From da80c42a762daffc87000ceddd3c74fa8cf5dbb8 Mon Sep 17 00:00:00 2001
From: Slava Pestov <spestov@apple.com>
Date: Wed, 21 Jun 2017 16:03:21 -0700
Subject: [PATCH] Sema: Don't infer 'dynamic' for static methods and properties

Otherwise, can crash in the AST verifier.

Fixes <rdar://problem/32862136>.
---
 lib/Sema/TypeCheckDecl.cpp         | 23 +++++++++++++++++++----
 test/attr/attr_dynamic_infer.swift |  8 +++++++-
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/lib/Sema/TypeCheckDecl.cpp b/lib/Sema/TypeCheckDecl.cpp
index 0d2ae5f933b41..337ae036188dd 100644
--- a/lib/Sema/TypeCheckDecl.cpp
+++ b/lib/Sema/TypeCheckDecl.cpp
@@ -1245,12 +1245,14 @@ static void validatePatternBindingEntries(TypeChecker &tc,
 
 void swift::makeFinal(ASTContext &ctx, ValueDecl *D) {
   if (D && !D->isFinal()) {
+    assert(!D->isDynamic());
     D->getAttrs().add(new (ctx) FinalAttr(/*IsImplicit=*/true));
   }
 }
 
 void swift::makeDynamic(ASTContext &ctx, ValueDecl *D) {
   if (D && !D->isDynamic()) {
+    assert(!D->isFinal());
     D->getAttrs().add(new (ctx) DynamicAttr(/*IsImplicit=*/true));
   }
 }
@@ -2556,15 +2558,29 @@ static void inferDynamic(ASTContext &ctx, ValueDecl *D) {
 
   // Variables declared with 'let' cannot be 'dynamic'.
   if (auto VD = dyn_cast<VarDecl>(D)) {
-    if (VD->isLet() && !isNSManaged) return;
+    auto staticSpelling = VD->getParentPatternBinding()->getStaticSpelling();
+
+    // The presence of 'static' bocks the inference of 'dynamic'.
+    if (VD->isStatic() && staticSpelling == StaticSpellingKind::KeywordStatic)
+      return;
+
+    if (VD->isLet() && !isNSManaged)
+      return;
   }
 
   // Accessors should not infer 'dynamic' on their own; they can get it from
   // their storage decls.
-  if (auto FD = dyn_cast<FuncDecl>(D))
+  if (auto FD = dyn_cast<FuncDecl>(D)) {
     if (FD->isAccessor())
       return;
 
+    auto staticSpelling = FD->getStaticSpelling();
+
+    // The presence of 'static' bocks the inference of 'dynamic'.
+    if (FD->isStatic() && staticSpelling == StaticSpellingKind::KeywordStatic)
+      return;
+  }
+
   // The presence of 'final' on a class prevents 'dynamic'.
   auto classDecl = D->getDeclContext()->getAsClassOrClassExtensionContext();
   if (!classDecl) return;
@@ -5176,8 +5192,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
         // If the storage is dynamic or final, propagate to this accessor.
         if (isObjC &&
-            storage->isDynamic() &&
-            !storage->isFinal())
+            storage->isDynamic())
           makeDynamic(TC.Context, FD);
 
         if (storage->isFinal())
diff --git a/test/attr/attr_dynamic_infer.swift b/test/attr/attr_dynamic_infer.swift
index 4fc57ba3cf35a..f81765e04ec8f 100644
--- a/test/attr/attr_dynamic_infer.swift
+++ b/test/attr/attr_dynamic_infer.swift
@@ -59,7 +59,7 @@ extension Sub {
 @objc class FinalTests {}
 
 extension FinalTests {
-  // CHECK:  @objc final func foo
+  // CHECK: @objc final func foo
   final func foo() { }
 
   // CHECK: @objc final var prop: Super
@@ -77,5 +77,11 @@ extension FinalTests {
     // CHECK: @objc final set
     set { }
   }
+
+  // CHECK: static @objc var x
+  static var x: Int = 0
+
+  // CHECK: @objc static func bar
+  static func bar() { }
 }