Stall auto trait assembly in new solver for int/float vars #109752

compiler-errors · 2023-03-30T02:34:33Z

Make sure that we don't match int/float vars against all manual auto trait impls due to this check:

rust/compiler/rustc_trait_selection/src/solve/trait_goals.rs

Lines 151 to 169 in 2fb0e8d

    
           // This differs from the current stable behavior and 
        
           // fixes #84857. Due to breakage found via crater, we 
        
           // currently instead lint patterns which can be used to 
        
           // exploit this unsoundness on stable, see #93367 for 
        
           // more details. 
        
           // 
        
           // Using `TreatProjections::NextSolverLookup` is fine here because 
        
           // `instantiate_constituent_tys_for_auto_trait` returns nothing for 
        
           // projection types anyways. So it doesn't really matter what we do 
        
           // here, and this is faster. 
        
           if let Some(def_id) = ecx.tcx().find_map_relevant_impl( 
        
               goal.predicate.def_id(), 
        
               goal.predicate.self_ty(), 
        
               TreatProjections::NextSolverLookup, 
        
               Some, 
        
           ) { 
        
               debug!(?def_id, ?goal, "disqualified auto-trait implementation"); 
        
               return Err(NoSolution); 
        
           }

Since find_map_relevant_impl treats all impls as candidates for int/float vars, due to the way that fast_reject::simplify_type works.

This fixes compiler-errors/next-solver-hir-issues#11.

r? @lcnr

rustbot · 2023-03-30T02:34:41Z

Some changes occurred to the core trait solver

cc @rust-lang/initiative-trait-system-refactor

lcnr

can you instead make this is a match on goal.predicate.self_ty().kind() and only call find_map_relevant_impl for actual rigid types, already a bit worried about how this handles alias types and what not.

r=me afterwards

compiler-errors · 2023-04-03T23:39:50Z

I'd actually probably like a re-review on this, just in case I'm implementing what @lcnr wanted.

@rustbot ready

lcnr · 2023-04-10T06:36:56Z

@bors r+ rollup

bors · 2023-04-10T06:36:58Z

📌 Commit 0b7cae532dff143bbf722ff92bfe1b65c4227f53 has been approved by lcnr

It is now in the queue for this repository.

Rollup of 6 pull requests Successful merges: - rust-lang#109724 (prioritize param env candidates if they don't guide type inference) - rust-lang#110021 (Fix a couple ICEs in the new `CastKind::Transmute` code) - rust-lang#110044 (Avoid some manual slice length calculation) - rust-lang#110115 (compiletest: Use remap-path-prefix only in CI) - rust-lang#110121 (Fix `x check --stage 1` when download-rustc is enabled) - rust-lang#110124 (Some clippy fixes in the compiler) Failed merges: - rust-lang#109752 (Stall auto trait assembly in new solver for int/float vars) r? `@ghost` `@rustbot` modify labels: rollup

bors · 2023-04-10T12:33:30Z

☔ The latest upstream changes (presumably #110137) made this pull request unmergeable. Please resolve the merge conflicts.

compiler-errors · 2023-04-10T16:43:06Z

@bors r=lcnr

bors · 2023-04-10T16:43:08Z

📌 Commit 8d2dbba has been approved by lcnr

It is now in the queue for this repository.

…uto-trait-for-num-var, r=lcnr Stall auto trait assembly in new solver for int/float vars Make sure that we don't match int/float vars against *all* manual auto trait impls due to this check: https://github.com/rust-lang/rust/blob/2fb0e8d162a021f8a795fb603f5d8c0017855160/compiler/rustc_trait_selection/src/solve/trait_goals.rs#L151-L169 Since `find_map_relevant_impl` treats all impls as candidates for int/float vars, due to the way that `fast_reject::simplify_type` works. This fixes compiler-errors/next-solver-hir-issues#11. r? `@lcnr`

Rollup of 8 pull requests Successful merges: - rust-lang#109527 (Set up standard library path substitution in rust-gdb and gdbgui) - rust-lang#109752 (Stall auto trait assembly in new solver for int/float vars) - rust-lang#109860 (Add support for RISC-V relax target feature) - rust-lang#109923 (Update `error [E0449]: unnecessary visibility qualifier` to be more clear) - rust-lang#110070 (The `wrapping_neg` example for unsigned types shouldn't use `i8`) - rust-lang#110146 (fix(doc): do not parse inline when output is json for external crate) - rust-lang#110147 (Add regression test for rust-lang#104916) - rust-lang#110149 (Update books) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup

rustbot assigned lcnr Mar 30, 2023

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. WG-trait-system-refactor The Rustc Trait System Refactor Initiative (-Znext-solver) labels Mar 30, 2023

lcnr reviewed Mar 30, 2023

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lcnr added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 31, 2023

rust-cloud-vms bot force-pushed the new-solver-stall-auto-trait-for-num-var branch 2 times, most recently from ea14918 to 0b7cae5 Compare April 3, 2023 23:39

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Apr 3, 2023

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Apr 10, 2023

Dylan-DPC mentioned this pull request Apr 10, 2023

Rollup of 6 pull requests #110137

Merged

bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Apr 10, 2023

Stall auto-trait assembly for int/float vars in new solver

8d2dbba

rust-cloud-vms bot force-pushed the new-solver-stall-auto-trait-for-num-var branch from 0b7cae5 to 8d2dbba Compare April 10, 2023 16:00

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Apr 10, 2023

JohnTitor mentioned this pull request Apr 11, 2023

Rollup of 9 pull requests #110167

Closed

JohnTitor mentioned this pull request Apr 11, 2023

Rollup of 8 pull requests #110170

Merged

bors merged commit a69cc45 into rust-lang:master Apr 11, 2023

rustbot added this to the 1.70.0 milestone Apr 11, 2023

compiler-errors deleted the new-solver-stall-auto-trait-for-num-var branch August 11, 2023 20:10

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Stall auto trait assembly in new solver for int/float vars #109752

Stall auto trait assembly in new solver for int/float vars #109752

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	// This differs from the current stable behavior and
	// fixes #84857. Due to breakage found via crater, we
	// currently instead lint patterns which can be used to
	// exploit this unsoundness on stable, see #93367 for
	// more details.
	//
	// Using `TreatProjections::NextSolverLookup` is fine here because
	// `instantiate_constituent_tys_for_auto_trait` returns nothing for
	// projection types anyways. So it doesn't really matter what we do
	// here, and this is faster.
	if let Some(def_id) = ecx.tcx().find_map_relevant_impl(
	goal.predicate.def_id(),
	goal.predicate.self_ty(),
	TreatProjections::NextSolverLookup,
	Some,
	) {
	debug!(?def_id, ?goal, "disqualified auto-trait implementation");
	return Err(NoSolution);
	}

Stall auto trait assembly in new solver for int/float vars #109752

Stall auto trait assembly in new solver for int/float vars #109752

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