AST: add SetterMethodCall as instance of LhsExpr

ql/src/codeql_ruby/ast/Call.qll

@@ -7,6 +7,8 @@ private import internal.Call
 class Call extends Expr {
   override Call::Range range;
 
+  Call() { range.isNormal() }
+
   override string getAPrimaryQlClass() { result = "Call" }
 
   /**
@@ -93,6 +95,19 @@ class MethodCall extends Call {
   final Block getBlock() { result = range.getBlock() }
 }
 
+/**
+ * A call to a setter method.
+ * ```rb
+ * self.foo = 10
+ * a[0] = 10
+ * ```
+ */
+class SetterMethodCall extends LhsExpr {
+  final override SetterMethodCall::Range range;
+
+  final override string getAPrimaryQlClass() { result = "SetterMethodCall" }
+}
+
 /**
  * An element reference; a call to the `[]` method.
  * ```rb

ql/src/codeql_ruby/ast/internal/Call.qll

@@ -1,6 +1,7 @@
 private import codeql_ruby.AST
 private import codeql_ruby.ast.internal.AST
 private import codeql_ruby.ast.internal.Expr
+private import codeql_ruby.ast.internal.Pattern
 private import codeql_ruby.ast.internal.TreeSitter
 private import codeql_ruby.ast.internal.Variable
 
@@ -8,6 +9,12 @@ module Call {
   abstract class Range extends Expr::Range {
     abstract Expr getArgument(int n);
 
+    final predicate isSetter() { this instanceof LhsExpr }
+
+    final predicate isNormal() {
+      not isSetter() or generated.getParent() instanceof AssignOperation
+    }
+
     override predicate child(string label, AstNode::Range child) {
       label = "getArgument" and child = getArgument(_)
     }
@@ -111,6 +118,30 @@ module ElementReference {
   }
 }
 
+module SetterMethodCall {
+  class Range extends LhsExpr::Range {
+    private MethodCall::Range range;
+
+    Range() { this = range }
+
+    final Expr getReceiver() { result = range.getReceiver() }
+
+    final Expr getArgument(int n) { result = range.getArgument(n) }
+
+    final string getMethodName() { result = range.getMethodName() }
+
+    final override string toString() { result = range.toString() }
+
+    final override predicate child(string label, AstNode::Range child) {
+      super.child(label, child)
+      or
+      label = "getReceiver" and child = getReceiver()
+      or
+      label = "getArgument" and child = getArgument(_)
+    }
+  }
+}
+
 module YieldCall {
   class Range extends Call::Range, @yield {
     final override Generated::Yield generated;

ql/test/library-tests/ast/calls/calls.expected

@@ -77,6 +77,9 @@ callsWithNoReceiverArgumentsOrBlock
 | calls.rb:305:5:305:9 | call to super | super |
 | calls.rb:310:1:310:3 | call to foo | foo |
 | calls.rb:311:1:311:3 | call to foo | foo |
+| calls.rb:315:1:315:3 | call to foo | foo |
+| calls.rb:316:22:316:24 | call to foo | foo |
+| calls.rb:317:5:317:7 | call to foo | foo |
 callsWithArguments
 | calls.rb:14:1:14:11 | call to foo | foo | 0 | calls.rb:14:5:14:5 | 0 |
 | calls.rb:14:1:14:11 | call to foo | foo | 1 | calls.rb:14:8:14:8 | 1 |
@@ -184,6 +187,7 @@ callsWithReceiver
 | calls.rb:305:5:305:15 | call to super | calls.rb:305:5:305:9 | call to super |
 | calls.rb:310:1:310:6 | call to call | calls.rb:310:1:310:3 | call to foo |
 | calls.rb:311:1:311:7 | call to call | calls.rb:311:1:311:3 | call to foo |
+| calls.rb:318:1:318:10 | call to count | calls.rb:318:1:318:4 | self |
 callsWithBlock
 | calls.rb:17:1:17:17 | call to foo | calls.rb:17:5:17:17 | { ... } |
 | calls.rb:20:1:22:3 | call to foo | calls.rb:20:5:22:3 | do ... end |
@@ -221,3 +225,11 @@ superCallsWithBlock
 | calls.rb:291:5:291:26 | call to super | calls.rb:291:11:291:26 | do ... end |
 | calls.rb:292:5:292:30 | call to super | calls.rb:292:16:292:30 | { ... } |
 | calls.rb:293:5:293:33 | call to super | calls.rb:293:16:293:33 | do ... end |
+setterCalls
+| calls.rb:314:1:314:8 | call to foo |
+| calls.rb:315:1:315:6 | ...[...] |
+| calls.rb:316:1:316:8 | call to foo |
+| calls.rb:316:12:316:19 | call to bar |
+| calls.rb:316:22:316:27 | ...[...] |
+| calls.rb:317:5:317:10 | ...[...] |
+| calls.rb:318:1:318:10 | call to count |

ql/test/library-tests/ast/calls/calls.ql

@@ -30,3 +30,5 @@ query predicate superCalls(SuperCall c) { any() }
 query predicate superCallsWithArguments(SuperCall c, int n, Expr argN) { argN = c.getArgument(n) }
 
 query predicate superCallsWithBlock(SuperCall c, Block b) { b = c.getBlock() }
+
+query predicate setterCalls(SetterMethodCall c) { any() }

ql/test/library-tests/ast/calls/calls.rb

@@ -310,3 +310,9 @@ end
 foo.()
 foo.(1)
 
+# setter calls
+self.foo = 10
+foo[0] = 10
+self.foo, *self.bar, foo[4] = [1, 2, 3, 4]
+a, *foo[5] = [1, 2, 3]
+self.count += 1