Merge pull request swiftlang#25877 from slavapestov/dynamic-self-stored-property-init-diagnostic

Diagnose usages of 'Self' in stored property initializers

Author: slavapestov

include/swift/AST/AnyFunctionRef.h

@@ -52,12 +52,20 @@ class AnyFunctionRef {
     }
   }
 
-  CaptureInfo &getCaptureInfo() const {
+  const CaptureInfo &getCaptureInfo() const {
     if (auto *AFD = TheFunction.dyn_cast<AbstractFunctionDecl *>())
       return AFD->getCaptureInfo();
     return TheFunction.get<AbstractClosureExpr *>()->getCaptureInfo();
   }
 
+  void setCaptureInfo(const CaptureInfo &captures) const {
+    if (auto *AFD = TheFunction.dyn_cast<AbstractFunctionDecl *>()) {
+      AFD->setCaptureInfo(captures);
+      return;
+    }
+    TheFunction.get<AbstractClosureExpr *>()->setCaptureInfo(captures);
+  }
+
   void getLocalCaptures(SmallVectorImpl<CapturedValue> &Result) const {
     getCaptureInfo().getLocalCaptures(Result);
   }

include/swift/AST/CaptureInfo.h

@@ -126,9 +126,9 @@ class CaptureInfo {
     : Captures(nullptr), DynamicSelf(nullptr), OpaqueValue(nullptr), Count(0),
       GenericParamCaptures(0), Computed(0) { }
 
-  bool hasBeenComputed() { return Computed; }
+  bool hasBeenComputed() const { return Computed; }
 
-  bool isTrivial() {
+  bool isTrivial() const {
     return Count == 0 && !GenericParamCaptures && !DynamicSelf && !OpaqueValue;
   }
 

include/swift/AST/Decl.h

@@ -1932,6 +1932,9 @@ class PatternBindingEntry {
   /// The initializer context used for this pattern binding entry.
   llvm::PointerIntPair<DeclContext *, 1, bool> InitContextAndIsText;
 
+  /// Values captured by this initializer.
+  CaptureInfo Captures;
+
   friend class PatternBindingInitializer;
 
 public:
@@ -2025,6 +2028,9 @@ class PatternBindingEntry {
   /// \param omitAccessors Whether the computation should omit the accessors
   /// from the source range.
   SourceRange getSourceRange(bool omitAccessors = false) const;
+
+  const CaptureInfo &getCaptureInfo() const { return Captures; }
+  void setCaptureInfo(const CaptureInfo &captures) { Captures = captures; }
 };
 
 /// This decl contains a pattern and optional initializer for a set
@@ -2122,6 +2128,18 @@ class PatternBindingDecl final : public Decl,
 
   void setPattern(unsigned i, Pattern *Pat, DeclContext *InitContext);
 
+  DeclContext *getInitContext(unsigned i) const {
+    return getPatternList()[i].getInitContext();
+  }
+
+  const CaptureInfo &getCaptureInfo(unsigned i) const {
+    return getPatternList()[i].getCaptureInfo();
+  }
+
+  void setCaptureInfo(unsigned i, const CaptureInfo &captures) {
+    getMutablePatternList()[i].setCaptureInfo(captures);
+  }
+
   /// Given that this PBD is the parent pattern for the specified VarDecl,
   /// return the entry of the VarDecl in our PatternList.  For example, in:
   ///
@@ -5847,8 +5865,8 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
   /// Retrieve the source range of the function declaration name + patterns.
   SourceRange getSignatureSourceRange() const;
 
-  CaptureInfo &getCaptureInfo() { return Captures; }
   const CaptureInfo &getCaptureInfo() const { return Captures; }
+  void setCaptureInfo(const CaptureInfo &captures) { Captures = captures; }
 
   /// Retrieve the Objective-C selector that names this method.
   ObjCSelector getObjCSelector(DeclName preferredName = DeclName(),

include/swift/AST/DiagnosticsSema.def

@@ -2595,6 +2595,8 @@ ERROR(dynamic_self_invalid_subscript,none,
       "covariant 'Self' can only appear at the top level of subscript element type", ())
 ERROR(dynamic_self_invalid_method,none,
       "covariant 'Self' can only appear at the top level of method result type", ())
+ERROR(dynamic_self_stored_property_init,none,
+      "covariant 'Self' type cannot be referenced from a stored property initializer", ())
 
 //------------------------------------------------------------------------------
 // MARK: Type Check Attributes

include/swift/AST/Expr.h

@@ -3427,8 +3427,8 @@ class AbstractClosureExpr : public DeclContext, public Expr {
     Bits.AbstractClosureExpr.Discriminator = Discriminator;
   }
 
-  CaptureInfo &getCaptureInfo() { return Captures; }
   const CaptureInfo &getCaptureInfo() const { return Captures; }
+  void setCaptureInfo(CaptureInfo captures) { Captures = captures; }
 
   /// Retrieve the parameters of this closure.
   ParameterList *getParameters() { return parameterList; }

lib/SILGen/SILGen.cpp

@@ -1132,6 +1132,7 @@ emitStoredPropertyInitialization(PatternBindingDecl *pbd, unsigned i) {
   auto *var = pbdEntry.getAnchoringVarDecl();
   auto *init = pbdEntry.getInit();
   auto *initDC = pbdEntry.getInitContext();
+  auto &captureInfo = pbdEntry.getCaptureInfo();
   assert(!pbdEntry.isInitializerSubsumed());
 
   // If this is the backing storage for a property with an attached wrapper
@@ -1148,12 +1149,23 @@ emitStoredPropertyInitialization(PatternBindingDecl *pbd, unsigned i) {
 
   SILDeclRef constant(var, SILDeclRef::Kind::StoredPropertyInitializer);
   emitOrDelayFunction(*this, constant,
-                      [this,constant,init,initDC](SILFunction *f) {
+                      [this,var,captureInfo,constant,init,initDC](SILFunction *f) {
     preEmitFunction(constant, init, f, init);
     PrettyStackTraceSILFunction X("silgen emitStoredPropertyInitialization", f);
     f->createProfiler(init, constant, ForDefinition);
-    SILGenFunction(*this, *f, initDC)
-        .emitGeneratorFunction(constant, init, /*EmitProfilerIncrement=*/true);
+    SILGenFunction SGF(*this, *f, initDC);
+
+    // If this is a stored property initializer inside a type at global scope,
+    // it may close over a global variable. If we're emitting top-level code,
+    // then emit a "mark_function_escape" that lists the captured global
+    // variables so that definite initialization can reason about this
+    // escape point.
+    if (!var->getDeclContext()->isLocalContext() &&
+        TopLevelSGF && TopLevelSGF->B.hasValidInsertionPoint()) {
+      emitMarkFunctionEscapeForTopLevelCodeGlobals(var, captureInfo);
+    }
+
+    SGF.emitGeneratorFunction(constant, init, /*EmitProfilerIncrement=*/true);
     postEmitFunction(constant, f);
   });
 }