Start hiding the interface to PatternBindingEntry

Force callers to go through the pattern binding decl so we can control the API surface more effectively.

Author: CodaFi

include/swift/AST/Decl.h

@@ -1930,7 +1930,9 @@ class PatternBindingEntry {
   CaptureInfo Captures;
 
   friend class PatternBindingInitializer;
+  friend class PatternBindingDecl;
 
+private:
   // FIXME: This API is transitional. Once the callers of
   // typeCheckPatternBinding are requestified, merge this bit with
   // Flags::Checked.
@@ -1952,6 +1954,7 @@ class PatternBindingEntry {
       : PatternAndFlags(P, {}), InitExpr({E, E, EqualLoc}),
         InitContextAndFlags({InitContext, None}) {}
 
+private:
   Pattern *getPattern() const { return PatternAndFlags.getPointer(); }
   void setPattern(Pattern *P) { PatternAndFlags.setPointer(P); }
 
@@ -2210,7 +2213,12 @@ class PatternBindingDecl final : public Decl,
 
   /// Can the pattern at index i be default initialized?
   bool isDefaultInitializable(unsigned i) const;
-  
+
+  /// Does this pattern have a user-provided initializer expression?
+  bool isExplicitlyInitialized(unsigned i) const;
+
+  SourceLoc getEqualLoc(unsigned i) const;
+
   /// When the pattern binding contains only a single variable with no
   /// destructuring, retrieve that variable.
   VarDecl *getSingleVar() const;
@@ -4981,15 +4989,19 @@ class VarDecl : public AbstractStorageDecl {
   /// binding has no initial value, this returns null.
   ///
   Expr *getParentInitializer() const {
-    if (auto *PBD = getParentPatternBinding())
-      return PBD->getPatternEntryForVarDecl(this).getInit();
+    if (auto *PBD = getParentPatternBinding()) {
+      const auto i = PBD->getPatternEntryIndexForVarDecl(this);
+      return PBD->getInit(i);
+    }
     return nullptr;
   }
 
   /// Whether there exists an initializer for this \c VarDecl.
   bool isParentInitialized() const {
-    if (auto *PBD = getParentPatternBinding())
-      return PBD->getPatternEntryForVarDecl(this).isInitialized();
+    if (auto *PBD = getParentPatternBinding()) {
+      const auto i = PBD->getPatternEntryIndexForVarDecl(this);
+      return PBD->isInitialized(i);
+    }
     return false;
   }
 

lib/AST/Decl.cpp

@@ -1735,13 +1735,24 @@ bool PatternBindingDecl::isDefaultInitializable(unsigned i) const {
   return false;
 }
 
+
 bool PatternBindingDecl::isComputingPatternBindingEntry(
     const VarDecl *vd) const {
   unsigned i = getPatternEntryIndexForVarDecl(vd);
   return getASTContext().evaluator.hasActiveRequest(
       PatternBindingEntryRequest{const_cast<PatternBindingDecl *>(this), i});
 }
 
+bool PatternBindingDecl::isExplicitlyInitialized(unsigned i) const {
+  const auto entry = getPatternList()[i];
+  return entry.isInitialized() && entry.getEqualLoc().isValid();
+}
+
+SourceLoc getEqualLoc(unsigned i) const {
+  const auto entry = getPatternList()[i];
+  return entry.getEqualLoc(i);
+}
+
 SourceLoc TopLevelCodeDecl::getStartLoc() const {
   return Body->getStartLoc();
 }
@@ -5282,9 +5293,11 @@ Stmt *VarDecl::getRecursiveParentPatternStmt() const {
 ///
 Pattern *VarDecl::getParentPattern() const {
   // If this has a PatternBindingDecl parent, use its pattern.
-  if (auto *PBD = getParentPatternBinding())
-    return PBD->getPatternEntryForVarDecl(this).getPattern();
-  
+  if (auto *PBD = getParentPatternBinding()) {
+    const auto i = PBD->getPatternEntryIndexForVarDecl(this);
+    return PBD->getPattern(i);
+  }
+
   // If this is a statement parent, dig the pattern out of it.
   if (auto *stmt = getParentPatternStmt()) {
     if (auto *FES = dyn_cast<ForEachStmt>(stmt))
@@ -5925,8 +5938,7 @@ Expr *swift::findOriginalPropertyWrapperInitialValue(VarDecl *var,
     return nullptr;
 
   // If there is no '=' on the pattern, there was no initial value.
-  if (PBD->getPatternList()[0].getEqualLoc().isInvalid()
-      && !PBD->isDefaultInitializable())
+  if (PBD->getEqualLoc(0).isInvalid() && !PBD->isDefaultInitializable())
     return nullptr;
 
   ASTContext &ctx = var->getASTContext();