[CSDiagnostics] Tweak candidate note text for arg mismatch

Number the parameters starting at 1 in order to
match other diagnostics such as
diag::missing_argument_positional, and change the
text to make it explicit that we're referring to
the parameter position (rather than argument
position).

Author: hamishknight

include/swift/AST/DiagnosticsSema.def

@@ -381,7 +381,7 @@ ERROR(cannot_convert_argument_value,none,
       (Type,Type))
 
 NOTE(candidate_has_invalid_argument_at_position,none,
-     "candidate expects value of type %0 at position #%1",
+     "candidate expects value of type %0 for parameter #%1",
      (Type, unsigned))
 
 ERROR(cannot_convert_array_to_variadic,none,

lib/Sema/CSDiagnostics.cpp

@@ -5042,13 +5042,9 @@ bool ArgumentMismatchFailure::diagnoseAsError() {
 }
 
 bool ArgumentMismatchFailure::diagnoseAsNote() {
-  auto *locator = getLocator();
-  auto argToParam = locator->findFirst<LocatorPathElt::ApplyArgToParam>();
-  assert(argToParam);
-
   if (auto *callee = getCallee()) {
     emitDiagnostic(callee, diag::candidate_has_invalid_argument_at_position,
-                   getToType(), argToParam->getParamIdx());
+                   getToType(), getParamPosition());
     return true;
   }
 

test/Constraints/closures.swift

@@ -349,8 +349,8 @@ takeVoidVoidFn { () -> Void in
 }
 
 // <rdar://problem/19997471> Swift: Incorrect compile error when calling a function inside a closure
-func f19997471(_ x: String) {} // expected-note {{candidate expects value of type 'String' at position #0}}
-func f19997471(_ x: Int) {}    // expected-note {{candidate expects value of type 'Int' at position #0}}
+func f19997471(_ x: String) {} // expected-note {{candidate expects value of type 'String' for parameter #1}}
+func f19997471(_ x: Int) {}    // expected-note {{candidate expects value of type 'Int' for parameter #1}}
 
 func someGeneric19997471<T>(_ x: T) {
   takeVoidVoidFn {

test/Constraints/construction.swift

@@ -16,9 +16,9 @@ enum Z {
 
   init() { self = .none }
   init(_ c: UnicodeScalar) { self = .char(c) }
-  // expected-note@-1 2 {{candidate expects value of type 'UnicodeScalar' (aka 'Unicode.Scalar') at position #0}}
+  // expected-note@-1 2 {{candidate expects value of type 'UnicodeScalar' (aka 'Unicode.Scalar') for parameter #1}}
   init(_ s: String) { self = .string(s) }
-  // expected-note@-1 2 {{candidate expects value of type 'String' at position #0}}
+  // expected-note@-1 2 {{candidate expects value of type 'String' for parameter #1}}
   init(_ x: Int, _ y: Int) { self = .point(x, y) }
 }
 

test/Constraints/diagnostics.swift

@@ -1069,7 +1069,7 @@ func SR_6272_c() {
 struct SR_6272_D: ExpressibleByIntegerLiteral {
   typealias IntegerLiteralType = Int
   init(integerLiteral: Int) {}
-  static func +(lhs: SR_6272_D, rhs: Int) -> Float { return 42.0 } // expected-note 2 {{candidate expects value of type 'Int' at position #1}}
+  static func +(lhs: SR_6272_D, rhs: Int) -> Float { return 42.0 } // expected-note 2 {{candidate expects value of type 'Int' for parameter #2}}
 }
 
 func SR_6272_d() {

test/Constraints/overload.swift

@@ -3,9 +3,9 @@
 func markUsed<T>(_ t: T) {}
 
 func f0(_: Float) -> Float {}
-// expected-note@-1 {{candidate expects value of type 'Float' at position #0}}
+// expected-note@-1 {{candidate expects value of type 'Float' for parameter #1}}
 func f0(_: Int) -> Int {}
-// expected-note@-1 {{candidate expects value of type 'Int' at position #0}}
+// expected-note@-1 {{candidate expects value of type 'Int' for parameter #1}}
 
 func f1(_: Int) {}
 

test/Generics/function_defs.swift

@@ -74,8 +74,8 @@ protocol Overload {
   associatedtype B
   func getA() -> A
   func getB() -> B
-  func f1(_: A) -> A // expected-note {{candidate expects value of type 'OtherOvl.A' at position #0}}
-  func f1(_: B) -> B // expected-note {{candidate expects value of type 'OtherOvl.B' at position #0}}
+  func f1(_: A) -> A // expected-note {{candidate expects value of type 'OtherOvl.A' for parameter #1}}
+  func f1(_: B) -> B // expected-note {{candidate expects value of type 'OtherOvl.B' for parameter #1}}
   func f2(_: Int) -> A // expected-note{{found this candidate}}
   func f2(_: Int) -> B // expected-note{{found this candidate}}
   func f3(_: Int) -> Int // expected-note {{found this candidate}}

test/decl/subscript/subscripting.swift

@@ -393,9 +393,9 @@ func testSubscript1(_ s1 : SubscriptTest1) {
 }
 
 struct SubscriptTest2 {
-  subscript(a : String, b : Int) -> Int { return 0 } // expected-note {{candidate expects value of type 'Int' at position #1}}
+  subscript(a : String, b : Int) -> Int { return 0 } // expected-note {{candidate expects value of type 'Int' for parameter #2}}
   // expected-note@-1 {{declared here}}
-    subscript(a : String, b : String) -> Int { return 0 } // expected-note {{candidate expects value of type 'String' at position #1}}
+    subscript(a : String, b : String) -> Int { return 0 } // expected-note {{candidate expects value of type 'String' for parameter #2}}
 }
 
 func testSubscript1(_ s2 : SubscriptTest2) {

validation-test/compiler_crashers_2_fixed/0146-rdar38309176.swift

@@ -1,7 +1,7 @@
 // RUN: %target-typecheck-verify-swift
 
-func foo(_ msg: Int) {}    // expected-note {{candidate expects value of type 'Int' at position #0}}
-func foo(_ msg: Double) {} // expected-note {{candidate expects value of type 'Double' at position #0}}
+func foo(_ msg: Int) {}    // expected-note {{candidate expects value of type 'Int' for parameter #1}}
+func foo(_ msg: Double) {} // expected-note {{candidate expects value of type 'Double' for parameter #1}}
 
 func rdar38309176(_ errors: inout [String]) {
   foo("error: \(errors[0])") // expected-error {{no exact matches in call to global function 'foo'}}