Merge pull request #14160 from xedin/rdar-36449760-5.0

Author: swift-ci

lib/Sema/ConstraintSystem.cpp

@@ -954,6 +954,29 @@ ConstraintSystem::getTypeOfReference(ValueDecl *value,
   return { valueType, valueType };
 }
 
+static NominalTypeDecl *getInnermostConformingDC(TypeChecker &TC,
+                                                 DeclContext *DC,
+                                                 ProtocolDecl *protocol) {
+  do {
+    if (DC->isTypeContext()) {
+      auto *NTD = DC->getAsNominalTypeOrNominalTypeExtensionContext();
+      auto type = NTD->getDeclaredType();
+
+      ConformanceCheckOptions options;
+      options |= ConformanceCheckFlags::InExpression;
+      options |= ConformanceCheckFlags::SuppressDependencyTracking;
+      options |= ConformanceCheckFlags::SkipConditionalRequirements;
+
+      auto result =
+          TC.conformsToProtocol(type, protocol, NTD->getDeclContext(), options);
+
+      if (result)
+        return NTD;
+    }
+  } while ((DC = DC->getParent()));
+
+  return nullptr;
+}
 /// Bind type variables for archetypes that are determined from
 /// context.
 ///
@@ -1015,8 +1038,18 @@ static void bindArchetypesFromContext(
       // parameters, or because this generic parameter was constrained
       // away into a concrete type.
       if (found != replacements.end()) {
+        Type contextTy;
+
+        if (genericEnv) {
+          contextTy = genericEnv->mapTypeIntoContext(paramTy);
+        } else {
+          auto *protocol = parentDC->getAsProtocolOrProtocolExtensionContext();
+          auto conformingDC = getInnermostConformingDC(cs.TC, cs.DC, protocol);
+          assert(conformingDC);
+          contextTy = conformingDC->getDeclaredTypeInContext();
+        }
+
         auto typeVar = found->second;
-        auto contextTy = genericEnv->mapTypeIntoContext(paramTy);
         cs.addConstraint(ConstraintKind::Bind, typeVar, contextTy,
                          locatorPtr);
       }

validation-test/compiler_crashers_2_fixed/0138-rdar36449760.swift

@@ -0,0 +1,41 @@
+// RUN: not %target-swift-frontend %s -typecheck
+
+protocol A {
+  var question: String { get }
+
+  struct B {
+    var answer: Int = 42
+
+    func foo(a: A) {
+      _ = a.question
+    }
+  }
+}
+
+class C : A {
+  var question: String = "ultimate question"
+
+  func foo() -> B {}
+  func bar() -> A.B {}
+  func baz(b: B) {
+    _ = b.answer
+  }
+}
+
+class D : A {
+  var question: String = ""
+
+  struct E {
+    func baz(b: B) {
+      _ = b.answer
+    }
+  }
+}
+
+class F<T> : A {
+  var question: String = ""
+
+  func foo(b: B) {
+    _ = b.answer
+  }
+}