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Support 'as UInt8' in @section expressions #85412

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Merged
merged 1 commit into from
Nov 11, 2025
+13 −2
Merged

Support 'as UInt8' in @section expressions #85412

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10 changes: 10 additions & 0 deletions lib/Sema/LegalConstExprVerifier.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -176,6 +176,16 @@ checkSupportedWithSectionAttribute(const Expr *expr,
// Non-InlineArray arrays are not allowed
return std::make_pair(expr, TypeNotSupported);
}

// Coerce expressions to UInt8 are allowed (to support @DebugDescription)
if (const CoerceExpr *coerceExpr = dyn_cast<CoerceExpr>(expr)) {
auto coerceType = coerceExpr->getType();
if (coerceType && coerceType->isUInt8()) {
expressionsToCheck.push_back(coerceExpr->getSubExpr());
continue;
}
return std::make_pair(expr, TypeNotSupported);
}

// Operators are not allowed in @section expressions
if (isa<BinaryExpr>(expr)) {
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5 changes: 3 additions & 2 deletions test/ConstValues/SectionSyntactic.swift
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Expand Up @@ -35,8 +35,8 @@
// non-literal expressions (should be rejected)
@section("mysection") let invalidNonLiteral1 = Int.max
// expected-error@-1{{not supported in a constant expression}}
@section("mysection") let invalidNonLiteral2 = UInt8(42)
// expected-error@-1{{not supported in a constant expression}}
@section("mysection") let invalidNonLiteral2 = UInt64(42)
// expected-error@-1{{unsupported type in a constant expression}}
@section("mysection") let invalidNonLiteral3 = true.hashValue
// expected-error@-1{{not supported in a constant expression}}

Expand Down Expand Up @@ -85,6 +85,7 @@ enum E { case a }
@section("mysection") let tuple1 = (1, 2, 3, 2.718, true) // ok
@section("mysection") let tuple2: (Int, Float, Bool) = (42, 3.14, false) // ok
@section("mysection") let tuple3 = (foo, bar) // ok (function references in tuple)
@section("mysection") let tuple4 = (1 as UInt8, 2 as UInt8, 3 as UInt8) // ok

// invalid tuples (should be rejected)
@section("mysection") let invalidTuple1 = (1, 2, Int.max)
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