---

yaml
---
r: 317429
b: refs/heads/master-rebranch
c: e0557d7
h: refs/heads/master
i:
  317427: 229f7b0

Author: swift-ci

[refs]

@@ -1457,4 +1457,4 @@ refs/tags/swift-DEVELOPMENT-SNAPSHOT-2019-08-02-a: ddd2b2976aa9bfde5f20fe37f6bd2
 refs/tags/swift-DEVELOPMENT-SNAPSHOT-2019-08-03-a: 171cc166f2abeb5ca2a4003700a8a78a108bd300
 refs/heads/benlangmuir-patch-1: baaebaf39d52f3bf36710d4fe40cf212e996b212
 refs/heads/i-do-redeclare: 8c4e6d5de5c1e3f0a2cedccf319df713ea22c48e
-refs/heads/master-rebranch: 0e5f845a07ed2479bdb9ec43266c2e7fe8ba844b
+refs/heads/master-rebranch: e0557d725c7326d1c01b40d5b599fa024cf631e9

branches/master-rebranch/lib/Sema/TypeChecker.cpp

@@ -300,6 +300,28 @@ static void prepareGenericParamList(GenericParamList *genericParams) {
     prepareGenericParamList(outerGenericParams);
 }
 
+/// Ensure that the outer generic parameters of the given generic
+/// context have been configured.
+static void configureOuterGenericParams(const GenericContext *dc) {
+  auto genericParams = dc->getGenericParams();
+  if (!genericParams) return;
+
+  if (genericParams->getOuterParameters()) return;
+
+  DeclContext *outerDC = dc->getParent();
+  while (!outerDC->isModuleScopeContext()) {
+    if (auto outerDecl = outerDC->getAsDecl()) {
+      if (auto outerGenericDC = outerDecl->getAsGenericContext()) {
+        genericParams->setOuterParameters(outerGenericDC->getGenericParams());
+        configureOuterGenericParams(outerGenericDC);
+        return;
+      }
+    }
+
+    outerDC = outerDC->getParent();
+  }
+}
+
 /// Bind the given extension to the given nominal type.
 static void bindExtensionToNominal(ExtensionDecl *ext,
                                    NominalTypeDecl *nominal) {
@@ -313,10 +335,7 @@ static void bindExtensionToNominal(ExtensionDecl *ext,
     ext->setGenericParams(genericParams);
   } else if (auto genericParams = nominal->getGenericParamsOfContext()) {
     // Make sure the generic parameters are set up.
-    if (auto nominalGenericParams = nominal->getGenericParams()) {
-      nominalGenericParams->setOuterParameters(
-        nominal->getDeclContext()->getGenericParamsOfContext());
-    }
+    configureOuterGenericParams(nominal);
 
     // Clone the generic parameter list of a generic type.
     prepareGenericParamList(genericParams);

branches/master-rebranch/test/decl/ext/generic.swift

@@ -175,3 +175,20 @@ func foo() {
     func foo() -> Element.AssocType {}
   }
 }
+
+// Deeply nested
+protocol P6 {
+  associatedtype Assoc1
+  associatedtype Assoc2
+}
+
+struct A<T, U, V> {
+  struct B<W, X, Y> {
+    struct C<Z: P6> {
+    }
+  }
+}
+
+extension A.B.C where T == V, X == Z.Assoc2 {
+  func f() { }
+}