Sema: Fix diagnoseConformanceImpliedByConditionalConformance() for tuple conformances

Author: slavapestov

lib/Sema/TypeCheckProtocol.cpp

@@ -1901,13 +1901,12 @@ void MultiConformanceChecker::checkAllConformances() {
 static void diagnoseConformanceImpliedByConditionalConformance(
     DiagnosticEngine &Diags, NormalProtocolConformance *conformance,
     NormalProtocolConformance *implyingConf, bool issueFixit) {
-  Type T = conformance->getType();
   auto proto = conformance->getProtocol();
   Type protoType = proto->getDeclaredInterfaceType();
   auto implyingProto = implyingConf->getProtocol()->getDeclaredInterfaceType();
   auto loc = implyingConf->getLoc();
   Diags.diagnose(loc, diag::conditional_conformances_cannot_imply_conformances,
-                 T, implyingProto, protoType);
+                 conformance->getType(), implyingProto, protoType);
 
   if (!issueFixit)
     return;
@@ -1949,11 +1948,7 @@ static void diagnoseConformanceImpliedByConditionalConformance(
     llvm::raw_svector_ostream prefixStream(prefix);
     llvm::raw_svector_ostream suffixStream(suffix);
 
-    ValueDecl *decl = T->getAnyNominal();
-    if (!decl)
-      decl = T->getAnyGeneric();
-
-    prefixStream << "extension " << decl->getName() << ": " << protoType << " ";
+    prefixStream << "extension " << ext->getExtendedType() << ": " << protoType << " ";
     suffixStream << " {\n"
                  << indent << extraIndent << "<#witnesses#>\n"
                  << indent << "}\n\n"

test/Generics/tuple-conformances.swift

@@ -3,19 +3,45 @@
 // Because of -enable-experimental-feature TupleConformances
 // REQUIRES: asserts
 
+extension () {
+  // expected-error@-1 {{tuple extension must be written as extension of '(repeat each Element)'}}
+  // expected-error@-2 {{tuple extension must declare conformance to exactly one protocol}}
+}
+
+typealias Tuple<each Element> = (repeat each Element)
+
+protocol Q {}
+
+class C {}
+
+extension Tuple: Q where repeat each Element: Collection, repeat (each Element).Element == (each Element).Index, repeat (each Element).Indices: AnyObject, repeat (each Element).SubSequence: C {}
+// expected-error@-1 {{tuple extension must require that 'each Element' conforms to 'Q'}}
+// expected-error@-2 {{tuple extension cannot require that 'each Element' conforms to 'Collection'}}
+// expected-error@-3 {{tuple extension cannot require that '(each Element).Element' is the same type as '(each Element).Index'}}
+// expected-error@-4 {{tuple extension cannot require that '(each Element).Indices' conforms to 'AnyObject'}}
+// expected-error@-5 {{tuple extension cannot require that '(each Element).SubSequence' subclasses 'C'}}
+
+protocol Base1 {}
+protocol Derived1: Base1 {}
+
+extension Tuple: Derived1 where repeat each Element: Derived1 {}
+// expected-error@-1 {{conditional conformance of type '(repeat each Element)' to protocol 'Derived1' does not imply conformance to inherited protocol 'Base1'}} // FIXME: crappy error
+// expected-note@-2 {{did you mean to explicitly state the conformance like 'extension (repeat each Element): Base1 where ...'?}}
+// expected-error@-3 {{tuple extension must declare conformance to exactly one protocol}}
+
+protocol Base2 {}
+protocol Derived2: Base2 {}
+
+extension Tuple: Derived2 {}
+// expected-error@-1 {{tuple extension must declare conformance to exactly one protocol}} // FIXME: crappy error
+
 protocol P {
   associatedtype A
   associatedtype B
 
   func f()
 }
 
-extension () {}
-// expected-error@-1 {{tuple extension must be written as extension of '(repeat each Element)'}}
-// FIXME: Inaccurate
-
-typealias Tuple<each Element> = (repeat each Element)
-
 extension Tuple: P where repeat each Element: P {
   typealias A = (repeat (each Element).A)
   typealias B = Float