SwiftUI: Prefer scaledToFit()/scaledToFill() over aspectRatio(contentMode:)

Source/SwiftLintBuiltInRules/Models/BuiltInRules.swift

@@ -150,6 +150,7 @@ public let builtInRules: [any Rule.Type] = [
     PeriodSpacingRule.self,
     PreferKeyPathRule.self,
     PreferNimbleRule.self,
+    PreferScaledToFitAndScaledToFill.self,
     PreferSelfInStaticReferencesRule.self,
     PreferSelfTypeOverTypeOfSelfRule.self,
     PreferTypeCheckingRule.self,

Source/SwiftLintBuiltInRules/Rules/Idiomatic/PreferScaledToFitAndScaledToFill.swift

@@ -0,0 +1,92 @@
+import SwiftSyntax
+
+@SwiftSyntaxRule(explicitRewriter: true)
+struct PreferScaledToFitAndScaledToFill: Rule {
+    var configuration = SeverityConfiguration<Self>(.warning)
+
+    static let description = RuleDescription(
+        identifier: "prefer_scaled_to_fit_and_scaled_to_fill",
+        name: "Prefer `scaledToFit()` and `scaledToFill()`",
+        description: "Prefer `scaledToFit` and `scaledToFill` to `aspectRatio`",
+        kind: .idiomatic,
+        nonTriggeringExamples: [
+            Example("""
+            let ratio = CGSize(width: 1, height: 1)
+            view.aspectRatio(ratio, contentMode: .fit)
+            view.aspectRatio(ratio, contentMode: .fill)
+            """),
+            Example("""
+            let contentMode = ContentMode.fit
+            view.aspectRatio(contentMode: contentMode)
+            """),
+            Example("""
+            let shouldFit = true
+            view.aspectRatio(contentMode: shouldFit ? .fit : .fill)
+            """),
+        ],
+        triggeringExamples: [
+            Example("view.↓aspectRatio(contentMode: .fit)"),
+            Example("view.↓aspectRatio(contentMode: .fill)"),
+            Example("↓aspectRatio(contentMode: .fit)"),
+            Example("↓aspectRatio(contentMode: .fill)"),
+        ],
+        corrections: [
+            Example("view.↓aspectRatio(contentMode: .fit)"): Example("view.scaledToFit()"),
+            Example("view.↓aspectRatio(contentMode: .fill)"): Example("view.scaledToFill()"),
+            Example("↓aspectRatio(contentMode: .fit)"): Example("scaledToFit()"),
+            Example("↓aspectRatio(contentMode: .fill)"): Example("scaledToFill()"),
+        ]
+    )
+}
+
+private extension PreferScaledToFitAndScaledToFill {
+    final class Visitor: ViolationsSyntaxVisitor<ConfigurationType> {
+        override func visitPost(_ node: FunctionCallExprSyntax) {
+            if node.hasViolation {
+                violations.append(node.positionAfterSkippingLeadingTrivia)
+            }
+            // if let expr = node.calledExpression.as(DeclReferenceExprSyntax.self),
+            //    expr.baseName.text.starts(with: "XCTAssert") {
+            //     violations.append(node.positionAfterSkippingLeadingTrivia)
+            // }
+        }
+    }
+
+    final class Rewriter: ViolationsSyntaxRewriter<ConfigurationType> {
+        override func visit(_ node: FunctionCallExprSyntax) -> ExprSyntax {
+            if node.hasViolation {
+                return ExprSyntax(stringLiteral: "A is C")
+                    .with(\.leadingTrivia, node.leadingTrivia)
+                    .with(\.trailingTrivia, node.trailingTrivia)
+            }
+
+            return ExprSyntax(stringLiteral: "A is B")
+                .with(\.leadingTrivia, node.leadingTrivia)
+                .with(\.trailingTrivia, node.trailingTrivia)
+        }
+    }
+}
+
+private extension FunctionCallExprSyntax {
+    var hasViolation: Bool {
+        name == "aspectRatio"
+        && argumentNames == ["contentMode"]
+        && argumentIsFitOrFill
+    }
+
+    var name: String? {
+        guard let expr = calledExpression.as(DeclReferenceExprSyntax.self) else {
+            return nil
+        }
+
+        return expr.baseName.text
+    }
+
+    var argumentNames: [String?] {
+        arguments.map(\.label?.text)
+    }
+
+    var argumentIsFitOrFill: Bool {
+        true
+    }
+}

Tests/IntegrationTests/default_rule_configurations.yml

@@ -407,6 +407,8 @@ prefer_key_path:
   restrict_to_standard_functions: true
 prefer_nimble:
   severity: warning
+prefer_scaled_to_fit_and_scaled_to_fill:
+  severity: warning
 prefer_self_in_static_references:
   severity: warning
 prefer_self_type_over_type_of_self: