Commit d032119

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Don't fold in Instantiate when there's nothing to fold

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Original file line number	Diff line number	Diff line change
`@@ -622,6 +622,17 @@ impl<I: Interner, T: TypeFoldable<I>> ty::EarlyBinder<I, T> {`
`622`	`622`	`where`
`623`	`623`	`A: SliceLike<Item = I::GenericArg>,`
`624`	`624`	`{`
	`625`	`+ // Nothing to fold, so let's avoid visiting things and possibly re-hashing/equating`
	`626`	`+ // them when interning. Perf testing found this to be a modest improvement.`
	`627`	`+ // See: <https://github.com/rust-lang/rust/pull/142317>`
	`628`	`+ if args.is_empty() {`
	`629`	`+ assert!(`
	`630`	`+ !self.value.has_param(),`
	`631`	`+ "{:?} has parameters, but no args were provided in instantiate",`
	`632`	`+ self.value,`
	`633`	`+ );`
	`634`	`+ return self.value;`
	`635`	`+ }`
`625`	`636`	`let mut folder = ArgFolder { cx, args: args.as_slice(), binders_passed: 0 };`
`626`	`637`	`self.value.fold_with(&mut folder)`
`627`	`638`	`}`

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