Sema: Redeclaration checking should not mark implicit decls as invalid

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -754,44 +754,48 @@ CheckRedeclarationRequest::evaluate(Evaluator &eval, ValueDecl *current) const {
             declToDiagnose->diagnose(diag::invalid_redecl_implicit,
                                      current->getDescriptiveKind(),
                                      isProtocolRequirement, other->getName());
-          }
 
-          // Emit a specialized note if the one of the declarations is
-          // the backing storage property ('_foo') or projected value
-          // property ('$foo') for a wrapped property. The backing or
-          // projected var has the same source location as the wrapped
-          // property we diagnosed above, so we don't need to extract
-          // the original property.
-          const VarDecl *varToDiagnose = nullptr;
-          auto kind = PropertyWrapperSynthesizedPropertyKind::Backing;
-          if (auto currentVD = dyn_cast<VarDecl>(current)) {
-            if (auto currentKind =
-                    currentVD->getPropertyWrapperSynthesizedPropertyKind()) {
-              varToDiagnose = currentVD;
-              kind = *currentKind;
+            // Emit a specialized note if the one of the declarations is
+            // the backing storage property ('_foo') or projected value
+            // property ('$foo') for a wrapped property. The backing or
+            // projected var has the same source location as the wrapped
+            // property we diagnosed above, so we don't need to extract
+            // the original property.
+            const VarDecl *varToDiagnose = nullptr;
+            auto kind = PropertyWrapperSynthesizedPropertyKind::Backing;
+            if (auto currentVD = dyn_cast<VarDecl>(current)) {
+              if (auto currentKind =
+                      currentVD->getPropertyWrapperSynthesizedPropertyKind()) {
+                varToDiagnose = currentVD;
+                kind = *currentKind;
+              }
             }
-          }
-          if (auto otherVD = dyn_cast<VarDecl>(other)) {
-            if (auto otherKind =
-                    otherVD->getPropertyWrapperSynthesizedPropertyKind()) {
-              varToDiagnose = otherVD;
-              kind = *otherKind;
+            if (auto otherVD = dyn_cast<VarDecl>(other)) {
+              if (auto otherKind =
+                      otherVD->getPropertyWrapperSynthesizedPropertyKind()) {
+                varToDiagnose = otherVD;
+                kind = *otherKind;
+              }
+            }
+
+            if (varToDiagnose) {
+              assert(declToDiagnose);
+              varToDiagnose->diagnose(
+                  diag::invalid_redecl_implicit_wrapper, varToDiagnose->getName(),
+                  kind == PropertyWrapperSynthesizedPropertyKind::Backing);
             }
-          }
 
-          if (varToDiagnose) {
-            varToDiagnose->diagnose(
-                diag::invalid_redecl_implicit_wrapper, varToDiagnose->getName(),
-                kind == PropertyWrapperSynthesizedPropertyKind::Backing);
+            current->setInvalid();
           }
         } else {
           ctx.Diags.diagnoseWithNotes(
             current->diagnose(diag::invalid_redecl,
                               current->getName()), [&]() {
             other->diagnose(diag::invalid_redecl_prev, other->getName());
           });
+
+          current->setInvalid();
         }
-        current->setInvalid();
       }
 
       // Make sure we don't do this checking again for the same decl. We also

validation-test/compiler_crashers_2_fixed/rdar67259506.swift

@@ -0,0 +1,29 @@
+// RUN: %target-swift-frontend -emit-ir %s
+
+public func foo<T : P & Q>(_: T, _: S<T>.A) {}
+
+public protocol P {
+  associatedtype A
+
+  func foo() -> A
+}
+
+public protocol Q {
+  associatedtype A
+
+  func bar() -> A
+}
+
+public struct S<T> {}
+
+extension S : P where T : P {
+  public func foo() -> Int {
+    return 0
+  }
+}
+
+extension S : Q where T : Q {
+  public func bar() -> Int {
+    return 0
+  }
+}