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Fix the static_functions_not_mutating error messsage #78052

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Fix the static_functions_not_mutating error messsage #78052

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5 changes: 4 additions & 1 deletion include/swift/AST/DiagnosticsSema.def
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Original file line number Diff line number Diff line change
Expand Up @@ -1735,7 +1735,10 @@ ERROR(functions_mutating_and_not,none,
"method must not be declared both %0 and %1",
(SelfAccessKind, SelfAccessKind))
ERROR(static_functions_not_mutating,none,
"static functions must not be declared mutating", ())
"%0 modifier cannot be used on static functions",
(SelfAccessKind))
Comment on lines +1738 to +1739
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If you incorporate the declaration like so, the message will be also be tailored for an accessor:

Suggested change
"%0 modifier cannot be used on static functions",
(SelfAccessKind))
"%0 modifier cannot be used on %kindonly1",
(SelfAccessKind, const FuncDecl *))

We loose the plural, but I think that’s fine because the object remains indefinite.

NOTE(static_functions_not_mutating_detail,none,
"static members cannot access instance properties or self", ())
Comment on lines +1740 to +1741
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I’m not a fan of this interpretation because it’s misleading. We have this very problem with another diagnostic: #62909. You can access both self or instance members inside a static method depending on what you mean by it.

Maybe we could borrow a more clear phrasing from the book. For example:

static members are defined on the type itself rather than on instances of the type
static members belong to the type itself rather than to instances of the type
static members are members of the type itself rather than instances of the type


ERROR(readwriter_mutatingness_differs_from_reader_or_writer_mutatingness,none,
"%0 cannot be %1 when "
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6 changes: 4 additions & 2 deletions lib/Sema/TypeCheckAttr.cpp
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Expand Up @@ -785,8 +785,10 @@ void AttributeChecker::visitMutationAttr(DeclAttribute *attr) {
}
}
// Verify that we don't have a static function.
if (FD->isStatic())
diagnoseAndRemoveAttr(attr, diag::static_functions_not_mutating);
if (FD->isStatic()) {
diagnoseAndRemoveAttr(attr, diag::static_functions_not_mutating, attrModifier);
diagnose(FD, diag::static_functions_not_mutating_detail);
}
}

void AttributeChecker::visitDynamicAttr(DynamicAttr *attr) {
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3 changes: 2 additions & 1 deletion test/Sema/immutability.swift
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Expand Up @@ -131,7 +131,8 @@ struct SomeStruct {

static let type_let = 5 // expected-note {{change 'let' to 'var' to make it mutable}} {{10-13=var}}

mutating static func f() { // expected-error {{static functions must not be declared mutating}} {{3-12=}}
mutating static func f() { // expected-error {{'mutating' modifier cannot be used on static functions}} {{3-12=}}
// expected-note@-1 {{static members cannot access instance properties or self}}
}

mutating func g() {
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3 changes: 2 additions & 1 deletion test/decl/overload.swift
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Expand Up @@ -410,7 +410,8 @@ protocol ProtocolWithMutating {
mutating func test2(_ a: Int?) // expected-note {{previously declared}}
func test2(_ a: Int!) // expected-error{{invalid redeclaration of 'test2'}}

mutating static func classTest1() // expected-error {{static functions must not be declared mutating}} {{3-12=}} expected-note {{previously declared}}
mutating static func classTest1() // expected-error {{'mutating' modifier cannot be used on static functions}} {{3-12=}} expected-note {{previously declared}}
// expected-note@-1 {{static members cannot access instance properties or self}}
static func classTest1() // expected-error{{invalid redeclaration of 'classTest1()'}}
}

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6 changes: 4 additions & 2 deletions test/decl/subscript/static.swift
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Expand Up @@ -20,8 +20,10 @@ func useMyStruct() {

struct BadStruct {
static subscript(_ i: Int) -> String {
nonmutating get { fatalError() } // expected-error{{static functions must not be declared mutating}}
mutating set { fatalError() } // expected-error{{static functions must not be declared mutating}}
nonmutating get { fatalError() } // expected-error {{'nonmutating' modifier cannot be used on static functions}}
// expected-note@-1 {{static members cannot access instance properties or self}}
mutating set { fatalError() } // expected-error {{'mutating' modifier cannot be used on static functions}}
// expected-note@-1 {{static members cannot access instance properties or self}}
}
}

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