Merge pull request #21417 from aschackmull/csharp/binary-assignment

C#: Make Assignment extend BinaryOperation.

csharp/downgrades/e73ca2c93df8aae162f1704edc4817a5cb330529/upgrade.properties

@@ -0,0 +1,2 @@
+description: Remove inclusion of @assign_expr in @bin_op
+compatibility: full

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

@@ -11,7 +11,7 @@ import Expr
  * (`LocalVariableDeclAndInitExpr`), a simple assignment (`AssignExpr`), or
  * an assignment operation (`AssignOperation`).
  */
-class Assignment extends Operation, @assign_expr {
+class Assignment extends BinaryOperation, @assign_expr {
   Assignment() {
     this instanceof LocalVariableDeclExpr
     implies
@@ -20,6 +20,10 @@ class Assignment extends Operation, @assign_expr {
     expr_parent(_, 0, this)
   }
 
+  override Expr getLeftOperand() { result = this.getChild(1) }
+
+  override Expr getRightOperand() { result = this.getChild(0) }
+
   /** Gets the left operand of this assignment. */
   Expr getLValue() { result = this.getChild(1) }
 

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

@@ -244,7 +244,8 @@ class UnaryOperation extends Operation, @un_op {
  * A binary operation. Either a binary arithmetic operation
  * (`BinaryArithmeticOperation`), a binary bitwise operation
  * (`BinaryBitwiseOperation`), a comparison operation (`ComparisonOperation`),
- * or a binary logical operation (`BinaryLogicalOperation`).
+ * a binary logical operation (`BinaryLogicalOperation`), or an
+ * assignment (`Assignment`).
  */
 class BinaryOperation extends Operation, @bin_op {
   /** Gets the left operand of this binary operation. */

csharp/ql/lib/semmlecode.csharp.dbscheme

@@ -1261,10 +1261,10 @@ case @expr.kind of
 @rel_op_expr = @gt_expr | @lt_expr| @ge_expr | @le_expr;
 @comp_expr = @equality_op_expr | @rel_op_expr;
 
-@op_expr = @assign_expr | @un_op | @bin_op | @ternary_op;
+@op_expr = @un_op | @bin_op | @ternary_op;
 
 @ternary_op = @ternary_log_op_expr;
-@bin_op = @bin_arith_op_expr | @bin_log_op_expr | @bin_bit_op_expr | @comp_expr;
+@bin_op = @assign_expr | @bin_arith_op_expr | @bin_log_op_expr | @bin_bit_op_expr | @comp_expr;
 @un_op = @un_arith_op_expr | @un_log_op_expr | @un_bit_op_expr | @sizeof_expr
        | @pointer_indirection_expr | @address_of_expr;
 

csharp/ql/lib/upgrades/178a7e6cf335486d33d4e49543148e3f57f04a9a/upgrade.properties

@@ -0,0 +1,2 @@
+description: Expand @bin_op union to include @assign_expr
+compatibility: full

csharp/ql/test/library-tests/linq/Linq2.ql

@@ -5,4 +5,5 @@
 import csharp
 
 from BinaryOperation e
+where not e instanceof Assignment
 select e, e.getAnOperand()