Fix three constructor-discovery ICEs from the crates.io sweep - #4725
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Surfaced by a top-500 crates.io autoharness sweep (12 crates affected): 1. Items with their own early-bound lifetimes (AtomicU8::from_ptr<'a>) were resolved with the ADT args only, panicking on the arity mismatch (brotli, sharded-slab). 2. Lifetime-parameterized impls place lifetimes anywhere in the generics order (impl<'h> Searcher<'h> in regex-automata; also gimli, redox_syscall, arc-swap, clap_builder, event-listener, crypto-bigint), so appending erased lifetimes is not enough: build the argument list positionally against the item's full parent+own generics, rejecting the constructor when counts or kinds do not fit (rustc's instantiation panics on kind mismatches rather than returning Err). 3. Constructor arguments carrying escaping late-bound regions inside ADTs (BorrowedFd<'_> in async-io, js-sys, quinn-udp, wasm-bindgen) panicked the trait solver's dummy-binder wrap; such arguments are not generatable, so reject the candidate up front. The constructor regression test gains all three shapes. Co-authored-by: Kiro <kiro-agent@users.noreply.github.com>
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Stacked on #4717 (
--constructor-args); only the last commit is new. Marked draft until #4717 merges.A top-500 crates.io autoharness sweep (tracking #3832) ICEd in constructor discovery on 12 crates; three root causes:
AtomicU8::from_ptr<'a>-style constructors were resolved with the ADT args only — arity mismatch panic.impl<'h> Searcher<'h>places the lifetime first, so appending erased lifetimes is insufficient — the argument list is now built positionally against the item's full parent+own generics, rejecting shape mismatches up front (rustc's instantiation panics on kind mismatches rather than returningErr).BorrowedFd<'_>-style arguments read from a skipped fn-sig binder panicked the trait solver's dummy-binder wrap; such candidates are rejected as non-generatable.All 12 crates verified clean with this branch. The constructor regression test gains all three shapes.
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