viperproject/silicon

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Symbolic-execution-based verifier for the Viper intermediate verification language.

Stars: 145
Forks: 42
Open beginner issues: 0
Indexed issues: 113
Avg merge: 2d 14h
Merged PRs (30d): 3

Dominant language: Scala
License: MPL-2.0
Last GitHub push: Sep 14, 2026
Latest indexed: Sep 20, 2026
Contributing guide: No contributing guide
Code of conduct: No code of conduct
Beginner labels: No beginner labels indexed

Beginner friendly Everything

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113 open issues indexed

quantifiedExp does not apply its `ignore` parameter, unlike `quantified` Open

Difficulty 3/5 1-2 days Newbie friendliness 68/100

viperproject/silicon#1006 · Opened Sep 9, 2026
Recursive function plus quantifier that triggers on the function results in matching loop Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

viperproject/silicon#1004 · Opened Aug 25, 2026
Unclear error message when injectivity check fails in a subexpression Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

viperproject/silicon#997 · Opened Aug 10, 2026
Forward goto after variable declaration causes crash Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#991 · Opened Jul 10, 2026
Doing bitvector work in cvc5 puts the solver in a broken state Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

viperproject/silicon#990 · Opened Jul 10, 2026
Conjunction of abstract functions is not able to be asserted Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

viperproject/silicon#989 · 1 comment · Opened Jul 10, 2026
Wands are not checked for self-framingness Open

magic-wands

Difficulty 4/5 3-5 days Newbie friendliness 48/100

viperproject/silicon#974 · Opened May 7, 2026
Asserting after assuming quantifier with heap-dependent trigger fails Open

bug incompleteness quantified-permissions

Difficulty 4/5 3-5 days Newbie friendliness 38/100

viperproject/silicon#959 · 2 comments · Opened Jan 15, 2026
A potential bug in how Silicon handles loop invariant Open

Difficulty 4/5 3-5 days Newbie friendliness 38/100

viperproject/silicon#957 · 2 comments · Opened Dec 9, 2025
Internal function preconditions not assumed in wand-related scenario Open

incompleteness

viperproject/silicon#951 · 1 assignee · Opened Nov 24, 2025
Something is wrong with predicate triggers for functions Open

unsoundness

viperproject/silicon#925 · 1 comment · 1 assignee · Opened May 20, 2025
Information following from field access receiver not known when checking for permission Open

incompleteness

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#912 · 1 comment · 1 reaction · Opened Mar 20, 2025
NumberFormatException when Enabling Counterexamples Open

Difficulty 3/5 1-2 days Newbie friendliness 42/100

viperproject/silicon#902 · Opened Mar 3, 2025
Method only verifies with --useOldAxiomatization Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#855 · Opened Jun 19, 2024
Lots of tests fail with --conditionalizePermissions Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

viperproject/silicon#851 · Opened Jun 13, 2024
Weird behavior if WorkerBorrowingForkJoinWorkerThread.onStart throws an InterruptedException Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

viperproject/silicon#850 · Opened Jun 13, 2024
Multiple quantifiers to memory locations of same type Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#831 · 4 comments · Opened Apr 23, 2024
Tests non-deterministically time out Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#801 · Opened Feb 7, 2024
Unsound axiom not considered when domain not used Open

viperproject/silicon#793 · 1 comment · 1 assignee · Opened Jan 4, 2024
Strange output when reporting quantifier instantiations using newer Z3 versions Open

Difficulty 3/5 1-2 days Newbie friendliness 42/100

viperproject/silicon#786 · 1 comment · Opened Dec 15, 2023
Efficient solver initialization by cloning Open

performance

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#731 · 10 comments · Opened Jun 9, 2023
Avoiding double QI across (pop) Open

performance

Difficulty 5/5 Over a week Newbie friendliness 30/100

viperproject/silicon#702 · 3 comments · 1 reaction · Opened Apr 6, 2023
Triggers silently ignored/replaced Open

functions

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#661 · 8 comments · Opened Nov 21, 2022
Unsoundness of old expressions in magic wands in postconditions Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#656 · 5 comments · Opened Nov 8, 2022
Strange filename ending `.silver` Open

Difficulty 1/5 Under an hour Newbie friendliness 58/100

viperproject/silicon#647 · Opened Oct 14, 2022
Repeating easy precondition increases verification time Open

Difficulty 5/5 Over a week Newbie friendliness 28/100

viperproject/silicon#637 · 8 comments · Opened Sep 1, 2022
Function body is not available while checking the well-formedness of the postcondition Open

functions incompleteness

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#624 · 2 comments · Opened Jun 29, 2022
Incompleteness due to multiple different representation of state snapshots Open

incompleteness

Difficulty 5/5 Over a week Newbie friendliness 35/100

viperproject/silicon#623 · 2 comments · Opened Jun 27, 2022
z3 trace-file-name Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#618 · Opened Jun 2, 2022
Silicon cannot find z3 in PATH Open

Difficulty 2/5 1-3 hours Newbie friendliness 55/100

viperproject/silicon#617 · 1 reaction · Opened Jun 2, 2022
Reference non-aliasing only assertable after a fold, but not before Open

bug incompleteness

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#616 · Opened May 19, 2022
Injectivity check not performed inside a magic wand Open

bug magic-wands quantified-permissions

Difficulty 4/5 3-5 days Newbie friendliness 38/100

viperproject/silicon#614 · Opened May 16, 2022
Error deduplication + NoPosition Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

viperproject/silicon#613 · 6 comments · Opened May 12, 2022
Loop invariant not preserved when unfolding inside a quantifier Open

incompleteness

Difficulty 5/5 Over a week Newbie friendliness 25/100

viperproject/silicon#611 · 2 comments · Opened Apr 28, 2022
enabling MBQI causes unsat after sortwrappers Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#600 · 6 comments · Opened Feb 17, 2022
Report inferred triggers Open

enhancement

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#586 · 3 comments · Opened Jan 7, 2022
Memory leaks in Silicon Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#579 · 3 comments · Opened Nov 3, 2021
Unsound package algorithm for magic wands Open

bug critical magic-wands

Difficulty 5/5 Over a week Newbie friendliness 35/100

viperproject/silicon#573 · Opened Jul 28, 2021
Quantifier-related incompleteness Open

incompleteness

Difficulty 4/5 3-5 days Newbie friendliness 25/100

viperproject/silicon#567 · Opened Jul 14, 2021
Remove consumeexact & constrainingARPs Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

viperproject/silicon#563 · 1 comment · Opened Jul 8, 2021
List of test cases that fail using more complete exhale Open

more-complete-exhale

Difficulty 4/5 3-5 days Newbie friendliness 25/100

viperproject/silicon#557 · 2 comments · Opened Jun 25, 2021
Silicon doesn't verify QPWands.vpr Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#551 · Opened May 6, 2021
Silicon doesn't verify examples/list_insert_tmp.vpr Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#550 · Opened May 6, 2021
Possibly faulty "Contract might not be well-formed error" Open

incompleteness

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#537 · 5 comments · Opened Mar 27, 2021
Cannot link expression to old version with quantified permissions Open

Difficulty 5/5 Over a week Newbie friendliness 15/100

viperproject/silicon#536 · 2 comments · Opened Mar 26, 2021
Unexpected output of Z3 causes Silicon to crash Open

z3

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#535 · 4 comments · Opened Mar 23, 2021
Avoid linear scan in isKnownToBeTrue Open

enhancement performance

Difficulty 3/5 1-2 days Newbie friendliness 42/100

viperproject/silicon#522 · 1 comment · Opened Nov 11, 2020
Instability in test case, which disappears when removing unrelated program elements Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

viperproject/silicon#515 · 5 comments · Opened Aug 30, 2020
Retire state consolidation hack Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 25/100

viperproject/silicon#510 · Opened Jul 31, 2020
SymbExLogger provides incorrect outputs Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

viperproject/silicon#507 · 1 comment · Opened Jul 27, 2020

viperproject/silicon

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