[CodeCompletion] Make sawSolution non-final and override sawSolutionImpl from subclasses

This eliminates a source of bugs if subclasses of `TypeCheckCompletionCallback` forget to call the superclass’s implementation of `sawSolution` from their overridden method.

Author: ahoppen

include/swift/IDE/ArgumentCompletion.h

@@ -63,13 +63,13 @@ class ArgumentTypeCheckCompletionCallback : public TypeCheckCompletionCallback {
                          SmallVectorImpl<PossibleParamInfo> &Params,
                          SmallVectorImpl<Type> &Types);
 
+  void sawSolutionImpl(const constraints::Solution &solution) override;
+
 public:
   ArgumentTypeCheckCompletionCallback(CodeCompletionExpr *CompletionExpr,
                                       DeclContext *DC)
       : CompletionExpr(CompletionExpr), DC(DC) {}
 
-  void sawSolution(const constraints::Solution &solution) override;
-
   /// \param IncludeSignature Whether to include a suggestion for the entire
   /// function signature instead of suggesting individual labels. Used when
   /// completing after the opening '(' of a function call \param Loc The

include/swift/IDE/DotExprCompletion.h

@@ -43,6 +43,8 @@ class DotExprTypeCheckCompletionCallback : public TypeCheckCompletionCallback {
   SmallVector<Result, 4> Results;
   llvm::DenseMap<std::pair<Type, Decl *>, size_t> BaseToSolutionIdx;
 
+  void sawSolutionImpl(const constraints::Solution &solution) override;
+
 public:
   DotExprTypeCheckCompletionCallback(CodeCompletionExpr *CompletionExpr,
                                      DeclContext *DC)
@@ -52,8 +54,6 @@ class DotExprTypeCheckCompletionCallback : public TypeCheckCompletionCallback {
   /// \c sawSolution for each solution formed.
   void fallbackTypeCheck(DeclContext *DC) override;
 
-  void sawSolution(const constraints::Solution &solution) override;
-
   void deliverResults(Expr *BaseExpr, DeclContext *DC, SourceLoc DotLoc,
                       bool IsInSelector, CodeCompletionContext &CompletionCtx,
                       CodeCompletionConsumer &Consumer);

include/swift/IDE/ExprCompletion.h

@@ -46,14 +46,14 @@ class ExprTypeCheckCompletionCallback : public TypeCheckCompletionCallback {
 
   SmallVector<Result, 4> Results;
 
+  void sawSolutionImpl(const constraints::Solution &solution) override;
+
 public:
   /// \param DC The decl context in which the \p CompletionExpr occurs.
   ExprTypeCheckCompletionCallback(CodeCompletionExpr *CompletionExpr,
                                   DeclContext *DC)
       : CompletionExpr(CompletionExpr), DC(DC) {}
 
-  void sawSolution(const constraints::Solution &solution) override;
-
   /// \param CCLoc The location of the code completion token.
   void deliverResults(SourceLoc CCLoc,
                       ide::CodeCompletionContext &CompletionCtx,

include/swift/IDE/KeyPathCompletion.h

@@ -32,11 +32,11 @@ class KeyPathTypeCheckCompletionCallback : public TypeCheckCompletionCallback {
   KeyPathExpr *KeyPath;
   SmallVector<Result, 4> Results;
 
+  void sawSolutionImpl(const constraints::Solution &solution) override;
+
 public:
   KeyPathTypeCheckCompletionCallback(KeyPathExpr *KeyPath) : KeyPath(KeyPath) {}
 
-  void sawSolution(const constraints::Solution &solution) override;
-
   void deliverResults(DeclContext *DC, SourceLoc DotLoc,
                       ide::CodeCompletionContext &CompletionCtx,
                       CodeCompletionConsumer &Consumer);

include/swift/IDE/TypeCheckCompletionCallback.h

@@ -41,13 +41,19 @@ namespace ide {
 class TypeCheckCompletionCallback {
   bool GotCallback = false;
 
+protected:
+  /// Subclasses of \c TypeCheckCompletionCallback handle solutions discovered
+  /// by the constraint system in this function
+  virtual void sawSolutionImpl(const constraints::Solution &solution) = 0;
+
 public:
   virtual ~TypeCheckCompletionCallback() {}
 
   /// Called for each solution produced while type-checking an expression
   /// that the code completion expression participates in.
-  virtual void sawSolution(const constraints::Solution &solution) {
+  void sawSolution(const constraints::Solution &solution) {
     GotCallback = true;
+    sawSolutionImpl(solution);
   };
 
   /// True if at least one solution was passed via the \c sawSolution

include/swift/IDE/UnresolvedMemberCompletion.h

@@ -40,13 +40,13 @@ class UnresolvedMemberTypeCheckCompletionCallback
   SmallVector<Result, 4> ExprResults;
   SmallVector<Result, 1> EnumPatternTypes;
 
+  void sawSolutionImpl(const constraints::Solution &solution) override;
+
 public:
   UnresolvedMemberTypeCheckCompletionCallback(
       CodeCompletionExpr *CompletionExpr, DeclContext *DC)
       : CompletionExpr(CompletionExpr), DC(DC) {}
 
-  void sawSolution(const constraints::Solution &solution) override;
-
   void deliverResults(DeclContext *DC, SourceLoc DotLoc,
                       ide::CodeCompletionContext &CompletionCtx,
                       CodeCompletionConsumer &Consumer);

lib/IDE/ArgumentCompletion.cpp

@@ -90,9 +90,7 @@ bool ArgumentTypeCheckCompletionCallback::addPossibleParams(
   return ShowGlobalCompletions;
 }
 
-void ArgumentTypeCheckCompletionCallback::sawSolution(const Solution &S) {
-  TypeCheckCompletionCallback::sawSolution(S);
-
+void ArgumentTypeCheckCompletionCallback::sawSolutionImpl(const Solution &S) {
   Type ExpectedTy = getTypeForCompletion(S, CompletionExpr);
 
   auto &CS = S.getConstraintSystem();

lib/IDE/DotExprCompletion.cpp

@@ -44,9 +44,8 @@ void DotExprTypeCheckCompletionCallback::fallbackTypeCheck(DeclContext *DC) {
                              [&](const Solution &S) { sawSolution(S); });
 }
 
-void DotExprTypeCheckCompletionCallback::sawSolution(
+void DotExprTypeCheckCompletionCallback::sawSolutionImpl(
     const constraints::Solution &S) {
-  TypeCheckCompletionCallback::sawSolution(S);
   auto &CS = S.getConstraintSystem();
   auto *ParsedExpr = CompletionExpr->getBase();
   auto *SemanticExpr = ParsedExpr->getSemanticsProvidingExpr();

lib/IDE/ExprCompletion.cpp

@@ -19,10 +19,8 @@ using namespace swift;
 using namespace swift::ide;
 using namespace swift::constraints;
 
-void ExprTypeCheckCompletionCallback::sawSolution(
+void ExprTypeCheckCompletionCallback::sawSolutionImpl(
     const constraints::Solution &S) {
-  TypeCheckCompletionCallback::sawSolution(S);
-
   auto &CS = S.getConstraintSystem();
 
   Type ExpectedTy = getTypeForCompletion(S, CompletionExpr);

lib/IDE/KeyPathCompletion.cpp

@@ -19,10 +19,8 @@ using namespace swift;
 using namespace swift::constraints;
 using namespace swift::ide;
 
-void KeyPathTypeCheckCompletionCallback::sawSolution(
+void KeyPathTypeCheckCompletionCallback::sawSolutionImpl(
     const constraints::Solution &S) {
-  TypeCheckCompletionCallback::sawSolution(S);
-
   // Determine the code completion.
   size_t ComponentIndex = 0;
   for (auto &Component : KeyPath->getComponents()) {