[CodeCompletion] Migrate yield completions to solver-based

We didn’t actually have any tests for this. Completions aren’t great here at the moment but since this is an underscored language feature it’s not that important at the moment.

Author: ahoppen

lib/IDE/CodeCompletion.cpp

@@ -1555,7 +1555,8 @@ bool CodeCompletionCallbacksImpl::trySolverCompletion(bool MaybeFuncBody) {
   case CompletionKind::ForEachSequence:
   case CompletionKind::PostfixExprBeginning:
   case CompletionKind::StmtOrExpr: 
-  case CompletionKind::ReturnStmtExpr: {
+  case CompletionKind::ReturnStmtExpr:
+  case CompletionKind::YieldStmtExpr: {
     assert(CurDeclContext);
 
     bool AddUnresolvedMemberCompletions =
@@ -1728,6 +1729,7 @@ void CodeCompletionCallbacksImpl::doneParsing(SourceFile *SrcFile) {
   case CompletionKind::PostfixExprParen:
   case CompletionKind::PostfixExpr:
   case CompletionKind::ReturnStmtExpr:
+  case CompletionKind::YieldStmtExpr:
     llvm_unreachable("should be already handled");
     return;
 
@@ -1976,19 +1978,6 @@ void CodeCompletionCallbacksImpl::doneParsing(SourceFile *SrcFile) {
     break;
   }
 
-  case CompletionKind::YieldStmtExpr: {
-    SourceLoc Loc = P.Context.SourceMgr.getIDEInspectionTargetLoc();
-    if (auto FD = dyn_cast<AccessorDecl>(CurDeclContext)) {
-      if (FD->isCoroutine()) {
-        // TODO: handle multi-value yields.
-        Lookup.setExpectedTypes(FD->getStorage()->getValueInterfaceType(),
-                                /*isImplicitSingleExpressionReturn*/ false);
-      }
-    }
-    Lookup.getValueCompletionsInDeclContext(Loc);
-    break;
-  }
-
   case CompletionKind::AfterPoundDirective: {
     addPoundDirectives(CompletionContext.getResultSink());
 

lib/IDE/ExprCompletion.cpp

@@ -78,7 +78,7 @@ void ExprTypeCheckCompletionCallback::sawSolutionImpl(
   auto &CS = S.getConstraintSystem();
 
   Type ExpectedTy;
-  if (auto ContextualType = CS.getContextualType(CompletionExpr, /*forConstraint=*/false)) {
+  if (auto ContextualType = S.getContextualType(CompletionExpr)) {
     ExpectedTy = ContextualType;
   } else {
     ExpectedTy = getTypeForCompletion(S, CompletionExpr);

lib/IDE/PostfixCompletion.cpp

@@ -177,12 +177,12 @@ void PostfixCompletionCallback::sawSolutionImpl(
 
   auto *Locator = CS.getConstraintLocator(SemanticExpr);
   Type ExpectedTy;
-  Expr *ParentExpr = CS.getParentExpr(CompletionExpr);
-  if (auto ContextualType = CS.getContextualType(CompletionExpr, /*forConstraint=*/false)) {
+  if (auto ContextualType = S.getContextualType(CompletionExpr)) {
     ExpectedTy = ContextualType;
   } else {
     ExpectedTy = getTypeForCompletion(S, CompletionExpr);
   }
+  Expr *ParentExpr = CS.getParentExpr(CompletionExpr);
 
   auto *CalleeLocator = S.getCalleeLocator(Locator);
   ValueDecl *ReferencedDecl = nullptr;

lib/Parse/ParseStmt.cpp

@@ -880,9 +880,10 @@ ParserResult<Stmt> Parser::parseStmtYield(SourceLoc tryLoc) {
     }
 
     auto expr = parseExpr(diag::expected_expr_yield);
-    if (expr.hasCodeCompletion())
-      return makeParserCodeCompletionResult<Stmt>();
-    if (expr.isParseErrorOrHasCompletion()) {
+    if (expr.hasCodeCompletion() && expr.isNonNull()) {
+      status |= expr;
+      yields.push_back(expr.get());
+    } else if (expr.isParseErrorOrHasCompletion()) {
       auto endLoc = (Tok.getLoc() == beginLoc ? beginLoc : PreviousLoc);
       yields.push_back(
         new (Context) ErrorExpr(SourceRange(beginLoc, endLoc)));

test/IDE/complete_yield.swift

@@ -0,0 +1,30 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-ide-test -batch-code-completion -source-filename %s -filecheck %raw-FileCheck -completion-output-dir %t
+
+struct YieldVariables {
+  var stringValue: String
+
+  var property: String {
+    _read {
+      yield #^IN_READ^#
+      // IN_READ-DAG: Decl[InstanceVar]/CurrNominal/TypeRelation[Convertible]: stringValue[#String#]; name=stringValue
+    }
+    _modify {
+      var localString = ""
+      yield #^IN_MODIFY^#
+      // IN_MODIFY-DAG: Decl[InstanceVar]/CurrNominal:      stringValue[#String#]; name=stringValue
+      // IN_MODIFY-DAG: Decl[LocalVar]/Local:               localString[#String#]; name=localString
+    }
+  }
+
+  var otherProperty: String {
+    _modify {
+      var localString = ""
+      yield &#^IN_MODIFY_WITH_REF^#
+      // FIXME: We should probably be returning a convertible type relation here.
+      // IN_MODIFY_WITH_REF: Decl[LocalVar]/Local:               localString[#String#]; name=localString
+      // IN_MODIFY_WITH_REF: Decl[InstanceVar]/CurrNominal:      stringValue[#String#]; name=stringValue
+    }
+  }
+}
+