Add NonNull pattern types #142339

oli-obk · 2025-06-11T07:10:30Z

These are the final piece missing for

Start using pattern types in libcore #136006

We cannot use the previous scheme of using an integer range for raw pointers, as we're not just changing the layout of raw pointers anymore, but also the type representation. And we can't represent "any provenance or NonZero" natively as patterns. So I created a new !null pattern. Since this is all unstable representation stuff for replacing rustc_layout_scalar_range_start with pattern types, the divergence from normal patterns is fine, especially since T-lang seems interested in exploring general negation patterns

r? @BoxyUwU

rustbot · 2025-06-11T07:10:36Z

Some changes occurred to the CTFE machinery

cc @RalfJung, @oli-obk, @lcnr

changes to the core type system

cc @compiler-errors, @lcnr

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

HIR ty lowering was modified

cc @fmease

Some changes occurred in compiler/rustc_codegen_cranelift

cc @bjorn3

Some changes occurred to MIR optimizations

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Some changes occurred to the CTFE / Miri interpreter

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The Miri subtree was changed

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Some changes occurred in src/tools/rustfmt

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changes to the core type system

cc @compiler-errors, @lcnr

Some changes occurred in compiler/rustc_codegen_ssa

cc @WaffleLapkin

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

rustbot · 2025-06-17T15:08:52Z

These commits modify the library/Cargo.lock file. Unintentional changes to library/Cargo.lock can be introduced when switching branches and rebasing PRs.

If this was unintentional then you should revert the changes before this PR is merged.
Otherwise, you can ignore this comment.

bors · 2025-07-04T18:50:49Z

☔ The latest upstream changes (presumably #143434) made this pull request unmergeable. Please resolve the merge conflicts.

bors · 2025-07-07T18:13:14Z

☔ The latest upstream changes (presumably #143582) made this pull request unmergeable. Please resolve the merge conflicts.

rustbot · 2025-07-08T07:15:14Z

This PR changes Stable MIR

cc @oli-obk, @celinval, @ouz-a

bors · 2025-07-14T20:43:56Z

☔ The latest upstream changes (presumably #143934) made this pull request unmergeable. Please resolve the merge conflicts.

rustbot · 2025-07-15T08:33:00Z

This PR changes rustc_public

cc @oli-obk, @celinval, @ouz-a

BoxyUwU · 2025-09-24T15:17:07Z

compiler/rustc_ty_utils/src/layout.rs

+                        // Make wide pointer pattern types contain only a single field
+                        // of the wide pointer type itself.
+                        layout.fields = FieldsShape::Arbitrary {
+                            offsets: [Size::ZERO].into_iter().collect(),
+                            memory_index: [0].into_iter().collect(),
+                        }


don't understand what this is doing/why we're inventing a field. also this applies to thin pointers too :3

I was encountering annoying to handle situations in various places (like const validation) where I had to duplicate the logic for pointers (wide or thin) on pattern types, because the pattern types directly contained all the information. Now that the pattern types "wrap" the pointer type, all the normal pointer logic simply runs after recursively walking the pattern type's layout. So this makes everything else more robutst, even if technically not necessary

I edited the comment to clarify this

talked about this sync. we think layout of all pattern types should do this "has a field" thing rather than it being !null pattern types of pointers specifically

bors · 2025-10-16T06:15:07Z

☔ The latest upstream changes (presumably #146221) made this pull request unmergeable. Please resolve the merge conflicts.

rustbot · 2025-10-21T09:52:34Z

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

oli-obk · 2025-10-21T18:54:35Z

@bors r=BoxyUwU

bors · 2025-10-21T18:54:37Z

📌 Commit 375899c has been approved by BoxyUwU

It is now in the queue for this repository.

Rollup of 7 pull requests Successful merges: - #141445 (Add `FromIterator` impls for `ascii::Char`s to `String`s) - #142339 (Add NonNull pattern types) - #147768 (Code refactoring on hir report_no_match_method_error) - #147788 (const Cell methods) - #147932 (Create UTF-8 version of `OsStr`/`OsString`) - #147933 (os_str: Make platform docs more consistent) - #147948 (PassWrapper: Access GlobalValueSummaryInfo::SummaryList via getter for LLVM 22+) r? `@ghost` `@rustbot` modify labels: rollup

Rollup of 7 pull requests Successful merges: - rust-lang/rust#141445 (Add `FromIterator` impls for `ascii::Char`s to `String`s) - rust-lang/rust#142339 (Add NonNull pattern types) - rust-lang/rust#147768 (Code refactoring on hir report_no_match_method_error) - rust-lang/rust#147788 (const Cell methods) - rust-lang/rust#147932 (Create UTF-8 version of `OsStr`/`OsString`) - rust-lang/rust#147933 (os_str: Make platform docs more consistent) - rust-lang/rust#147948 (PassWrapper: Access GlobalValueSummaryInfo::SummaryList via getter for LLVM 22+) r? `@ghost` `@rustbot` modify labels: rollup

RalfJung · 2025-10-23T06:10:36Z

src/tools/miri/tests/pass/pattern-types.rs

+
+fn main() {
+    unsafe {
+        let _: NonNull<dyn Trait> = NonNull { pointer: transmute(&mut () as *mut dyn Trait) };


@oli-obk the unsizing here happens before pattern types are even involved, doesn't it? It happens during the &mut () as *mut dyn Trait. So I don't see how this tests anything about pattern type unsizing.

It's not about unsizing pattern types, but just about the existence of unsized pattern types. I don't think unsizing pattern types works but I'll add some tests

NonNull<dyn Trait> is a sized type, so I don't think there is an unsized pattern type in this example.

No i mean we can't do NonNull<()> unsizing to NonNull<dyn Trait>. The pointer is obviously sized. Am I using the terminology wrong again? 😅

I was just nitpicking about this part:

but just about the existence of unsized pattern types

This is more like, "pattern types for wide pointers" or so?

RalfJung · 2025-10-23T06:12:02Z

src/tools/miri/tests/pass/pattern-types.rs

I'm a bit confused by this test -- it only covers is !null pattern types, but the name is much more general than that? Would be good to have a comment explaining the point of this. The commit message says something about "unsizing pattern types with pointer base"?

rustbot assigned BoxyUwU Jun 11, 2025

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Pattern types have their base type as a field

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oli-obk added 2 commits October 21, 2025 11:22

Add not-null pointer patterns to pattern types

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Allow unsizing pattern types with pointer base

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matthiaskrgr mentioned this pull request Oct 22, 2025

Rollup of 7 pull requests #147957

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bors merged commit f6d324f into rust-lang:master Oct 22, 2025
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Add NonNull pattern types #142339

Add NonNull pattern types #142339

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