Merge pull request #27608 from xedin/autoclosure-ctx-mismatch

[Diagnostics] Extend use of argument mismatch fix to `autoclosure` pa…

Author: xedin

lib/Sema/CSSimplify.cpp

@@ -3007,13 +3007,38 @@ bool ConstraintSystem::repairFailures(
     if (repairByInsertingExplicitCall(lhs, rhs))
       return true;
 
-    auto result = matchTypes(lhs, rhs, ConstraintKind::ArgumentConversion,
-        TypeMatchFlags::TMF_ApplyingFix,
-        locator.withPathElement(ConstraintLocator::FunctionArgument));
+    auto isPointerType = [](Type type) -> bool {
+      return bool(
+          type->lookThroughAllOptionalTypes()->getAnyPointerElementType());
+    };
 
-    if (result.isSuccess())
-      conversionsOrFixes.push_back(AllowAutoClosurePointerConversion::create(
-          *this, lhs, rhs, getConstraintLocator(locator)));
+    // Let's see whether this is an implicit conversion to a pointer type
+    // which is invalid in @autoclosure context e.g. from `inout`, Array
+    // or String.
+    if (!isPointerType(lhs) && isPointerType(rhs)) {
+      auto result = matchTypes(
+          lhs, rhs, ConstraintKind::ArgumentConversion,
+          TypeMatchFlags::TMF_ApplyingFix,
+          locator.withPathElement(ConstraintLocator::FunctionArgument));
+
+      if (result.isSuccess())
+        conversionsOrFixes.push_back(AllowAutoClosurePointerConversion::create(
+            *this, lhs, rhs, getConstraintLocator(locator)));
+    }
+
+    // In situations like this:
+    //
+    // struct S<T> {}
+    // func foo(_: @autoclosure () -> S<Int>) {}
+    // foo(S<String>())
+    //
+    // Generic type conversion mismatch is a better fix which is going to
+    // point to the generic arguments that did not align properly.
+    if (hasConversionOrRestriction(ConversionRestrictionKind::DeepEquality))
+      break;
+
+    conversionsOrFixes.push_back(AllowArgumentMismatch::create(
+        *this, lhs, rhs, getConstraintLocator(locator)));
     break;
   }
 

test/Constraints/bridging.swift

@@ -285,7 +285,8 @@ 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?'}}{{21-21= as String?}}
+  var s: String = ns ?? "str" as String as String // expected-error{{'NSString' is not implicitly convertible to 'String'; did you mean to use 'as' to explicitly convert?}} {{19-19=(}} {{50-50=) as String}}
+  // expected-error@-1 {{cannot convert value of type 'String' to expected argument type 'NSString'}} {{50-50= as NSString}}
   var s2 = ns ?? "str" as String as String // expected-error {{cannot convert value of type 'String' to expected argument type 'NSString'}}{{43-43= as NSString}}
 
   let s3: NSString? = "str" as String? // expected-error {{cannot convert value of type 'String?' to specified type 'NSString?'}}{{39-39= as NSString?}}

test/attr/attr_autoclosure.swift

@@ -274,3 +274,10 @@ func autoclosure_param_returning_func_type() {
   func biz_5(_ fn: @escaping () -> (() -> Int)) { fiz(fn) } // Can't forward in Swift >= 5 mode
   // expected-error@-1 {{add () to forward @autoclosure parameter}} {{57-57=()}}
 }
+
+func test_autoclosure_with_generic_argument_mismatch() {
+  struct S<T> {} // expected-note {{arguments to generic parameter 'T' ('String' and 'Int') are expected to be equal}}
+  func foo(_: @autoclosure () -> S<Int>) {}
+
+  foo(S<String>()) // expected-error {{cannot convert value of type 'S<String>' to expected argument type 'S<Int>'}}
+}

test/decl/func/dynamic_self.swift

@@ -386,8 +386,7 @@ class Factory : FactoryPattern {
 
   convenience init(string: String) {
     self.init(factory: Factory(_string: string))
-    // expected-error@-1 {{incorrect argument label in call (have 'factory:', expected '_string:')}}
-    // FIXME: Bogus diagnostic
+    // expected-error@-1 {{cannot convert value of type 'Factory' to expected argument type 'Self'}}
   }
 }
 

test/expr/expressions.swift

@@ -774,14 +774,16 @@ func testNilCoalescePrecedence(cond: Bool, a: Int?, r: ClosedRange<Int>?) {
   // ?? should have higher precedence than logical operators like || and comparisons.
   if cond || (a ?? 42 > 0) {}  // Ok.
   if (cond || a) ?? 42 > 0 {}  // expected-error {{cannot be used as a boolean}} {{15-15=(}} {{16-16= != nil)}}
+  // expected-error@-1:12 {{cannot convert value of type 'Bool' to expected argument type 'Int?'}}
   if (cond || a) ?? (42 > 0) {}  // expected-error {{cannot be used as a boolean}} {{15-15=(}} {{16-16= != nil)}}
 
   if cond || a ?? 42 > 0 {}    // Parses as the first one, not the others.
 
 
   // ?? should have lower precedence than range and arithmetic operators.
   let r1 = r ?? (0...42) // ok
-  let r2 = (r ?? 0)...42 // not ok: expected-error {{cannot convert value of type 'Int' to expected argument type 'ClosedRange<Int>'}}
+  let r2 = (r ?? 0)...42 // not ok: expected-error 2 {{cannot convert value of type 'Int' to expected argument type 'ClosedRange<Int>'}}
+  // expected-error@-1 {{argument type 'ClosedRange<Int>' does not conform to expected type 'Comparable'}}
   let r3 = r ?? 0...42 // parses as the first one, not the second.