Merge pull request #5239 from xedin/SR-1255

SR-1255: Improve diagnostic when one of the parameters marked as autoclosure

Author: rudkx

lib/Sema/CSDiag.cpp

@@ -1286,15 +1286,27 @@ CalleeCandidateInfo::evaluateCloseness(DeclContext *dc, Type candArgListType,
   bool mismatchesAreNearMisses = true;
 
   CalleeCandidateInfo::FailedArgumentInfo failureInfo;
-  
+
+  // Local function which extracts type from the parameter container.
+  auto getType = [](const CallArgParam &param) -> Type {
+    // If parameter is marked as @autoclosure, we are
+    // only interested in it's resulting type.
+    if (param.isAutoClosure()) {
+      if (auto fnType = param.Ty->getAs<AnyFunctionType>())
+        return fnType->getResult();
+    }
+
+    return param.Ty;
+  };
+
   for (unsigned i = 0, e = paramBindings.size(); i != e; ++i) {
     // Bindings specify the arguments that source the parameter.  The only case
     // this returns a non-singular value is when there are varargs in play.
     auto &bindings = paramBindings[i];
-    auto paramType = candArgs[i].Ty;
+    auto paramType = getType(candArgs[i]);
 
     for (auto argNo : bindings) {
-      auto argType = actualArgs[argNo].Ty;
+      auto argType = getType(actualArgs[argNo]);
       auto rArgType = argType->getRValueType();
 
       // If the argument has an unresolved type, then we're not actually
@@ -5264,7 +5276,7 @@ bool FailureDiagnosis::visitApplyExpr(ApplyExpr *callExpr) {
       argType = tupleTy;
     }
   }
-  
+
   // Get the expression result of type checking the arguments to the call
   // independently, so we have some idea of what we're working with.
   //

test/Constraints/bridging.swift

@@ -288,7 +288,7 @@ func rdar19836341(_ ns: NSString?, vns: NSString?) {
 // <rdar://problem/20029786> Swift compiler sometimes suggests changing "as!" to "as?!"
 func rdar20029786(_ ns: NSString?) {
   var s: String = ns ?? "str" as String as String // expected-error{{cannot convert value of type 'NSString?' to expected argument type 'String?'}}
-  var s2 = ns ?? "str" as String as String // expected-error {{binary operator '??' cannot be applied to operands of type 'NSString?' and 'String'}} expected-note{{}}
+  var s2 = ns ?? "str" as String as String // expected-error {{cannot convert value of type 'String' to expected argument type 'NSString'}}
 
   let s3: NSString? = "str" as String? // expected-error {{cannot convert value of type 'String?' to specified type 'NSString?'}}
 

test/Constraints/diagnostics.swift

@@ -671,8 +671,7 @@ func r24251022() {
 func overloadSetResultType(_ a : Int, b : Int) -> Int {
   // https://twitter.com/_jlfischer/status/712337382175952896
   // TODO: <rdar://problem/27391581> QoI: Nonsensical "binary operator '&&' cannot be applied to two 'Bool' operands"
-  return a == b && 1 == 2  // expected-error {{binary operator '&&' cannot be applied to two 'Bool' operands}}
-  // expected-note @-1 {{expected an argument list of type '(Bool, @autoclosure () throws -> Bool)'}}
+  return a == b && 1 == 2  // expected-error {{cannot convert return expression of type 'Bool' to return type 'Int'}}
 }
 
 // <rdar://problem/21523291> compiler error message for mutating immutable field is incorrect
@@ -733,9 +732,8 @@ class Foo23752537 {
 extension Foo23752537 {
   func isEquivalent(other: Foo23752537) {
     // TODO: <rdar://problem/27391581> QoI: Nonsensical "binary operator '&&' cannot be applied to two 'Bool' operands"
-    // expected-error @+1 {{binary operator '&&' cannot be applied to two 'Bool' operands}}
+    // expected-error @+1 {{unexpected non-void return value in void function}}
     return (self.title != other.title && self.message != other.message)
-    // expected-note @-1 {{expected an argument list of type '(Bool, @autoclosure () throws -> Bool)'}}
   }
 }
 
@@ -815,3 +813,11 @@ r27212391(a: 1, 3, y: 5)    // expected-error {{missing argument label 'x' in ca
 r27212391(1, x: 3, y: 5)    // expected-error {{missing argument label 'a' in call}}
 r27212391(a: 1, y: 3, x: 5) // expected-error {{argument 'x' must precede argument 'y'}}
 r27212391(a: 1, 3, x: 5)    // expected-error {{argument 'x' must precede unnamed argument #2}}
+
+// SR-1255
+func foo1255_1() {
+  return true || false // expected-error {{unexpected non-void return value in void function}}
+}
+func foo1255_2() -> Int {
+  return true || false // expected-error {{cannot convert return expression of type 'Bool' to return type 'Int'}}
+}

test/expr/expressions.swift

@@ -735,8 +735,7 @@ func testNilCoalescePrecedence(cond: Bool, a: Int?, r: CountableClosedRange<Int>
 
   // ?? should have lower precedence than range and arithmetic operators.
   let r1 = r ?? (0...42) // ok
-  let r2 = (r ?? 0)...42 // not ok: expected-error {{binary operator '??' cannot be applied to operands of type 'CountableClosedRange<Int>?' and 'Int'}}
-  // expected-note @-1 {{overloads for '??' exist with these partially matching parameter lists:}}
+  let r2 = (r ?? 0)...42 // not ok: expected-error {{cannot convert value of type 'Int' to expected argument type 'CountableClosedRange<Int>'}}
   let r3 = r ?? 0...42 // parses as the first one, not the second.