[Mlir-commits] [mlir] [mlir] Support better printing for mutually recursive types (PR #112160)

[River Riddle]

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@@ -525,7 +529,7 @@ void TestRecursiveAliasType::print(AsmPrinter &printer) const {
       printer.tryStartCyclicPrint(*this);
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River707 wrote:

> used to signal that you must print a forward declaration, whereas this new check signals that you may print a forward declaration

I think I'm missing the distinction here. I don't see why we care to differentiate these two, why would you not print the elided form if you could? My expectation for the parser/printer API for recursive things would be: If the printer tells you that it's okay to elide, you do. In the parser you just check whether you're parsing the elided or non-elided form. As an aside, for this stuff I'd err on changing the contract of the current cyclic printing/parsing logic, it has ~4 uses in tree (2 of which are in tests), I'd hope we can just continue to evolve the recursive support (and not add more constructs).

https://github.com/llvm/llvm-project/pull/112160