[ModuleInterface] Allow global/static variables without initial values

Author: jrose-apple

lib/Sema/TypeCheckDecl.cpp

@@ -2520,45 +2520,61 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
         if (!var->hasStorage())
           return;
 
+        if (var->isInvalid() || PBD->isInvalid())
+          return;
+
         auto *varDC = var->getDeclContext();
 
-        // Non-member observing properties need an initializer.
-        if (var->getWriteImpl() == WriteImplKind::StoredWithObservers &&
-            !isTypeContext && !var->isInvalid() && !PBD->isInvalid()) {
-          TC.diagnose(var->getLoc(), diag::observingprop_requires_initializer);
+        auto markVarAndPBDInvalid = [PBD, var] {
           PBD->setInvalid();
           var->setInvalid();
-          if (!var->hasType()) {
+          if (!var->hasType())
             var->markInvalid();
-          }
+        };
+
+        // Non-member observing properties need an initializer.
+        if (var->getWriteImpl() == WriteImplKind::StoredWithObservers &&
+            !isTypeContext) {
+          TC.diagnose(var->getLoc(), diag::observingprop_requires_initializer);
+          markVarAndPBDInvalid();
           return;
         }
 
         // Static/class declarations require an initializer unless in a
         // protocol.
-        if (var->isStatic() && !isa<ProtocolDecl>(varDC) &&
-            !var->isInvalid() && !PBD->isInvalid()) {
+        if (var->isStatic() && !isa<ProtocolDecl>(varDC)) {
+          // ...but don't enforce this for SIL or textual interface files.
+          switch (varDC->getParentSourceFile()->Kind) {
+          case SourceFileKind::Interface:
+          case SourceFileKind::SIL:
+            return;
+          case SourceFileKind::Main:
+          case SourceFileKind::REPL:
+          case SourceFileKind::Library:
+            break;
+          }
+
           TC.diagnose(var->getLoc(), diag::static_requires_initializer,
                       var->getCorrectStaticSpelling());
-          PBD->setInvalid();
-          var->setInvalid();
-          if (!var->hasType()) {
-            var->markInvalid();
-          }
+          markVarAndPBDInvalid();
           return;
         }
 
-        // Global variables require an initializer (except in top level code).
-        if (varDC->isModuleScopeContext() &&
-            !varDC->getParentSourceFile()->isScriptMode() &&
-            !var->isInvalid() && !PBD->isInvalid()) {
-          TC.diagnose(var->getLoc(),
-                      diag::global_requires_initializer, var->isLet());
-          PBD->setInvalid();
-          var->setInvalid();
-          if (!var->hasType()) {
-            var->markInvalid();
+        // Global variables require an initializer in normal source files.
+        if (varDC->isModuleScopeContext()) {
+          switch (varDC->getParentSourceFile()->Kind) {
+          case SourceFileKind::Main:
+          case SourceFileKind::REPL:
+          case SourceFileKind::Interface:
+          case SourceFileKind::SIL:
+            return;
+          case SourceFileKind::Library:
+            break;
           }
+
+          TC.diagnose(var->getLoc(), diag::global_requires_initializer,
+                      var->isLet());
+          markVarAndPBDInvalid();
           return;
         }
       });

test/ModuleInterface/SmokeTest.swiftinterface

@@ -22,6 +22,9 @@ public class TestClass {
   // CHECK: public var prop: Int{{$}}
   public var prop: Int { get set }
 
+  // CHECK: public static var propWithNoAccessors: Int{{$}}
+  public static var propWithNoAccessors: Int
+
   // NEGATIVE-NOT: deinit
   deinit
 } // CHECK: {{^}$}}
@@ -42,6 +45,9 @@ public enum TestEnum {
 
   // CHECK: public var prop: Int{{$}}
   public var prop: Int { get set }
+
+  // CHECK: public static var propWithNoAccessors: Int{{$}}
+  public static var propWithNoAccessors: Int
 } // CHECK: {{^}$}}
 
 // CHECK-LABEL: public struct TestStruct
@@ -57,8 +63,14 @@ public struct TestStruct {
 
   // CHECK: public var prop: Int{{$}}
   public var prop: Int { get set }
+
+  // CHECK: public static var propWithNoAccessors: Int{{$}}
+  public static var propWithNoAccessors: Int
 } // CHECK: {{^}$}}
 
+// CHECK: public let globalWithNoAccessors: Int{{$}}
+public let globalWithNoAccessors: Int
+
 // CHECK: public var readOnlyVar: Int { get }{{$}}
 public var readOnlyVar: Int { get }