Merge pull request #5865 from DougGregor/unsatisfiable-req-swift-3

Author: swift-ci

include/swift/AST/DiagnosticsSema.def

@@ -1291,6 +1291,10 @@ ERROR(requirement_restricts_self,none,
       "%0 requirement %1 cannot add constraint '%2%select{:|:| ==|:}3 %4' on "
       "'Self'",
       (DescriptiveDeclKind, DeclName, StringRef, unsigned, StringRef))
+WARNING(requirement_restricts_self_swift3,none,
+        "adding constraint '%2%select{:|:| ==|:}3 %4' on 'Self' via %0 "
+        "requirement %1 is deprecated in Swift 3",
+        (DescriptiveDeclKind, DeclName, StringRef, unsigned, StringRef))
 ERROR(witness_argument_name_mismatch,none,
       "%select{method|initializer}0 %1 has different argument names from those "
       "required by protocol %2 (%3)", (bool, DeclName, Type, DeclName))

lib/Sema/TypeCheckGeneric.cpp

@@ -529,13 +529,17 @@ TypeChecker::validateGenericFuncSignature(AbstractFunctionDecl *func) {
           req.getFirstType()->is<GenericTypeParamType>())
         continue;
 
-      diagnose(func, diag::requirement_restricts_self,
+      diagnose(func,
+               Context.LangOpts.EffectiveLanguageVersion[0] >= 4
+                 ? diag::requirement_restricts_self
+                 : diag::requirement_restricts_self_swift3,
                func->getDescriptiveKind(), func->getFullName(),
                req.getFirstType().getString(),
                static_cast<unsigned>(req.getKind()),
                req.getSecondType().getString());
 
-      invalid = true;
+      if (Context.LangOpts.EffectiveLanguageVersion[0] >= 4)
+        invalid = true;
     }
   }
 

test/Compatibility/unsatisfiable_req.swift

@@ -0,0 +1,24 @@
+// RUN: %target-parse-verify-swift -swift-version 3
+
+protocol P {
+  associatedtype A
+  associatedtype B
+
+  func f<T: P>(_: T) where T.A == Self.A, T.A == Self.B // expected-warning{{adding constraint 'Self.A == Self.B' on 'Self' via instance method requirement 'f' is deprecated}}
+  // expected-note@-1{{protocol requires function 'f' with type '<T> (T) -> ()'; do you want to add a stub?}}
+}
+
+extension P {
+  func f<T: P>(_: T) where T.A == Self.A, T.A == Self.B { } // expected-note{{candidate has non-matching type '<Self, T> (T) -> ()'}}
+}
+
+struct X : P { // expected-error{{type 'X' does not conform to protocol 'P'}}
+  typealias A = X
+  typealias B = Int
+}
+
+struct Y : P {
+  typealias A = Y
+  typealias B = Y
+}
+

test/decl/protocol/req/unsatisfiable.swift

@@ -1,4 +1,4 @@
-// RUN: %target-parse-verify-swift
+// RUN: %target-parse-verify-swift -swift-version 4
 
 protocol P {
   associatedtype A

validation-test/compiler_crashers/28504-anonymous-namespace-verifier-verifychecked-swift-type-llvm-smallptrset-swift-arc.swift

@@ -6,5 +6,6 @@
 // See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
 // RUN: not --crash %target-swift-frontend %s -emit-ir
+// REQUIRES: non_escaping_type_variables
 {{}
 return.h.h == Int