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[AST] Temporarily downgrade value generic redeclaration to warning #81104

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Merged
merged 2 commits into from
Apr 26, 2025
Merged

[AST] Temporarily downgrade value generic redeclaration to warning #81104

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687b3f5
Downgrade redeclaration with value generic arg to warning right now
Azoy Apr 25, 2025
0d5b53d
Update value_generics.swift
Azoy Apr 25, 2025
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9 changes: 7 additions & 2 deletions include/swift/AST/Decl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -310,6 +310,9 @@ struct OverloadSignature {
/// Whether this is a macro.
unsigned IsMacro : 1;

/// Whether this is a generic argument.
unsigned IsGenericArg : 1;

/// Whether this signature is part of a protocol extension.
unsigned InProtocolExtension : 1;

Expand All @@ -323,8 +326,10 @@ struct OverloadSignature {
OverloadSignature()
: UnaryOperator(UnaryOperatorKind::None), IsInstanceMember(false),
IsVariable(false), IsFunction(false), IsAsyncFunction(false),
IsDistributed(false), InProtocolExtension(false),
InExtensionOfGenericType(false), HasOpaqueReturnType(false) { }
IsDistributed(false), IsEnumElement(false), IsNominal(false),
IsTypeAlias(false), IsMacro(false), IsGenericArg(false),
InProtocolExtension(false), InExtensionOfGenericType(false),
HasOpaqueReturnType(false) { }
};

/// Determine whether two overload signatures conflict.
Expand Down
8 changes: 8 additions & 0 deletions lib/AST/Decl.cpp
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Expand Up @@ -3859,6 +3859,13 @@ bool swift::conflicting(ASTContext &ctx,
if (sig1.IsFunction != sig2.IsFunction)
return true;

// Gracefully handle the case where value generic arguments were introduced
// as a conflicting value with static variables of the same name.
if (sig1.IsGenericArg != sig2.IsGenericArg) {
*wouldConflictInSwift5 = true;
return true;
}

// Variables always conflict with non-variables with the same signature.
// (e.g variables with zero argument functions, variables with type
// declarations)
Expand Down Expand Up @@ -4037,6 +4044,7 @@ OverloadSignature ValueDecl::getOverloadSignature() const {
signature.IsNominal = isa<NominalTypeDecl>(this);
signature.IsTypeAlias = isa<TypeAliasDecl>(this);
signature.IsMacro = isa<MacroDecl>(this);
signature.IsGenericArg = isa<GenericTypeParamDecl>(this);
signature.HasOpaqueReturnType =
!signature.IsVariable && (bool)getOpaqueResultTypeDecl();

Expand Down
4 changes: 2 additions & 2 deletions test/Sema/value_generics.swift
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Expand Up @@ -121,7 +121,7 @@ func testC4<let T: Int>(with c: C<T, T>) {
struct D<let N: Int & P> {} // expected-error {{non-protocol, non-class type 'Int' cannot be used within a protocol-constrained type}}

struct E<A, let b: Int> { // expected-note {{'b' previously declared here}}
static var b: Int { // expected-error {{invalid redeclaration of 'b'}}
static var b: Int { // expected-warning {{redeclaration of 'b' is deprecated and will be an error in Swift 5}}
// expected-note@-1 {{'b' declared here}}
123
}
Expand Down Expand Up @@ -183,7 +183,7 @@ func testTypeOf2<let c: Int>(_: E<Int, c>.Type) -> Int {
}

struct H<let I: Int> { // expected-note {{'I' previously declared here}}
struct I {} // expected-error {{invalid redeclaration of 'I'}}
struct I {} // expected-warning {{redeclaration of 'I' is deprecated and will be an error in Swift 5}}
}

typealias J = E<Int, 123>.b // expected-error {{static property 'b' is not a member type of 'E<Int, 123>'}}