VSCode C++ bug

main.cpp

#include <array>
#include <d2d1.h>
#include <iostream>

#include "SColour.hpp"

constexpr uint8_t HueGradientPrecision = 20; // Number of steps in the hue gradient
constexpr const std::array<D2D1_GRADIENT_STOP, HueGradientPrecision> CalculateHueGradient()
{
	std::array<D2D1_GRADIENT_STOP, HueGradientPrecision> gradientStops{};

	SColour tempcol{};
	tempcol.h = 359;
	tempcol.s = 100;
	tempcol.v = 100;
	tempcol.UpdateRGB();

	const float step = 359 / (float)HueGradientPrecision;

	for (uint8_t i = 0; i < HueGradientPrecision; i++)
	{
		// Due to some weird MSBuild thing, C++17 is half implemented in Clang-CL.
		// Because of that, we don't have constexpr operator[] on std::array.
		// Access the raw underlying array directly instead.
		gradientStops._Elems[i] = {
			i / (float)(HueGradientPrecision - 1),
			{
				tempcol.r / 255.0f,
				tempcol.g / 255.0f,
				tempcol.b / 255.0f,
				1.0f
			}
		};

		// Clang errors out on the use of -= here
		tempcol.h = tempcol.h - step;
		tempcol.UpdateRGB();
	}

	return gradientStops;
}

inline const auto &GetHueGradient()
{
	static constexpr auto value = CalculateHueGradient();
	return value;
}

int main()
{
	std::cout << GetHueGradient()[10].position;
}

SColour.hpp

#pragma once
#include <algorithm>
#include <cstdint>

struct SColour {

	// Red, green and blue
	uint8_t r, g, b;

	// Hue, saturation and value
	unsigned short h;
	uint8_t s, v;

	// Alpha
	uint8_t a;

#pragma warning(push)
#pragma warning(disable: 4244)
	// Updates RGB from HSV
	constexpr void UpdateRGB()
	{
		const float val = v / 100.0f;

		if (s == 0) // Acromatic color (gray). Hue doesn't mind.
		{
			r = b = g = 255.0f * val;
			return;
		}

		const float base = 255.0f * (1.0f - (s / 100.0f)) * val;

		switch (h / 60)
		{
		case 0:
			r = 255.0f * val;
			g = (255.0f * val - base) * (h / 60.0f) + base;
			b = base;
			break;

		case 1:
			r = (255.0f * val - base) * (1.0f - ((h % 60) / 60.0f)) + base;
			g = 255.0f * val;
			b = base;
			break;

		case 2:
			r = base;
			g = 255.0f * val;
			b = (255.0f * val - base) * ((h % 60) / 60.0f) + base;
			break;

		case 3:
			r = base;
			g = (255.0f * val - base) * (1.0f - ((h % 60) / 60.0f)) + base;
			b = 255.0f * val;
			break;

		case 4:
			r = (255.0f * val - base) * ((h % 60) / 60.0f) + base;
			g = base;
			b = 255.0f * val;
			break;

		case 5:
			r = 255.0f * val;
			g = base;
			b = (255.0f * val - base) * (1.0f - ((h % 60) / 60.0f)) + base;
			break;
		}
	}

	// Updates HSV from RGB
	constexpr void UpdateHSV()
	{
		const uint8_t &max = (std::max)((std::max)(r, g), b);
		const uint8_t &min = (std::min)((std::min)(r, g), b);
		const float delta = max - min;

		if (max == 0)
		{
			s = h = v = 0;
			return;
		}

		v = max / 255.0f * 100.0f;
		s = delta / (float)max * 100.0f;

		short temp = 0;
		if (r == max)
		{
			temp = 60 * ((g - b) / delta);
		}
		else if (g == max)
		{
			temp = 60 * (2 + (b - r) / delta);
		}
		else
		{
			temp = 60 * (4 + (r - g) / delta);
		}

		if (temp < 0)
		{
			h = temp + 360;
		}
		else
		{
			h = temp;
		}
	}
#pragma warning(pop)
};