Sema: Move SimpleDidSetRequest::evaluate() to TypeCheckStorage.cpp

I think TypeCheckStorage.cpp is a better place for this than
TypeCheckDecl.cpp, since all the other requests for storage
and accessor declarations appear in the former.

Author: slavapestov

lib/Sema/TypeCheckDecl.cpp

@@ -1273,73 +1273,6 @@ EnumRawValuesRequest::evaluate(Evaluator &eval, EnumDecl *ED,
   return std::make_tuple<>();
 }
 
-bool SimpleDidSetRequest::evaluate(Evaluator &evaluator,
-                                   AccessorDecl *decl) const {
-
-  class OldValueFinder : public ASTWalker {
-    const ParamDecl *OldValueParam;
-    bool foundOldValueRef = false;
-
-  public:
-    OldValueFinder(const ParamDecl *param) : OldValueParam(param) {}
-
-    virtual std::pair<bool, Expr *> walkToExprPre(Expr *E) override {
-      if (!E)
-        return {true, E};
-      if (auto DRE = dyn_cast<DeclRefExpr>(E)) {
-        if (auto decl = DRE->getDecl()) {
-          if (decl == OldValueParam) {
-            foundOldValueRef = true;
-            return {false, nullptr};
-          }
-        }
-      }
-
-      return {true, E};
-    }
-
-    bool didFindOldValueRef() { return foundOldValueRef; }
-  };
-
-  // If this is not a didSet accessor, bail out.
-  if (decl->getAccessorKind() != AccessorKind::DidSet) {
-    return false;
-  }
-
-  // Always assume non-simple 'didSet' in code completion mode.
-  if (decl->getASTContext().SourceMgr.hasCodeCompletionBuffer())
-    return false;
-
-  // didSet must have a single parameter.
-  if (decl->getParameters()->size() != 1) {
-    return false;
-  }
-
-  auto param = decl->getParameters()->get(0);
-  // If this parameter is not implicit, then it means it has been explicitly
-  // provided by the user (i.e. 'didSet(oldValue)'). This means we cannot
-  // consider this a "simple" didSet because we have to fetch the oldValue
-  // regardless of whether it's referenced in the body or not.
-  if (!param->isImplicit()) {
-    return false;
-  }
-
-  // If we find a reference to the implicit 'oldValue' parameter, then it is
-  // not a "simple" didSet because we need to fetch it.
-  auto walker = OldValueFinder(param);
-  decl->getTypecheckedBody()->walk(walker);
-  auto hasOldValueRef = walker.didFindOldValueRef();
-  if (!hasOldValueRef) {
-    // If the body does not refer to implicit 'oldValue', it means we can
-    // consider this as a "simple" didSet. Let's also erase the implicit
-    // oldValue as it is never used.
-    auto &ctx = decl->getASTContext();
-    decl->setParameters(ParameterList::createEmpty(ctx));
-    return true;
-  }
-  return false;
-}
-
 const ConstructorDecl *
 swift::findNonImplicitRequiredInit(const ConstructorDecl *CD) {
   while (CD->isImplicit()) {

lib/Sema/TypeCheckStorage.cpp

@@ -3186,3 +3186,71 @@ StorageImplInfoRequest::evaluate(Evaluator &evaluator,
 
   return info;
 }
+
+bool SimpleDidSetRequest::evaluate(Evaluator &evaluator,
+                                   AccessorDecl *decl) const {
+
+  class OldValueFinder : public ASTWalker {
+    const ParamDecl *OldValueParam;
+    bool foundOldValueRef = false;
+
+  public:
+    OldValueFinder(const ParamDecl *param) : OldValueParam(param) {}
+
+    virtual std::pair<bool, Expr *> walkToExprPre(Expr *E) override {
+      if (!E)
+        return {true, E};
+      if (auto DRE = dyn_cast<DeclRefExpr>(E)) {
+        if (auto decl = DRE->getDecl()) {
+          if (decl == OldValueParam) {
+            foundOldValueRef = true;
+            return {false, nullptr};
+          }
+        }
+      }
+
+      return {true, E};
+    }
+
+    bool didFindOldValueRef() { return foundOldValueRef; }
+  };
+
+  // If this is not a didSet accessor, bail out.
+  if (decl->getAccessorKind() != AccessorKind::DidSet) {
+    return false;
+  }
+
+  // Always assume non-simple 'didSet' in code completion mode.
+  if (decl->getASTContext().SourceMgr.hasCodeCompletionBuffer())
+    return false;
+
+  // didSet must have a single parameter.
+  if (decl->getParameters()->size() != 1) {
+    return false;
+  }
+
+  auto param = decl->getParameters()->get(0);
+  // If this parameter is not implicit, then it means it has been explicitly
+  // provided by the user (i.e. 'didSet(oldValue)'). This means we cannot
+  // consider this a "simple" didSet because we have to fetch the oldValue
+  // regardless of whether it's referenced in the body or not.
+  if (!param->isImplicit()) {
+    return false;
+  }
+
+  // If we find a reference to the implicit 'oldValue' parameter, then it is
+  // not a "simple" didSet because we need to fetch it.
+  auto walker = OldValueFinder(param);
+  decl->getTypecheckedBody()->walk(walker);
+  auto hasOldValueRef = walker.didFindOldValueRef();
+  if (!hasOldValueRef) {
+    // If the body does not refer to implicit 'oldValue', it means we can
+    // consider this as a "simple" didSet. Let's also erase the implicit
+    // oldValue as it is never used.
+    auto &ctx = decl->getASTContext();
+    decl->setParameters(ParameterList::createEmpty(ctx));
+    return true;
+  }
+  return false;
+}
+