Skip to content

lint: Fix ICE on error_mark_node in unused variable linter#4438

Merged
P-E-P merged 1 commit intoRust-GCC:masterfrom
Pasta-coder:issue-3910
Apr 13, 2026
Merged

lint: Fix ICE on error_mark_node in unused variable linter#4438
P-E-P merged 1 commit intoRust-GCC:masterfrom
Pasta-coder:issue-3910

Conversation

@Pasta-coder
Copy link
Copy Markdown
Contributor

@Pasta-coder Pasta-coder commented Feb 14, 2026

Fixes #3910

powerboat9
powerboat9 reviewed Feb 14, 2026
View reviewed changes
Comment thread gcc/rust/checks/lints/rust-lint-unused-var.cc Outdated
@philberty
Copy link
Copy Markdown
Member

philberty commented Feb 16, 2026

actually this is hiding a code gen bug it shouldnt merge this unless we understand why an error mark node has crept into the IR

@Pasta-coder
Copy link
Copy Markdown
Contributor Author

Pasta-coder commented Feb 16, 2026

Because const generics aren't fully lowered yet, compile_constant_item returns an error_mark_node. However, the backend blindly pushes this into the context via ctx->insert_const_decl inside rust-compile-implitem.cc and rust-compile-item.cc without checking if the compilation actually succeeded.

I will instead add an if (const_expr != error_mark_node) guard right before the insert_const_decl calls in the backend. I'll update the PR with this fix shortly!

@Pasta-coder Pasta-coder force-pushed the issue-3910 branch 2 times, most recently from 91167e1 to 532c867 Compare February 16, 2026 09:47
philberty
philberty approved these changes Feb 25, 2026
View reviewed changes
Copy link
Copy Markdown
Member

@philberty philberty left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

LGTM

@Pasta-coder
Copy link
Copy Markdown
Contributor Author

Pasta-coder commented Mar 11, 2026

@P-E-P can we merge this ?

P-E-P
P-E-P reviewed Mar 25, 2026
View reviewed changes
Comment thread gcc/testsuite/rust/compile/issue-3910.rs Outdated
@Pasta-coder
backend: Prevent error_mark_node from leaking into const context
51f3dc1 
Fixes Rust-GCC#3910

gcc/rust/ChangeLog:

	* backend/rust-compile-item.cc (CompileItem::visit): Do not insert
	const_expr into the context if it is an error_mark_node.
	* backend/rust-compile-implitem.cc (CompileTraitItem::visit): Likewise.

gcc/testsuite/ChangeLog:

	* rust/compile/issue-3910.rs: New test.

Signed-off-by: jayant chauhan <0001jayant@gmail.com>
@Pasta-coder
Copy link
Copy Markdown
Contributor Author

Pasta-coder commented Apr 12, 2026

cc @P-E-P

@P-E-P P-E-P added this pull request to the merge queue Apr 13, 2026
Merged via the queue into Rust-GCC:master with commit f1e56c4 Apr 13, 2026
12 checks passed
@Pasta-coder Pasta-coder deleted the issue-3910 branch April 13, 2026 22:18
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

@powerboat9 powerboat9 powerboat9 left review comments

@philberty philberty philberty approved these changes

@P-E-P P-E-P P-E-P approved these changes

@CohenArthur CohenArthur Awaiting requested review from CohenArthur

Assignees

No one assigned

Labels

None yet

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

ICE in check_decl, at rust/checks/lints/rust-lint-unused-var.cc:28

4 participants

@Pasta-coder @philberty @powerboat9 @P-E-P