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C++ Interop: support mutating attribute for C++ methods #39999

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Merged
merged 1 commit into from
Nov 30, 2021
Merged

C++ Interop: support mutating attribute for C++ methods #39999

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9 changes: 8 additions & 1 deletion lib/ClangImporter/ClangImporter.cpp
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Expand Up @@ -4351,7 +4351,14 @@ ClangImporter::instantiateCXXClassTemplate(

bool ClangImporter::isCXXMethodMutating(const clang::CXXMethodDecl *method) {
return isa<clang::CXXConstructorDecl>(method) || !method->isConst() ||
method->getParent()->hasMutableFields();
method->getParent()->hasMutableFields() ||
(method->hasAttrs() &&
llvm::any_of(method->getAttrs(), [](clang::Attr *a) {
if (auto swiftAttr = dyn_cast<clang::SwiftAttrAttr>(a)) {
return swiftAttr->getAttribute() == "mutating";
}
return false;
}));
}

SwiftLookupTable *
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5 changes: 5 additions & 0 deletions test/Interop/Cxx/class/Inputs/module.modulemap
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Expand Up @@ -53,6 +53,11 @@ module MutableMembers {
requires cplusplus
}

module MutabilityAnnotations {
header "mutability-annotations.h"
requires cplusplus
}

module ProtocolConformance {
header "protocol-conformance.h"
requires cplusplus
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18 changes: 18 additions & 0 deletions test/Interop/Cxx/class/Inputs/mutability-annotations.h
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@@ -0,0 +1,18 @@
#ifndef TEST_INTEROP_CXX_CLASS_INPUTS_MUTABILITY_ANNOTATIONS_H
#define TEST_INTEROP_CXX_CLASS_INPUTS_MUTABILITY_ANNOTATIONS_H

struct HasConstMethodAnnotatedAsMutating {
int a;

int annotatedMutating() const __attribute__((__swift_attr__("mutating"))) {
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@zoecarver zoecarver Nov 1, 2021 •
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Maybe a test where there are multiple swift_attr attributes. Also, you can spell it like this: struct __attribute__((swift_attr("mutating"))) X { };.

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Maybe a test where there are multiple swift_attr attributes

Good idea, I added a test.

Also, you can spell it like this: struct __attribute__((swift_attr("mutating"))) X { };.

Hmm, that currently produces mutating struct X which doesn't look right, but it also worked this way before this change :)
Do you think mutating on a struct should apply it to all members methods?

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Do you think mutating on a struct should apply it to all members methods?

Hmm, I don't know. But the test looks good how it is now. I think that's the correct way to write it.

const_cast<HasConstMethodAnnotatedAsMutating *>(this)->a++;
return a;
}

int annotatedMutatingWithOtherAttrs() const __attribute__((__swift_attr__("public"))) __attribute__((__swift_attr__("mutating"))) {
const_cast<HasConstMethodAnnotatedAsMutating *>(this)->a++;
return a;
}
};

#endif // TEST_INTEROP_CXX_CLASS_INPUTS_MUTABILITY_ANNOTATIONS_H
7 changes: 7 additions & 0 deletions test/Interop/Cxx/class/mutability-annotations-module-interface.swift
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@@ -0,0 +1,7 @@
// RUN: %target-swift-ide-test -print-module -module-to-print=MutabilityAnnotations -I %S/Inputs -source-filename=x -enable-cxx-interop | %FileCheck %s

// CHECK: struct HasConstMethodAnnotatedAsMutating {
// CHECK: mutating func annotatedMutating() -> Int32
// CHECK: mutating func annotatedMutatingWithOtherAttrs() -> Int32
// CHECK: var a: Int32
// CHECK: }
6 changes: 6 additions & 0 deletions test/Interop/Cxx/class/mutability-annotations-typechecker.swift
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@@ -0,0 +1,6 @@
// RUN: %target-typecheck-verify-swift -I %S/Inputs -enable-cxx-interop

import MutabilityAnnotations

let obj = HasConstMethodAnnotatedAsMutating(a: 42) // expected-note {{change 'let' to 'var' to make it mutable}}
let i = obj.annotatedMutating() // expected-error {{cannot use mutating member on immutable value: 'obj' is a 'let' constant}}