[CodeCompletion] Unify logic to retrieve completion expr type for all completion callbacks

Author: ahoppen

lib/IDE/ArgumentCompletion.cpp

@@ -94,9 +94,6 @@ void ArgumentTypeCheckCompletionCallback::sawSolution(const Solution &S) {
   TypeCheckCompletionCallback::sawSolution(S);
 
   Type ExpectedTy = getTypeForCompletion(S, CompletionExpr);
-  if (!ExpectedTy) {
-    return;
-  }
 
   auto &CS = S.getConstraintSystem();
 

lib/IDE/DotExprCompletion.cpp

@@ -55,7 +55,7 @@ void DotExprTypeCheckCompletionCallback::sawSolution(
   // If base type couldn't be determined (e.g. because base expression
   // is an invalid reference), let's not attempt to do a lookup since
   // it wouldn't produce any useful results anyway.
-  if (!BaseTy || BaseTy->getRValueType()->is<UnresolvedType>())
+  if (!BaseTy)
     return;
 
   auto *Locator = CS.getConstraintLocator(SemanticExpr);

lib/IDE/ExprCompletion.cpp

@@ -25,18 +25,7 @@ void ExprTypeCheckCompletionCallback::sawSolution(
 
   auto &CS = S.getConstraintSystem();
 
-  // Prefer to get the expected type as the completion expression's contextual
-  // type. If that fails (because there is no explicit contextual type spelled
-  // out in the source), the code completion expression will have been
-  // type-checked to its expected contextual type.
-  Type ExpectedTy =
-      CS.getContextualType(CompletionExpr, /*forConstraint=*/false);
-  if (!ExpectedTy) {
-    ExpectedTy = S.getResolvedType(CompletionExpr);
-  }
-  if (ExpectedTy->hasUnresolvedType()) {
-    ExpectedTy = Type();
-  }
+  Type ExpectedTy = getTypeForCompletion(S, CompletionExpr);
 
   bool ImplicitReturn = isImplicitSingleExpressionReturn(CS, CompletionExpr);
 

lib/IDE/TypeCheckCompletionCallback.cpp

@@ -47,6 +47,8 @@ Type swift::ide::getTypeForCompletion(const constraints::Solution &S, Expr *E) {
 
   auto &CS = S.getConstraintSystem();
 
+  Type Result;
+
   // To aid code completion, we need to attempt to convert type placeholders
   // back into underlying generic parameters if possible, since type
   // of the code completion expression is used as "expected" (or contextual)
@@ -70,7 +72,7 @@ Type swift::ide::getTypeForCompletion(const constraints::Solution &S, Expr *E) {
       return type;
     });
 
-    return S.simplifyType(completionTy.transform([&](Type type) {
+    Result = S.simplifyType(completionTy.transform([&](Type type) {
       if (auto *placeholder = type->getAs<PlaceholderType>()) {
         if (auto *typeVar =
                 placeholder->getOriginator().dyn_cast<TypeVariableType *>()) {
@@ -88,9 +90,17 @@ Type swift::ide::getTypeForCompletion(const constraints::Solution &S, Expr *E) {
 
       return type;
     }));
+  } else {
+    Result = S.getResolvedType(E);
   }
 
-  return S.getResolvedType(E);
+  if (!Result || Result->is<UnresolvedType>()) {
+    Result = CS.getContextualType(E, /*forConstraint=*/false);
+  }
+  if (Result && Result->is<UnresolvedType>()) {
+    Result = Type();
+  }
+  return Result;
 }
 
 bool swift::ide::isImplicitSingleExpressionReturn(ConstraintSystem &CS,

lib/IDE/UnresolvedMemberCompletion.cpp

@@ -89,7 +89,7 @@ void UnresolvedMemberTypeCheckCompletionCallback::sawSolution(
   // If the type couldn't be determined (e.g. because there isn't any context
   // to derive it from), let's not attempt to do a lookup since it wouldn't
   // produce any useful results anyway.
-  if (ExpectedTy && !ExpectedTy->is<UnresolvedType>()) {
+  if (ExpectedTy) {
     // If ExpectedTy is a duplicate of any other result, ignore this solution.
     if (!llvm::any_of(ExprResults, [&](const ExprResult &R) {
           return R.ExpectedTy->isEqual(ExpectedTy);

test/IDE/complete_assignment.swift

@@ -202,7 +202,7 @@ func f2() {
 // ASSIGN_11-DAG: Decl[InstanceMethod]/CurrNominal:   IntOpGen()[#Int?#]
 // ASSIGN_11-DAG: Decl[InstanceMethod]/CurrNominal:   D1Gen()[#D1#]
 // ASSIGN_11-DAG: Decl[InstanceMethod]/CurrNominal:   D2Gen()[#D2#]
-// ASSIGN_11-DAG: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]:   VoidGen()[#Void#]
+// ASSIGN_11-DAG: Decl[InstanceMethod]/CurrNominal:   VoidGen()[#Void#]
 // ASSIGN_11-DAG: Decl[InstanceVar]/CurrNominal:      InternalC2[#C2#]
 
   func f12() {