Yes. The governments of the world switched recognition from the Republic of China to the People's Republic of China, and transferred "China's" UN Security Council seat to the PRC.
> However, it seems clear that at least most western countries see Taiwan as its own country in practice.
They maintain informal ties, but not formal diplomatic ties. Even the PRC has informal ties with the ROC.
> surprised to hear that Taiwan isn't supposed to be its own country
It's perhaps surprising, given Taiwan's de facto independence, but legally, it's not that surprising. Taiwan was a part of China, and it's difficult to define a point in time at which it ceased to be so. Both the ROC and PRC agreed that Taiwan was part of China for decades after the end of the civil war. The Taiwanese independence movement, which has become much stronger over the last 20 years, has changed sentiment in Taiwan itself. However, it would be a major step for other countries to decide that Taiwan no longer legally belongs to China.
> However, it would be a major step for other countries to decide that Taiwan no longer legally belongs to China.
What one means by belongs to China is another matter. Not saying you have, but people will conflate the government of China with China. Taiwan does not belong the current ruling government of China and you will not find many governments which say so.
In terms of international law, the distinction you're drawing between China and the PRC is irrelevant. Legally speaking, Taiwan was recognized as part of China. The fact that there was a revolution in China does not change that, legally speaking.
If such a principle were to be accepted, that a country's territory is called into question every time there's a revolution, it would open a Pandora's box.
Recognizing Taiwan as a formally independent state would be a major step, and it would open up all sorts of previously settled questions about what national sovereignty means.
> you will not find many governments which say so
You will find almost no governments that dispute it. Again, recognizing the formal independence of a territory that has been internationally recognized as part of China would be a major break with previous conceptions of national sovereignty.
There is no legal distinction between the PRC and China. The PRC is China on the international stage.
As far as I know, no country makes a distinction between China and the state that runs it. There is a handful of countries in the world that consider the ROC (i.e., Taiwan) to be the true government of China - countries such as the Vatican City and the Marshall Islands. As I understand it, the Vatican still recognizes the ROC because that's a negotiating chip it can play in its dispute with the PRC over how bishops are named in China.
There are a handful of countries which do still recognize the ROC as the legal government of China. It has gotten smaller as China has bought many out over the last few decade. So, yes, there is a legal distinction depending on who you ask.
Yes. The governments of the world switched recognition from the Republic of China to the People's Republic of China, and transferred "China's" UN Security Council seat to the PRC.
> However, it seems clear that at least most western countries see Taiwan as its own country in practice.
They maintain informal ties, but not formal diplomatic ties. Even the PRC has informal ties with the ROC.
> surprised to hear that Taiwan isn't supposed to be its own country
It's perhaps surprising, given Taiwan's de facto independence, but legally, it's not that surprising. Taiwan was a part of China, and it's difficult to define a point in time at which it ceased to be so. Both the ROC and PRC agreed that Taiwan was part of China for decades after the end of the civil war. The Taiwanese independence movement, which has become much stronger over the last 20 years, has changed sentiment in Taiwan itself. However, it would be a major step for other countries to decide that Taiwan no longer legally belongs to China.