Improve unused parameter location identification. Closes #243

Author: ileitch

CHANGELOG.md

@@ -10,7 +10,7 @@
 
 ##### Bug Fixes
 
-- None.
+- Improve unused parameter location identification.
 
 ## 2.3.2 (2020-12-10)
 

Sources/PeripheryKit/Syntax/UnusedParameterParser.swift

@@ -232,14 +232,14 @@ struct UnusedParameterParser {
             metatype = metatypeSyntax.description
         }
 
-        // Position is off by one, advance forward so that we can identify the correct line of param lists that span
-        // multiple lines.
-        let position = AbsolutePosition(utf8Offset: syntax.position.utf8Offset + 1)
+        let positionSyntax: SyntaxProtocol = (syntax.secondName ?? syntax.firstName) ?? syntax
+        let absolutePosition = AbsolutePosition(utf8Offset: positionSyntax.position.utf8Offset + positionSyntax.leadingTriviaLength.utf8Length)
+        let location = sourceLocation(of: absolutePosition)
 
         return Parameter(firstName: syntax.firstName?.text,
                          secondName: syntax.secondName?.text,
                          metatype: metatype,
-                         location: sourceLocation(of: position))
+                         location: location)
     }
 
     private func parse<T>(closureExpr syntax: ClosureExprSyntax, _ collector: Collector<T>?) -> Closure? {

Tests/PeripheryTests/Syntax/UnusedParameterTest.swift

@@ -115,6 +115,23 @@ class UnusedParameterTest: XCTestCase {
         XCTAssertUsed("param", of: "init(param:)")
     }
 
+    func testParameterPosition() {
+        analyze()
+        let function = functions.first!
+
+        let param1 = function.parameters.first { $0.name == "param1" }!
+        try XCTAssertEqual(XCTUnwrap(param1.location.line), 4)
+        try XCTAssertEqual(XCTUnwrap(param1.location.column), 17)
+
+        let param2 = function.parameters.first { $0.name == "param2" }!
+        try XCTAssertEqual(XCTUnwrap(param2.location.line), 4)
+        try XCTAssertEqual(XCTUnwrap(param2.location.column), 38)
+
+        let param3 = function.parameters.first { $0.name == "param3" }!
+        try XCTAssertEqual(XCTUnwrap(param3.location.line), 4)
+        try XCTAssertEqual(XCTUnwrap(param3.location.column), 56)
+    }
+
     func testInitializerPosition() {
         analyze()
 
@@ -134,10 +151,30 @@ class UnusedParameterTest: XCTestCase {
     func testMultiLineParameterPosition() {
         analyze()
         let function = functions.first!
+
         let param1 = function.parameters.first { $0.name == "param1" }!
-        let param2 = function.parameters.first { $0.name == "param2" }!
         try XCTAssertEqual(XCTUnwrap(param1.location.line), 4)
+        try XCTAssertEqual(XCTUnwrap(param1.location.column), 17)
+
+        let param2 = function.parameters.first { $0.name == "param2" }!
         try XCTAssertEqual(XCTUnwrap(param2.location.line), 5)
+        try XCTAssertEqual(XCTUnwrap(param2.location.column), 17)
+
+        let param3 = function.parameters.first { $0.name == "param3" }!
+        try XCTAssertEqual(XCTUnwrap(param3.location.line), 7)
+        try XCTAssertEqual(XCTUnwrap(param3.location.column), 17)
+
+        let param4 = function.parameters.first { $0.name == "param4" }!
+        try XCTAssertEqual(XCTUnwrap(param4.location.line), 8)
+        try XCTAssertEqual(XCTUnwrap(param4.location.column), 19)
+
+        let param5 = function.parameters.first { $0.name == "param5" }!
+        try XCTAssertEqual(XCTUnwrap(param5.location.line), 9)
+        try XCTAssertEqual(XCTUnwrap(param5.location.column), 22)
+
+        let param6 = function.parameters.first { $0.name == "param6" }!
+        try XCTAssertEqual(XCTUnwrap(param6.location.line), 11)
+        try XCTAssertEqual(XCTUnwrap(param6.location.column), 21)
     }
 
     func testIBActionAnnotatedFunction() {

Tests/SyntaxFixtures/testMultiLineParameterPosition.swift

@@ -2,5 +2,12 @@ import Foundation
 
 class SyntaxFixture12 {
     func myFunc(param1: String,
-                param2: String) {}
+                param2: String,
+                // Some comment.
+                param3: String,
+                _ param4: String,
+                with param5: String,
+                _ // Another comment.
+                    param6: String
+                ) {}
 }

Tests/SyntaxFixtures/testParameterPosition.swift

@@ -0,0 +1,5 @@
+import Foundation
+
+class SyntaxFixture23 {
+    func myFunc(param1: String, with param2: String, _ param3: String) {}
+}