Initialise DeclCtx field with nullptr.

Relocate function and fix comment for consistency.

Rebase to head.

Formatting fixes.

Update DeclCtx when pushing/popping calls.

Removed unused imports in SolverTest.cpp

Address comments.

Address comment on renaming parameter. Add const qualifier to BoolValue input to debugString.

Address comments: add used import, remove unused imports.

Change propagated from parent patch.

Move DebugStringGenerator class into anonymous namespace.

Remove unnecessary enum keyword.

Fix use after move.

Fix comment, remove unused import.

Address comments.

Address comments.

Address comments on renaming. Removed test fixture class, replacing TEST_F with TEST.

Use std::vector as input to debugString to maintain order stability of boolean constraints to enable testing. debugString which takes a llvm::DenseSet<BoolValue*> is now a wrapper around the logic applied to std::vector.

Minor fixes.

Extract recursion into boolean subvalues into separate statements to enforce order of evaluation.

Update CMakeList for DebugSupportTest.cpp

Remove decomposing declarations which are not available in llvm.

Replace std::optional with llvm::Optional

Fix comment.

Address comments.

Make scope resolution consistent (Solver:: instead of WatchedLiteralsSolver::).

Typo fix.

Address comments.

Add assert message.

Propagate change from parent patch.

Add macro for only testing asserts in debug mode.

Fix comment.

Assert that user does not try to substitute true/false booleans.

Address comments.

Fix comment.

Address comments - add example to buildAndSubstituteFlowCondition doc comment, add tests for atomic and negated flow condition.

Propagate change from parent patch.

Rename checkUnsatisfiable to isUnsatisfiable

Address comments.

Rename createIff to getOrCreateIff based on change in parent patch.

Address comments - rename createIff/Implication to getOrCreateIff/Implication and add tests for these functions

Fix comment.

@xazax.hun

Could you elaborate on why do we need this?

We are currently working on a pointer nullability analysis here: https://github.com/google/crubit/tree/main/nullability_verification.
One of the things we are trying to do is to check if the flow condition is independent of a variable, done by checking if the formula regardless if the variable is substituted to true or false - requiring buildAndSubstituteFlowCondition.

Address comments.

Address comments.