[NFC] Additional DeclNameRef auditing

Author: beccadax

lib/Sema/CSApply.cpp

@@ -7404,12 +7404,13 @@ Expr *ExprRewriter::coerceToType(Expr *expr, Type toType,
 
     case ConversionRestrictionKind::CGFloatToDouble:
     case ConversionRestrictionKind::DoubleToCGFloat: {
-      DeclName name(ctx, DeclBaseName::createConstructor(), Identifier());
+      // OK: Implicit conversion, no module selector to drop here.
+      DeclNameRef initRef(ctx, /*module selector=*/Identifier(),
+                          DeclBaseName::createConstructor(), { Identifier() });
 
       ConstructorDecl *decl = nullptr;
       SmallVector<ValueDecl *, 2> candidates;
-      dc->lookupQualified(toType->getAnyNominal(),
-                          DeclNameRef(name), SourceLoc(),
+      dc->lookupQualified(toType->getAnyNominal(), initRef, SourceLoc(),
                           NL_QualifiedDefault, candidates);
       for (auto *candidate : candidates) {
         auto *ctor = cast<ConstructorDecl>(candidate);

lib/Sema/CSGen.cpp

@@ -3809,10 +3809,9 @@ namespace {
           componentTypeVars.push_back(memberTy);
           auto lookupName =
               kind == KeyPathExpr::Component::Kind::UnresolvedMember
-                  ? DeclNameRef(
-                        component.getUnresolvedDeclName()) // FIXME: type change
-                                                           // needed
-                  : component.getDeclRef().getDecl()->createNameRef();
+                  ? component.getUnresolvedDeclName()
+                  : component.getDeclRef().getDecl()->createNameRef(
+                                                          /*modSel=*/true);
 
           auto refKind = component.getFunctionRefInfo();
           CS.addValueMemberConstraint(base, lookupName, memberTy, CurDC,
@@ -5227,10 +5226,14 @@ ResolvedMemberResult swift::resolveValueMember(DeclContext &DC, Type BaseTy,
   ResolvedMemberResult Result;
   ConstraintSystem CS(&DC, std::nullopt);
 
+  // OK: By contract, `Name` should be derived from an existing Decl, not a
+  // name written by the user in source code. So when used as intended, we won't
+  // be dropping a module selector here.
+  DeclNameRef NameRef(Name);
   // Look up all members of BaseTy with the given Name.
   MemberLookupResult LookupResult =
-      CS.performMemberLookup(ConstraintKind::ValueMember, DeclNameRef(Name),
-                             BaseTy, FunctionRefInfo::singleBaseNameApply(),
+      CS.performMemberLookup(ConstraintKind::ValueMember, NameRef, BaseTy,
+                             FunctionRefInfo::singleBaseNameApply(),
                              CS.getConstraintLocator({}), false);
 
   // Keep track of all the unviable members.

lib/Sema/CSSimplify.cpp

@@ -8488,6 +8488,9 @@ ConstraintSystem::simplifyConstructionConstraint(
   // variable T. T2 is the result type provided via the construction
   // constraint itself.
   addValueMemberConstraint(MetatypeType::get(valueType, getASTContext()),
+                           // OK: simplifyConstructionConstraint() is only used
+                           // for `T(...)` init calls, not `T.init(...)` calls,
+                           // so there's no module selector on `init`.
                            DeclNameRef::createConstructor(),
                            memberType,
                            useDC, functionRefInfo,

lib/Sema/TypeCheckAttr.cpp

@@ -3163,10 +3163,11 @@ SynthesizeMainFunctionRequest::evaluate(Evaluator &evaluator,
     }
 
     CS.addDisjunctionConstraint(typeEqualityConstraints, locator);
-    CS.addValueMemberConstraint(
-        nominal->getInterfaceType(), DeclNameRef(context.Id_main),
-        Type(mainType), declContext, FunctionRefInfo::singleBaseNameApply(), {},
-        locator);
+    CS.addValueMemberConstraint(nominal->getInterfaceType(),
+                                DeclNameRef(context.Id_main), // OK: Generated
+                                Type(mainType), declContext,
+                                FunctionRefInfo::singleBaseNameApply(), {},
+                                locator);
   }
 
   FuncDecl *mainFunction = nullptr;

test/NameLookup/module_selector.swift

@@ -11,6 +11,8 @@
 // * Whether we handle access paths correctly
 // * Interaction with ClangImporter
 // * Cross-import overlays
+// * Key paths
+// * Key path dynamic member lookup
 //
 // It also might not cover all combinations of name lookup paths and inputs.