Fix parsing logic in proc_macro::quote

[moatom]

Fix #140238

[rustbot]

r? @petrochenkov

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[moatom]

r? @tgross35

[rustbot]

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[rust-log-analyzer]

The job aarch64-gnu-llvm-20-1 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

---- [ui] tests/ui/proc-macro/quote/basic.rs stdout ----

error: auxiliary build of /checkout/tests/ui/proc-macro/quote/auxiliary/basic.rs failed to compile: 
status: exit status: 1
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/proc-macro/quote/auxiliary/basic.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2" "--target=aarch64-unknown-linux-gnu" "--check-cfg" "cfg(test,FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/proc-macro/quote/basic/auxiliary" "-A" "internal_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/aarch64-unknown-linux-gnu/native/rust-test-helpers" "--crate-type" "proc-macro" "--extern" "proc_macro" "-L" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/proc-macro/quote/basic/auxiliary"
stdout: none
--- stderr -------------------------------
error[E0425]: cannot find value `j` in this scope
##[error]  --> /checkout/tests/ui/proc-macro/quote/auxiliary/basic.rs:66:35
   |
LL |     let tokens = quote!($$ j $($$ j $iter)*);
   |                                   ^ help: a unit struct with a similar name exists: `X`
...
LL | struct X;
   | --------- similarly named unit struct `X` defined here

error[E0282]: type annotations needed
##[error]  --> /checkout/tests/ui/proc-macro/quote/auxiliary/basic.rs:66:35
   |
LL |     let tokens = quote!($$ j $($$ j $iter)*);
   |                                   ^ cannot infer type

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0282, E0425.
For more information about an error, try `rustc --explain E0282`.

[tgross35]

David knows this much better than I do

r? @dtolnay

[moatom]

@bors r+

[bors]

@moatom: 🔑 Insufficient privileges: Not in reviewers