Sema: remove TypeResolver::diagnoseMoveOnlyGeneric

Author: kavon

lib/Sema/TypeCheckType.cpp

@@ -2106,9 +2106,6 @@ namespace {
       repr->setInvalid();
       return diags.diagnose(std::forward<ArgTypes>(Args)...);
     }
-
-    bool diagnoseMoveOnlyGeneric(TypeRepr *repr,
-                                 Type unboundTy, Type genericArgTy);
 
     bool diagnoseDisallowedExistential(TypeRepr *repr);
 
@@ -2500,33 +2497,6 @@ bool TypeResolver::diagnoseInvalidPlaceHolder(OpaqueReturnTypeRepr *repr) {
   return false;
 }
 
-/// Checks the given type, assuming that it appears as an argument for a
-/// generic parameter in the \c repr, to see if it is move-only.
-///
-/// Because generic type parameters currently all assume copyability of
-/// the substituted type, it's an error for a move-only type to appear
-/// as an argument for type parameters.
-///
-/// returns true if an error diagnostic was emitted
-bool TypeResolver::diagnoseMoveOnlyGeneric(TypeRepr *repr,
-                                           Type unboundTy,
-                                           Type genericArgTy) {
-  if (getASTContext().LangOpts.hasFeature(Feature::NoncopyableGenerics))
-    return false;
-
-  if (genericArgTy->isNoncopyable()) {
-    if (unboundTy) {
-      diagnoseInvalid(repr, repr->getLoc(), diag::noncopyable_generics_specific,
-                      genericArgTy, unboundTy);
-    } else {
-      diagnoseInvalid(repr, repr->getLoc(), diag::noncopyable_generics,
-                      genericArgTy);
-    }
-    return true;
-  }
-  return false;
-}
-
 
 bool swift::diagnoseMissingOwnership(ParamSpecifier ownership,
                                      TypeRepr *repr, Type ty,
@@ -5011,17 +4981,26 @@ NeverNullType TypeResolver::resolveArrayType(ArrayTypeRepr *repr,
   // If the standard library isn't loaded, we ought to let the user know
   // something has gone terribly wrong, since the rest of the compiler is going
   // to assume it can canonicalize [T] to Array<T>.
-  if (!ctx.getArrayDecl()) {
-    ctx.Diags.diagnose(repr->getBrackets().Start,
-                       diag::sugar_type_not_found, 0);
-    return ErrorType::get(ctx);
-  }
+  {
+    // Check that we can validly substitute the baseTy into an array. We do not
+    // actually resolve to that valid array type, as we want to return the
+    // sugared Type node ArraySliceType instead!
+    auto *arrayDecl = ctx.getArrayDecl();
+    if (!arrayDecl) {
+      ctx.Diags.diagnose(repr->getBrackets().Start,
+                         diag::sugar_type_not_found, 0);
+      return ErrorType::get(ctx);
+    }
 
-  // do not allow move-only types in an array
-  if (diagnoseMoveOnlyGeneric(repr,
-                              ctx.getArrayDecl()->getDeclaredInterfaceType(),
-                              baseTy)) {
-    return ErrorType::get(ctx);
+    Type genericArgs[1] = {baseTy};
+    auto arrayTy =
+        resolution.applyUnboundGenericArguments(arrayDecl,
+            /*parentTy=*/nullptr,
+                                                repr->getBrackets().Start,
+                                                genericArgs);
+    if (arrayTy->hasError()) {
+      return ErrorType::get(ctx);
+    }
   }
 
   return ArraySliceType::get(baseTy);
@@ -5116,11 +5095,17 @@ NeverNullType TypeResolver::resolveOptionalType(OptionalTypeRepr *repr,
     return ErrorType::get(ctx);
   }
 
-  // do not allow move-only types in an optional
-  if (diagnoseMoveOnlyGeneric(repr,
-                              ctx.getOptionalDecl()->getDeclaredInterfaceType(),
-                              baseTy)) {
-    return ErrorType::get(ctx);
+  {
+    // Check that we can validly substitute the baseTy into an Optional
+    Type genericArgs[1] = {baseTy};
+    auto substTy =
+        resolution.applyUnboundGenericArguments(ctx.getOptionalDecl(),
+                                                /*parentTy=*/nullptr,
+                                                repr->getQuestionLoc(),
+                                                genericArgs);
+    if (substTy->hasError()) {
+      return ErrorType::get(ctx);
+    }
   }
 
   return optionalTy;
@@ -5221,11 +5206,17 @@ NeverNullType TypeResolver::resolveImplicitlyUnwrappedOptionalType(
     return ErrorType::get(ctx);
   }
 
-  // do not allow move-only types in an implicitly-unwrapped optional
-  if (diagnoseMoveOnlyGeneric(repr,
-                              ctx.getOptionalDecl()->getDeclaredInterfaceType(),
-                              baseTy)) {
-    return ErrorType::get(ctx);
+  {
+    // Check that we can validly substitute the baseTy into an Optional
+    Type genericArgs[1] = {baseTy};
+    auto substTy =
+        resolution.applyUnboundGenericArguments(ctx.getOptionalDecl(),
+            /*parentTy=*/nullptr,
+                                                repr->getExclamationLoc(),
+                                                genericArgs);
+    if (substTy->hasError()) {
+      return ErrorType::get(ctx);
+    }
   }
 
   return uncheckedOptionalTy;

lib/Sema/TypeChecker.h

@@ -286,6 +286,8 @@ enum class CheckedCastContextKind {
 };
 
 namespace TypeChecker {
+// DANGER: callers must verify that elementType satisfies the requirements of
+// the Wrapped generic parameter, as this function will not do so!
 Type getOptionalType(SourceLoc loc, Type elementType);
 
 /// Bind an UnresolvedDeclRefExpr by performing name lookup and

test/Generics/inverse_generics.swift

@@ -484,3 +484,14 @@ struct SSS: ~Copyable, PPP {}
 protocol PPP: ~Copyable {}
 let global__old__: any PPP = SSS() // expected-error {{value of type 'SSS' does not conform to specified type 'Copyable'}}
 let global__new__: any PPP & ~Copyable = SSS()
+
+
+struct Example<T> {}
+
+struct TestResolution {
+  var maybeNC: NC? = nil // expected-error {{type 'NC' does not conform to protocol 'Copyable'}}
+  var maybeIOUNC: NC! = nil // expected-error {{type 'NC' does not conform to protocol 'Copyable'}}
+  var arrayNC: [NC] = [] // expected-error {{type 'NC' does not conform to protocol 'Copyable'}}
+  var dictNC: [String: NC] = [:] // expected-error {{type 'NC' does not conform to protocol 'Copyable'}}
+  var exampleNC: Example<NC> = Example() // expected-error {{type 'NC' does not conform to protocol 'Copyable'}}
+}