LibWeb: Crash on https://www.apple.com/safari due to unresolved value for animation

[shannonbooth]

Reduced HTML page:

<style>
@keyframes globalnav-search-fade-and-slide {
        0% {
                transform: translateY(calc(var(--r-globalnav-search-shift-vertical)))
        }

        to {
                transform: translateY(0)
        }

}

.globalnav-searchresults {
        --r-globalnav-search-shift-vertical: 4px;
        animation-fill-mode: both;
        animation-name: globalnav-search-fade-and-slide;
}

</style>
<div class="globalnav-searchresults">

Segement of the backtrace:

Program received signal SIGILL, Illegal instruction.
ak_verification_failed (message=0x7fa395db9b98 "m_has_value at /home/shannon/personal/serenity/AK/Optional.h:224") at /home/shannon/personal/serenity/AK/Assertions.cpp:108
108         __builtin_trap();
(gdb) bt
#0  ak_verification_failed (message=0x7fa395db9b98 "m_has_value at /home/shannon/personal/serenity/AK/Optional.h:224") at /home/shannon/personal/serenity/AK/Assertions.cpp:108
#1  0x00007fa39537e8f1 in AK::Optional<Web::CSS::Angle>::release_value (this=0x7fff669ad5a0) at /home/shannon/personal/serenity/AK/Optional.h:224
#2  AK::Optional<Web::CSS::Angle>::value() && (this=0x7fff669ad5a0) at /home/shannon/personal/serenity/AK/Optional.h:219
#3  Web::CSS::AngleOrCalculated::resolve_calculated (this=<optimized out>, calculated=...) at /home/shannon/personal/serenity/Userland/Libraries/LibWeb/CSS/CalculatedOr.cpp:22
#4  0x00007fa39545278d in Web::CSS::CalculatedOr<Web::CSS::Angle>::resolved(Web::Layout::Node const&) const::{lambda(AK::NonnullRefPtr<Web::CSS::CalculatedStyleValue> const&)#1}::operator()(AK::NonnullRefPtr<Web::CSS::CalculatedStyleValue> const&) const (calculated=..., this=<optimized out>) at /home/shannon/personal/serenity/Userland/Libraries/LibWeb/CSS/CalculatedOr.h:64
#5  _ZN2AK6Detail9VisitImplIhJN3Web3CSS5AngleENS_13NonnullRefPtrINS3_20CalculatedStyleValueEEEEE5visitIKNS_7VariantIJS4_S7_EEENSB_7VisitorIJZNKS3_12CalculatedOrIS4_E8resolvedERKNS2_6Layout4NodeEEUlRKS4_E_ZNKSF_8resolvedESJ_EUlRKS7_E_EEELh1EEEDcRT_hPKvOT0_QltTL0_1_sZT0_ (self=..., id=<optimized out>, data=<optimized out>, visitor=...)
    at /home/shannon/personal/serenity/AK/Variant.h:112
#6  _ZN2AK6Detail9VisitImplIhJN3Web3CSS5AngleENS_13NonnullRefPtrINS3_20CalculatedStyleValueEEEEE5visitIKNS_7VariantIJS4_S7_EEENSB_7VisitorIJZNKS3_12CalculatedOrIS4_E8resolvedERKNS2_6Layout4NodeEEUlRKS4_E_ZNKSF_8resolvedESJ_EUlRKS7_E_EEELh0EEEDcRT_hPKvOT0_QltTL0_1_sZT0_ (self=..., data=0x0, id=<optimized out>, visitor=...) at /home/shannon/personal/serenity/AK/Variant.h:118
#7  AK::Variant<Web::CSS::Angle, AK::NonnullRefPtr<Web::CSS::CalculatedStyleValue> >::visit<Web::CSS::CalculatedOr<Web::CSS::Angle>::resolved(Web::Layout::Node const&) const::{lambda(Web::CSS::Angle const&)#1}, Web::CSS::CalculatedOr<Web::CSS::Angle>::resolved(Web::Layout::Node const&) const::{lambda(AK::NonnullRefPtr<Web::CSS::CalculatedStyleValue> const&)#1}>(Web::CSS::CalculatedOr<Web::CSS::Angle>::resolved(Web::Layout::Node const&) const::{lambda(Web::CSS::Angle const&)#1}&&, Web::CSS::CalculatedOr<Web::CSS::Angle>::resolved(Web::Layout::Node const&) const::{lambda(AK::NonnullRefPtr<Web::CSS::CalculatedStyleValue> const&)#1}&&) const (this=0x0, functions=..., functions=...) at /home/shannon/personal/serenity/AK/Variant.h:430
#8  Web::CSS::CalculatedOr<Web::CSS::Angle>::resolved (this=0x7fa393f39c80 <main_arena>, layout_node=...)
    at /home/shannon/personal/serenity/Userland/Libraries/LibWeb/CSS/CalculatedOr.h:59
#9  Web::CSS::Transformation::to_matrix(AK::Optional<Web::Painting::PaintableBox const&>) const::$_0::operator()(unsigned long, Web::CSSPixels const&) const::{lambda(Web::CSS::AngleOrCalculated const&)#1}::operator()(Web::CSS::AngleOrCalculated const&) const (value=..., this=<optimized out>)
    at /home/shannon/personal/serenity/Userland/Libraries/LibWeb/CSS/Transformation.cpp:35
#10 _ZN2AK6Detail9VisitImplIhJN3Web3CSS17AngleOrCalculatedENS3_16LengthPercentageENS3_16NumberPercentageEEE5visitIKNS_7VariantIJS4_S5_S6_EEENSA_7VisitorIJZZNKS3_14Transformation9to_matrixENS_8OptionalIRKNS2_8Painting12PaintableBoxEEEENK3$_0clEmRKNS2_9CSSPixelsEEUlRKS5_E_ZZNKSD_9to_matrixESJ_ENKSK_clEmSN_EUlRKS4_E_ZZNKSD_9to_matrixESJ_ENKSK_clEmSN_EUlRKS6_E_EEELh0EEEDcRT_hPKvOT0_QltTL0_1_sZT0_ (self=..., data=0x7fa393f39c80 <main_arena>, id=<optimized out>, visitor=...) at /home/shannon/personal/serenity/AK/Variant.h:112
#11 AK::Variant<Web::CSS::AngleOrCalculated, Web::CSS::LengthPercentage, Web::CSS::NumberPercentage>::visit<Web::CSS::Transformation::to_matrix(AK::Optional<Web::Painting::PaintableBox const&>) const::$_0::operator()(unsigned long, Web::CSSPixels const&) const::{lambda(Web::CSS::LengthPercentage const&)#1}, Web::CSS::Transformation::to_matrix(AK::Optional<Web::Painting::PaintableBox const&>) const::$_0::operator()(unsigned long, Web::CSSPixels const&) const::{lambda(Web::CSS::AngleOrCalculated const&)#1}, Web::CSS::Transformation::to_matrix(AK::Optional<Web::Painting::PaintableBox const&>) const::$_0::operator()(unsigned long, Web::CSSPixels const&) const::{lambda(Web::CSS::NumberPercentage const&)#1}>(Web::CSS::Transformation::to_matrix(AK::Optional<Web::Painting::PaintableBox const&>) const::$_0::operator()(unsigned long, Web::CSSPixels const&) const::{lambda(Web::CSS::LengthPercentage const&)#1}&&, Web::CSS::Transformation::to_matrix(AK::Optional<Web::Painting::PaintableBox const&>) const::$_0::operator()(unsigned long, Web::CSSPixels const&) const::{lambda(Web::CSS::AngleOrCalculated const&)#1}&&, Web::CSS::Transformation::to_matrix(AK::Optional<Web::Painting::PaintableBox const&>) const::$_0::operator()(unsigned long, Web::CSSPixels const&) const::{lambda(Web::CSS::NumberPercentage const&)#1}&&) const (this=0x7fa393f39c80 <main_arena>, functions=..., functions=..., functions=...) at /home/shannon/personal/serenity/AK/Variant.h:430
#12 Web::CSS::Transformation::to_matrix(AK::Optional<Web::Painting::PaintableBox const&>) const::$_0::operator()(unsigned long, Web::CSSPixels const&) const (
    this=this@entry=0x7fff669ad6b8, index=index@entry=0, reference_length=...) at /home/shannon/personal/serenity/Userland/Libraries/LibWeb/CSS/Transformation.cpp:23
#13 0x00007fa395451150 in Web::CSS::Transformation::to_matrix (this=0x7fff669ad7f0, paintable_box=...)
    at /home/shannon/personal/serenity/Userland/Libraries/LibWeb/CSS/Transformation.cpp:115
#14 0x00007fa39541c01d in Web::CSS::interpolate_transform(Web::DOM::Element&, Web::CSS::StyleValue const&, Web::CSS::StyleValue const&, float)::$_4::operator()(Web::DOM::Element&, Web::CSS::TransformationStyleValue const&) const (this=<optimized out>, element=..., value=...) at /home/shannon/personal/serenity/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp:901
#15 0x00007fa39541ac90 in Web::CSS::interpolate_transform(Web::DOM::Element&, Web::CSS::StyleValue const&, Web::CSS::StyleValue const&, float)::$_1::operator()(Web::DOM::Element&, Web::CSS::StyleValue const&) const (this=<optimized out>, element=..., value=...) at /home/shannon/personal/serenity/Userland/Libraries/LibWeb/CSS/StyleComputer.cpp:917