[AST] Split up PatternBindingDecl::setPattern

Most clients only want to set one of the two
parameters, split it into `setPattern` and
`setInitContext` (the latter of which now
handles calling `setBinding`).

Author: hamishknight

include/swift/AST/Decl.h

@@ -2318,9 +2318,7 @@ class PatternBindingDecl final : public Decl,
     return getPatternList()[i].getPattern();
   }
 
-  void setPattern(unsigned i, Pattern *Pat,
-                  PatternBindingInitializer *InitContext,
-                  bool isFullyValidated = false);
+  void setPattern(unsigned i, Pattern *P, bool isFullyValidated = false);
 
   bool isFullyValidated(unsigned i) const {
     return getPatternList()[i].isFullyValidated();
@@ -2330,6 +2328,13 @@ class PatternBindingDecl final : public Decl,
     return getPatternList()[i].getInitContext();
   }
 
+  void setInitContext(unsigned i, PatternBindingInitializer *init) {
+    if (init) {
+      init->setBinding(this, i);
+    }
+    getMutablePatternList()[i].setInitContext(init);
+  }
+
   CaptureInfo getCaptureInfo(unsigned i) const {
     return getPatternList()[i].getCaptureInfo();
   }

lib/AST/ASTWalker.cpp

@@ -202,7 +202,7 @@ class Traversal : public ASTVisitor<Traversal, Expr*, Stmt*,
 
     for (auto idx : range(PBD->getNumPatternEntries())) {
       if (Pattern *Pat = doIt(PBD->getPattern(idx)))
-        PBD->setPattern(idx, Pat, PBD->getInitContext(idx));
+        PBD->setPattern(idx, Pat);
       else
         return true;
 

lib/AST/Decl.cpp

@@ -1932,12 +1932,11 @@ PatternBindingDecl::create(ASTContext &Ctx, SourceLoc StaticLoc,
     if (!initContext && !Parent->isLocalContext())
       initContext = PatternBindingInitializer::create(Parent);
 
-    if (initContext)
-      initContext->setBinding(PBD, idx);
-
     // We need to call setPattern to ensure the VarDecls in the pattern have
-    // the PatternBindingDecl set as their parent, and to setup the context.
-    PBD->setPattern(idx, PBD->getPattern(idx), initContext);
+    // the PatternBindingDecl set as their parent. We also need to call
+    // setInitContext to setup the context.
+    PBD->setPattern(idx, PBD->getPattern(idx));
+    PBD->setInitContext(idx, initContext);
   }
   return PBD;
 }
@@ -2238,12 +2237,10 @@ PatternBindingDecl::getCheckedPatternBindingEntry(unsigned i) const {
 }
 
 void PatternBindingDecl::setPattern(unsigned i, Pattern *P,
-                                    PatternBindingInitializer *InitContext,
                                     bool isFullyValidated) {
   auto PatternList = getMutablePatternList();
   PatternList[i].setPattern(P);
-  PatternList[i].setInitContext(InitContext);
-  
+
   // Make sure that any VarDecl's contained within the pattern know about this
   // PatternBindingDecl as their parent.
   if (P) {

lib/Sema/CSApply.cpp

@@ -9525,7 +9525,6 @@ ExprWalker::rewriteTarget(SyntacticElementTarget target) {
       // this is important for subsequent call to typeCheckDecl
       // because otherwise it would try to re-typecheck pattern.
       patternBinding->setPattern(index, pattern,
-                                 patternBinding->getInitContext(index),
                                  /*isFullyValidated=*/true);
 
       if (patternBinding->isExplicitlyInitialized(index) ||

lib/Sema/CSGen.cpp

@@ -4838,8 +4838,7 @@ bool ConstraintSystem::generateConstraints(
 
       // Reset binding to point to the resolved pattern. This is required
       // before calling `forPatternBindingDecl`.
-      patternBinding->setPattern(index, pattern,
-                                 patternBinding->getInitContext(index));
+      patternBinding->setPattern(index, pattern);
 
       auto contextualPattern =
           ContextualPattern::forPatternBindingDecl(patternBinding, index);

lib/Sema/CSSyntacticElement.cpp

@@ -715,8 +715,7 @@ class SyntacticElementConstraintGenerator
 
       // Reset binding to point to the resolved pattern. This is required
       // before calling `forPatternBindingDecl`.
-      patternBinding->setPattern(index, pattern,
-                                 patternBinding->getInitContext(index));
+      patternBinding->setPattern(index, pattern);
 
       patterns.push_back(makeElement(
           patternBinding,

lib/Sema/TypeCheckConstraints.cpp

@@ -880,7 +880,7 @@ bool TypeChecker::typeCheckPatternBinding(PatternBindingDecl *PBD,
     return true;
   }
 
-  PBD->setPattern(patternNumber, pattern, initContext);
+  PBD->setPattern(patternNumber, pattern);
   PBD->setInit(patternNumber, init);
 
   if (hadError)

lib/Sema/TypeCheckStorage.cpp

@@ -411,8 +411,7 @@ const PatternBindingEntry *PatternBindingEntryRequest::evaluate(
     return &pbe;
   }
 
-  binding->setPattern(entryNumber, pattern,
-                      binding->getInitContext(entryNumber));
+  binding->setPattern(entryNumber, pattern);
 
   // Validate 'static'/'class' on properties in nominal type decls.
   auto StaticSpelling = binding->getStaticSpelling();

lib/Serialization/Deserialization.cpp

@@ -4360,9 +4360,9 @@ class DeclDeserializer {
       binding->setImplicit();
 
     for (unsigned i = 0; i != patterns.size(); ++i) {
-      DeclContext *initContext = MF.getDeclContext(patterns[i].second);
-      binding->setPattern(i, patterns[i].first,
-                          cast_or_null<PatternBindingInitializer>(initContext));
+      binding->setPattern(i, patterns[i].first);
+      if (auto *context = MF.getDeclContext(patterns[i].second))
+        binding->setInitContext(i, cast<PatternBindingInitializer>(context));
     }
 
     return binding;