Merge pull request #18527 from xedin/rdar-42678836

[CSRanking] Fix solution filtering not to erase everything when set i…

Author: xedin

lib/Sema/CSRanking.cpp

@@ -1214,6 +1214,14 @@ ConstraintSystem::findBestSolution(SmallVectorImpl<Solution> &viable,
     return bestIdx;
   }
 
+  // If there is not a single "better" than others
+  // solution, which probably means that solutions
+  // were incomparable, let's just keep the original
+  // list instead of removing everything, even if we
+  // are asked to "minimize" the result.
+  if (losers.size() == viable.size())
+    return None;
+
   // The comparison was ambiguous. Identify any solutions that are worse than
   // any other solution.
   for (unsigned i = 0, n = viable.size(); i != n; ++i) {

test/Constraints/patterns.swift

@@ -374,10 +374,10 @@ func test8347() -> String {
       return ""
     }
 
-    func h() -> String {
+    func h() -> String { // expected-note {{found this candidate}}
       return ""
     }
-    func h() -> Double {
+    func h() -> Double { // expected-note {{found this candidate}}
       return 3.0
     }
     func h() -> Int? { //expected-note{{found this candidate}}

test/Constraints/rdar42678836.swift

@@ -0,0 +1,6 @@
+// RUN: %target-typecheck-verify-swift
+
+func foo(chr: Character) -> String {
+  return String(repeating: String(chr)) // expected-error {{argument labels '(repeating:)' do not match any available overloads}}
+  // expected-note@-1 {{overloads for 'String' exist with these partially matching parameter lists}}
+}

test/expr/expressions.swift

@@ -550,8 +550,8 @@ struct SpecialPi {} // Type with no implicit construction.
 
 var pi_s: SpecialPi
 
-func getPi() -> Float {} // expected-note 3 {{found this candidate}}
-func getPi() -> Double {} // expected-note 3 {{found this candidate}}
+func getPi() -> Float {}
+func getPi() -> Double {}
 func getPi() -> SpecialPi {}
 
 enum Empty { }
@@ -573,12 +573,12 @@ func conversionTest(_ a: inout Double, b: inout Int) {
   var pi_d1 = Double(pi_d)
   var pi_s1 = SpecialPi(pi_s) // expected-error {{argument passed to call that takes no arguments}}
 
-  var pi_f2 = Float(getPi()) // expected-error {{ambiguous use of 'getPi()'}}
-  var pi_d2 = Double(getPi()) // expected-error {{ambiguous use of 'getPi()'}}
+  var pi_f2 = Float(getPi()) // expected-error {{ambiguous use of 'init'}}
+  var pi_d2 = Double(getPi()) // expected-error {{ambiguous use of 'init'}}
   var pi_s2: SpecialPi = getPi() // no-warning
 
   var float = Float.self
-  var pi_f3 = float.init(getPi()) // expected-error {{ambiguous use of 'getPi()'}}
+  var pi_f3 = float.init(getPi()) // expected-error {{ambiguous use of 'init'}}
   var pi_f4 = float.init(pi_f)
 
   var e = Empty(f)

validation-test/IDE/crashers_2_fixed/0022-rdar42678836.swift

@@ -0,0 +1,5 @@
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=COMPLETE -source-filename=%s
+
+public func * (lhs: Int, rhs: Character) -> String {
+  return String(repeating: String(rhs), count #^COMPLETE^#: lhs)
+}