:60:9:60:22 | ... += ... |
 | LocalDataFlow.cs:60:18:60:22 | access to local variable sink0 | LocalDataFlow.cs:168:20:168:24 | access to local variable sink0 |
 | LocalDataFlow.cs:61:15:61:19 | [post] access to local variable sink1 | LocalDataFlow.cs:68:21:68:25 | access to local variable sink1 |
 | LocalDataFlow.cs:61:15:61:19 | access to local variable sink1 | LocalDataFlow.cs:68:21:68:25 | access to local variable sink1 |
-| LocalDataFlow.cs:64:9:64:16 | access to local variable nonSink0 | LocalDataFlow.cs:64:9:64:25 | ... + ... |
+| LocalDataFlow.cs:64:9:64:16 | access to local variable nonSink0 | LocalDataFlow.cs:64:9:64:25 | ... += ... |
 | LocalDataFlow.cs:64:9:64:16 | access to local variable nonSink0 | LocalDataFlow.cs:64:9:64:25 | SSA def(nonSink0) |
-| LocalDataFlow.cs:64:9:64:25 | ... + ... | LocalDataFlow.cs:64:9:64:16 | access to local variable nonSink0 |
+| LocalDataFlow.cs:64:9:64:25 | ... += ... | LocalDataFlow.cs:64:9:64:16 | access to local variable nonSink0 |
 | LocalDataFlow.cs:64:9:64:25 | SSA def(nonSink0) | LocalDataFlow.cs:65:15:65:22 | access to local variable nonSink0 |
-| LocalDataFlow.cs:64:21:64:25 | "abc" | LocalDataFlow.cs:64:9:64:25 | ... + ... |
+| LocalDataFlow.cs:64:21:64:25 | "abc" | LocalDataFlow.cs:64:9:64:25 | ... += ... |
 | LocalDataFlow.cs:65:15:65:22 | [post] access to local variable nonSink0 | LocalDataFlow.cs:72:20:72:27 | access to local variable nonSink0 |
 | LocalDataFlow.cs:65:15:65:22 | access to local variable nonSink0 | LocalDataFlow.cs:72:20:72:27 | access to local variable nonSink0 |
 | LocalDataFlow.cs:68:13:68:17 | access to local variable sink5 | LocalDataFlow.cs:68:13:68:32 | SSA def(sink5) |
diff --git a/csharp/ql/test/library-tests/dynamic/DynamicOperatorCall.expected b/csharp/ql/test/library-tests/dynamic/DynamicOperatorCall.expected
index 6c0a054c84ab..6e98bffaf6f8 100644
--- a/csharp/ql/test/library-tests/dynamic/DynamicOperatorCall.expected
+++ b/csharp/ql/test/library-tests/dynamic/DynamicOperatorCall.expected
@@ -1,6 +1,6 @@
 | dynamic.cs:35:13:35:14 | dynamic call to operator - | - | 0 | dynamic.cs:35:14:35:14 | access to local variable d |
 | dynamic.cs:36:13:36:17 | dynamic call to operator + | + | 0 | dynamic.cs:36:13:36:13 | access to local variable d |
 | dynamic.cs:36:13:36:17 | dynamic call to operator + | + | 1 | dynamic.cs:36:17:36:17 | access to local variable d |
-| dynamic.cs:37:9:37:14 | dynamic call to operator + | + | 0 | dynamic.cs:37:9:37:9 | access to local variable d |
-| dynamic.cs:37:9:37:14 | dynamic call to operator + | + | 1 | dynamic.cs:37:14:37:14 | access to local variable d |
+| dynamic.cs:37:9:37:14 | ... += ... | + | 0 | dynamic.cs:37:9:37:9 | access to local variable d |
+| dynamic.cs:37:9:37:14 | ... += ... | + | 1 | dynamic.cs:37:14:37:14 | access to local variable d |
 | dynamic.cs:47:9:47:11 | dynamic call to operator ++ | ++ | 0 | dynamic.cs:47:9:47:9 | access to local variable d |
diff --git a/csharp/ql/test/library-tests/dynamic/PrintAst.expected b/csharp/ql/test/library-tests/dynamic/PrintAst.expected
index 3bde4d42d862..3526e0b6bf54 100644
--- a/csharp/ql/test/library-tests/dynamic/PrintAst.expected
+++ b/csharp/ql/test/library-tests/dynamic/PrintAst.expected
@@ -105,12 +105,12 @@ dynamic.cs:
 #   35|       15: [ExprStmt] ...;
 #   35|         0: [AssignExpr] ... = ...
 #   35|           0: [LocalVariableAccess] access to local variable d
-#   35|           1: [DynamicOperatorCall] dynamic call to operator -
+#   35|           1: [OperatorCall] dynamic call to operator -
 #   35|             0: [LocalVariableAccess] access to local variable d
 #   36|       16: [ExprStmt] ...;
 #   36|         0: [AssignExpr] ... = ...
 #   36|           0: [LocalVariableAccess] access to local variable d
-#   36|           1: [DynamicOperatorCall] dynamic call to operator +
+#   36|           1: [OperatorCall] dynamic call to operator +
 #   36|             0: [LocalVariableAccess] access to local variable d
 #   36|             1: [LocalVariableAccess] access to local variable d
 #   37|       17: [ExprStmt] ...;
@@ -141,7 +141,7 @@ dynamic.cs:
 #   44|         0: [PostIncrExpr] ...++
 #   44|           0: [LocalVariableAccess] access to local variable i
 #   47|       23: [ExprStmt] ...;
-#   47|         0: [DynamicOperatorCall] dynamic call to operator ++
+#   47|         0: [OperatorCall] dynamic call to operator ++
 #   47|           0: [LocalVariableAccess] access to local variable d
 #   50|       24: [ExprStmt] ...;
 #   50|         0: [PostIncrExpr] ...++
diff --git a/csharp/ql/test/query-tests/Dead Code/DeadStoreOfLocal/DeadStoreOfLocal.expected b/csharp/ql/test/query-tests/Dead Code/DeadStoreOfLocal/DeadStoreOfLocal.expected
index 6271d6276c72..2073fce06a77 100644
--- a/csharp/ql/test/query-tests/Dead Code/DeadStoreOfLocal/DeadStoreOfLocal.expected	
+++ b/csharp/ql/test/query-tests/Dead Code/DeadStoreOfLocal/DeadStoreOfLocal.expected	
@@ -1,7 +1,7 @@
 | DeadStoreOfLocal.cs:12:13:12:20 | Int32 x = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:12:13:12:13 | x | x |
 | DeadStoreOfLocal.cs:19:21:19:25 | ... = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:18:13:18:13 | x | x |
 | DeadStoreOfLocal.cs:44:13:44:20 | Int32 x = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:44:13:44:13 | x | x |
-| DeadStoreOfLocal.cs:50:9:50:14 | ... = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:49:13:49:13 | x | x |
+| DeadStoreOfLocal.cs:50:9:50:14 | ... += ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:49:13:49:13 | x | x |
 | DeadStoreOfLocal.cs:56:9:56:11 | ...++ | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:55:13:55:13 | x | x |
 | DeadStoreOfLocal.cs:82:22:82:24 | String val | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:82:22:82:24 | val | val |
 | DeadStoreOfLocal.cs:101:13:101:37 | ... = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:94:40:94:44 | extra | extra |
diff --git a/csharp/ql/test/query-tests/Security Features/CWE-112/MissingXMLValidation.expected b/csharp/ql/test/query-tests/Security Features/CWE-112/MissingXMLValidation.expected
index 2477cd600e0f..fc8933cac930 100644
--- a/csharp/ql/test/query-tests/Security Features/CWE-112/MissingXMLValidation.expected	
+++ b/csharp/ql/test/query-tests/Security Features/CWE-112/MissingXMLValidation.expected	
@@ -3,7 +3,6 @@
 | MissingXMLValidation.cs:21:26:21:58 | object creation of type StringReader | MissingXMLValidation.cs:12:34:12:56 | access to property QueryString : NameValueCollection | MissingXMLValidation.cs:21:26:21:58 | object creation of type StringReader | This XML processing depends on a $@ without validation because the 'XmlReaderSettings' instance does not specify the 'ValidationType' as 'Schema'. | MissingXMLValidation.cs:12:34:12:56 | access to property QueryString | user-provided value |
 | MissingXMLValidation.cs:27:26:27:58 | object creation of type StringReader | MissingXMLValidation.cs:12:34:12:56 | access to property QueryString : NameValueCollection | MissingXMLValidation.cs:27:26:27:58 | object creation of type StringReader | This XML processing depends on a $@ without validation because the 'XmlReaderSettings' instance does not specify the 'ValidationType' as 'Schema'. | MissingXMLValidation.cs:12:34:12:56 | access to property QueryString | user-provided value |
 | MissingXMLValidation.cs:45:26:45:58 | object creation of type StringReader | MissingXMLValidation.cs:12:34:12:56 | access to property QueryString : NameValueCollection | MissingXMLValidation.cs:45:26:45:58 | object creation of type StringReader | This XML processing depends on a $@ without validation because the 'XmlReaderSettings' instance specifies 'ProcessInlineSchema'. | MissingXMLValidation.cs:12:34:12:56 | access to property QueryString | user-provided value |
-| MissingXMLValidation.cs:45:26:45:58 | object creation of type StringReader | MissingXMLValidation.cs:12:34:12:56 | access to property QueryString : NameValueCollection | MissingXMLValidation.cs:45:26:45:58 | object creation of type StringReader | This XML processing depends on a $@ without validation because the 'XmlReaderSettings' instance specifies 'ProcessSchemaLocation'. | MissingXMLValidation.cs:12:34:12:56 | access to property QueryString | user-provided value |
 edges
 | MissingXMLValidation.cs:12:16:12:30 | access to local variable userProvidedXml : String | MissingXMLValidation.cs:16:43:16:57 | access to local variable userProvidedXml : String | provenance |  |
 | MissingXMLValidation.cs:12:16:12:30 | access to local variable userProvidedXml : String | MissingXMLValidation.cs:21:43:21:57 | access to local variable userProvidedXml : String | provenance |  |