Ignore the second operands of binary left shift operations

CHANGELOG.md

@@ -104,6 +104,11 @@
   [Marcelo Fabri](https://github.com/marcelofabri)
   [#5172](https://github.com/realm/SwiftLint/issues/5172)
 
+* The `no_magic_numbers` rule will not trigger for bitwise shift
+  operations.  
+  [Martin Redington](https://github.com/mildm8nnered)
+  [#5171](https://github.com/realm/SwiftLint/issues/5171)
+
 ## 0.52.4: Lid Switch
 
 #### Breaking

Source/SwiftLintBuiltInRules/Rules/Idiomatic/NoMagicNumbersRule.swift

@@ -68,7 +68,11 @@ struct NoMagicNumbersRule: SwiftSyntaxRule, OptInRule, ConfigurationProviderRule
                 let a = Int(3)
             }
             class MyTest: XCTestCase {}
-            """)
+            """),
+            Example("let foo = 1 << 2"),
+            Example("let foo = 1 >> 2"),
+            Example("let foo = 2 >> 2"),
+            Example("let foo = 2 << 2")
         ],
         triggeringExamples: [
             Example("foo(↓321)"),
@@ -131,6 +135,9 @@ private extension NoMagicNumbersRule {
             if node.isMemberOfATestClass(testParentClasses) {
                 return
             }
+            if node.isOperandOfBitwiseShiftOperation() {
+                return
+            }
             let violation = node.positionAfterSkippingLeadingTrivia
             if let extendedTypeName = node.extendedTypeName() {
                 if !testClasses.contains(extendedTypeName) {
@@ -196,4 +203,20 @@ private extension ExprSyntaxProtocol {
         }
         return nil
     }
+
+    func isOperandOfBitwiseShiftOperation() -> Bool {
+        guard
+            let siblings = parent?.as(ExprListSyntax.self)?.children(viewMode: .sourceAccurate),
+            siblings.count == 3
+        else {
+            return false
+        }
+
+        let operatorIndex = siblings.index(after: siblings.startIndex)
+        if let tokenKind = siblings[operatorIndex].as(BinaryOperatorExprSyntax.self)?.operatorToken.tokenKind {
+            return tokenKind == .binaryOperator("<<") || tokenKind == .binaryOperator(">>")
+        }
+
+        return false
+    }
 }