Taint branches of tainted ternary expressions (#6393)

CHANGELOG.md

@@ -19,7 +19,10 @@
 
 ### Bug Fixes
 
-* None.
+* Treat closures in the branches of ternary expressions as escaping
+  when the whole expression is escaping in the `unneeded_escaping` rule.  
+  [SimplyDanny](https://github.com/SimplyDanny)
+  [#6386](https://github.com/realm/SwiftLint/pull/6386)
 
 ## 0.63.0-rc.2: High-Speed Extraction
 

Source/SwiftLintBuiltInRules/Rules/Lint/UnneededEscapingRule.swift

@@ -102,6 +102,11 @@ struct UnneededEscapingRule: Rule {
                 var cs = [1: c]
             }
             """, excludeFromDocumentation: true),
+            Example("""
+            func f(c: @escaping () -> Void) {
+                f(true ? c : { })
+            }
+            """),
         ],
         triggeringExamples: [
             Example("""
@@ -324,6 +329,9 @@ private final class EscapeChecker: SyntaxVisitor {
            let declRef = optChain.expression.as(DeclReferenceExprSyntax.self) {
             return taintedVariables.contains(declRef.baseName.text)
         }
+        if let ternary = expr.as(TernaryExprSyntax.self) {
+            return isTainted(ternary.thenExpression) || isTainted(ternary.elseExpression)
+        }
         return false
     }
 }