Legacy Constant

ID

swift.legacy_constant

Severity

info

Remediation Complexity

medium

Remediation Risk

low

Remediation Effort

medium

Resource

Code Smell

Language

Swift

Tags

code-smell, modernisation

Description

Reports references to legacy C-style global constants imported from Foundation / CoreGraphics that have struct-scoped Swift equivalents.

M_PI                       // FLAW — use Double.pi
CGFLOAT_MIN                // FLAW — use CGFloat.leastNormalMagnitude
CGFLOAT_MAX                // FLAW — use CGFloat.greatestFiniteMagnitude
DBL_MAX                    // FLAW — use Double.greatestFiniteMagnitude

Double.pi                  // OK
CGFloat.leastNormalMagnitude   // OK

Rationale

The Swift constants are:

  • Type-scoped — autocompletion works, the type is unambiguous.

  • Documented in Swift API reference, not buried in C headers.

  • Consistent across platforms.

The legacy macros only exist because the Foundation / CoreGraphics modules expose the C symbols for ObjC compatibility.

Remediation

let pi = Double.pi
let halfPi = Double.pi / 2
let minF = CGFloat.leastNormalMagnitude
let maxF = CGFloat.greatestFiniteMagnitude
let minD = Double.leastNormalMagnitude
let maxD = Double.greatestFiniteMagnitude

References