C#: Replace CFG with the shared implementation

[aschackmull]

This PR migrates the C# libraries to use the new shared CFG library.

Several queries are impacted, but overall I'd say that it's generally increased precision.

The first few commits are preliminary setup tweaks. Then "C#: Replace CFG." is the big commit that deletes the old CFG and puts in the new instantiation of the shared libraries. And the several following commits then deal primarily with qltest fallout.

[Copilot]

Pull request overview

Migrates the C# CodeQL libraries from the legacy C#-specific CFG to the shared control-flow graph implementation, updating affected queries and tests to the new node/basic-block APIs and semantics.

Changes:

• Extend the shared CFG AST signature/support (e.g., goto, throw-as-expression, compound assignments, pattern matching) and align Java’s CFG wrapper to it.
• Update C# libraries/queries to use shared ControlFlowNode/BasicBlock types and shared CFG utilities (incl. dispatch/SSA/dataflow integrations).
• Update/refresh C# library tests and expected outputs to match the new CFG structure and precision changes.

Show a summary per file

File	Description
shared/controlflow/codeql/controlflow/ControlFlowGraph.qll	Extends shared CFG AST signature and CFG construction logic (goto/throw/assignments/pattern-match, dominance utilities, consistency helpers).
java/ql/lib/semmle/code/java/ControlFlowGraph.qll	Adapts Java CFG wrapper to the updated shared CFG AST signature.
csharp/ql/test/library-tests/standalone/controlflow/cfg.ql	Updates test query to use ControlFlowNode instead of legacy CFG node types.
csharp/ql/test/library-tests/standalone/controlflow/cfg.expected	Updates expected CFG edge output for the shared CFG structure.
csharp/ql/test/library-tests/security/dataflow/flowsources/StoredFlowSources.expected	Updates expected results reflecting CFG/dataflow precision changes.
csharp/ql/test/library-tests/obinit/ObInit.ql	Updates object-initializer CFG test to new node/successor APIs.
csharp/ql/test/library-tests/obinit/ObInit.expected	Updates expected output for shared CFG.
csharp/ql/test/library-tests/goto/Goto1.ql	Updates goto CFG test to use getASuccessor(t) on ControlFlowNode.
csharp/ql/test/library-tests/goto/Goto1.expected	Updates expected output for shared CFG and goto edges.
csharp/ql/test/library-tests/dataflow/ssa/SSAPhiRead.ql	Updates SSA phi-read tests to shared BasicBlock / ControlFlowNode types.
csharp/ql/test/library-tests/dataflow/ssa/SSAPhiRead.expected	Updates expected SSA outputs.
csharp/ql/test/library-tests/dataflow/ssa/SsaDefElement.expected	Updates expected SSA definition/phi placement outputs.
csharp/ql/test/library-tests/dataflow/ssa-large/countssa.ql	Updates SSA-large test to shared BasicBlock.
csharp/ql/test/library-tests/dataflow/ssa-large/countssa.expected	Updates expected counts after CFG/SSA changes.
csharp/ql/test/library-tests/dataflow/signanalysis/SignAnalysis.ql	Updates sign analysis test to ControlFlowNodes::ExprNode naming.
csharp/ql/test/library-tests/dataflow/signanalysis/SignAnalysis.expected	Updates expected sign analysis results.
csharp/ql/test/library-tests/dataflow/signanalysis/MissingSign.ql	Updates missing-sign test to new control-flow node classes.
csharp/ql/test/library-tests/dataflow/modulusanalysis/ModulusAnalysis.ql	Updates modulus analysis test to new control-flow node classes.
csharp/ql/test/library-tests/dataflow/modulusanalysis/ModulusAnalysis.expected	Updates expected modulus analysis output.
csharp/ql/test/library-tests/dataflow/defuse/useUseEquivalence.ql	Updates def-use equivalence tests to shared CFG/BasicBlock traversal APIs.
csharp/ql/test/library-tests/dataflow/defuse/parameterUseEquivalence.ql	Updates parameter reachability test to shared ControlFlowNode.
csharp/ql/test/library-tests/dataflow/defuse/defUseEquivalence.ql	Updates def-use reachability test to shared ControlFlowNode.
csharp/ql/test/library-tests/dataflow/call-sensitivity/CallSensitivityFlow.expected	Updates expected call-sensitivity output after CFG/dataflow changes.
csharp/ql/test/library-tests/csharp8/UsingControlFlow.ql	Updates CFG edge selection in using-declarations test to new successor API.
csharp/ql/test/library-tests/csharp8/UsingControlFlow.expected	Updates expected CFG edges for using-declarations.
csharp/ql/test/library-tests/csharp8/switchstmtctrlflow.ql	Updates switch-statement CFG edge test to new successor API.
csharp/ql/test/library-tests/csharp8/switchexprcontrolflow.ql	Updates switch-expression CFG edge test to new successor API.
csharp/ql/test/library-tests/csharp8/NullCoalescingControlFlow.ql	Updates null-coalescing CFG test to new successor API.
csharp/ql/test/library-tests/csharp8/NullCoalescingControlFlow.expected	Updates expected CFG edges for null-coalescing (incl. ??= modeling).
csharp/ql/test/library-tests/csharp8/NullableRefTypes.ql	Updates nullable-ref CFG test to new node/successor API.
csharp/ql/test/library-tests/csharp8/NullableRefTypes.expected	Updates expected CFG output for nullable-ref tests.
csharp/ql/test/library-tests/csharp8/ispatternflow.ql	Updates pattern-flow CFG test to new successor API.
csharp/ql/test/library-tests/csharp7/LocalTaintFlow.expected	Updates expected local taint flow after CFG/dataflow changes.
csharp/ql/test/library-tests/csharp7/IsFlow.ql	Updates is-pattern/switch CFG edge test to new successor API.
csharp/ql/test/library-tests/csharp11/signAnalysis.ql	Updates C#11 sign analysis test to ControlFlowNodes::ExprNode.
csharp/ql/test/library-tests/controlflow/guards/Guards.cs	Adjusts guard test source comments to reflect new handling.
csharp/ql/test/library-tests/controlflow/guards/GuardedExpr.expected	Updates expected guarded-expression results.
csharp/ql/test/library-tests/controlflow/guards/GuardedControlFlowNode.expected	Updates expected guarded control-flow node results.
csharp/ql/test/library-tests/controlflow/guards/BooleanGuardedExpr.expected	Updates expected boolean-guard results.
csharp/ql/test/library-tests/controlflow/guards-large/GuardedExpr.expected	Updates expected results for stress/large guard suite.
csharp/ql/test/library-tests/controlflow/graph/Nodes.ql	Updates controlflow graph tests to shared CFG entrypoint/node mapping.
csharp/ql/test/library-tests/controlflow/graph/NodeGraph.ql	Switches test import to shared ControlFlow::TestOutput.
csharp/ql/test/library-tests/controlflow/graph/ExitElement.ql	Removes legacy exit-element test relying on old CFG internals.
csharp/ql/test/library-tests/controlflow/graph/EntryElement.ql	Re-implements “first node” selection using shared CFG traversal.
csharp/ql/test/library-tests/controlflow/graph/EnclosingCallable.ql	Updates basic-block enclosing callable accessor.
csharp/ql/test/library-tests/controlflow/graph/CONSISTENCY/CfgConsistency.expected	Removes legacy CFG consistency expected output.
csharp/ql/test/library-tests/controlflow/graph/Condition.ql	Updates condition-block and successor selection to shared CFG APIs.
csharp/ql/test/library-tests/controlflow/graph/Common.qll	Updates test helper classes to shared CFG node/basic-block types.
csharp/ql/src/Security Features/CWE-384/AbandonSession.ql	Updates control-flow stepping logic to shared node APIs (asExpr, typed successors).
csharp/ql/src/Performance/StringBuilderInLoop.ql	Updates loop-entry selection to shared CFG positioning (isBefore).
csharp/ql/src/Likely Bugs/UncheckedCastInEquals.ql	Reworks reachability logic to shared CFG nodes for parameter-access ordering.
csharp/ql/src/Likely Bugs/Statements/UseBraces.ql	Updates successor-statement search to shared node-to-stmt mapping (asStmt).
csharp/ql/src/Likely Bugs/NestedLoopsSameVariable.ql	Updates guard/exit-node selection using shared CFG node predicates.
csharp/ql/src/Concurrency/UnsynchronizedStaticAccess.ql	Updates “unlocked reachable” analysis to operate on shared BasicBlocks and node indices.
csharp/ql/src/Bad Practices/Control-Flow/ConstantCondition.ql	Updates constant-condition query input signature to shared BasicBlock.
csharp/ql/lib/semmle/code/csharp/security/dataflow/ConditionalBypassQuery.qll	Removes dependency on legacy BasicBlocks module.
csharp/ql/lib/semmle/code/csharp/exprs/Call.qll	Refines accessor-call static target handling (read vs write) for compound assignments.
csharp/ql/lib/semmle/code/csharp/ExprOrStmtParent.qll	Adjusts enclosing-body/callable parent relationships after CFG changes.
csharp/ql/lib/semmle/code/csharp/dispatch/Dispatch.qll	Adds control-flow-node access on dispatch calls; splits accessor calls into read/write variants.
csharp/ql/lib/semmle/code/csharp/dataflow/SSA.qll	Updates SSA definition/node mapping and BasicBlock typing; adjusts string formatting and element mapping.
csharp/ql/lib/semmle/code/csharp/dataflow/SignAnalysis.qll	Updates sign-analysis API signatures from legacy CFG nodes to shared ControlFlowNode.
csharp/ql/lib/semmle/code/csharp/dataflow/Nullness.qll	Updates nullness analysis to shared node types and asExpr() usage.
csharp/ql/lib/semmle/code/csharp/dataflow/internal/TaintTrackingPublic.qll	Replaces * closure with fastTC for local taint reachability (plus identity case).
csharp/ql/lib/semmle/code/csharp/dataflow/internal/SsaImpl.qll	Refactors SSA implementation to shared CFG (Cfg/BasicBlock/ControlFlowNode) and updated dispatch/call-graph integration.
csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/SsaUtils.qll	Updates range-analysis SSA utilities to ControlFlowNodes::ExprNode.
csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/SsaReadPositionSpecific.qll	Updates read-position ordering helpers to shared CFG constructs and new imports/aliases.
csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/SignAnalysisSpecific.qll	Updates range-analysis sign modeling to shared control-flow node classes.
csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/RangeUtils.qll	Updates range utilities to shared CFG types and node accessors.
csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/ModulusAnalysisSpecific.qll	Updates modulus-specific range modeling to shared node classes.
csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/ConstantUtils.qll	Updates constant utilities to shared ControlFlowNodes::ExprNode.
csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/BoundSpecific.qll	Updates bound modeling to shared ControlFlowNodes::ExprNode.
csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowPublic.qll	Updates public dataflow API to shared node types and switches closure to fastTC (+ identity).
csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowDispatch.qll	Refactors dataflow-call control-flow anchoring and multi-body callable handling to shared CFG types.
csharp/ql/lib/semmle/code/csharp/dataflow/internal/BaseSSA.qll	Updates BaseSSA to shared BasicBlock/Cfg types.
csharp/ql/lib/semmle/code/csharp/controlflow/internal/Splitting.qll	Removes legacy CFG splitting implementation (now handled by shared CFG).
csharp/ql/lib/semmle/code/csharp/controlflow/internal/NonReturning.qll	Simplifies non-returning call/callable modeling after CFG changes.
csharp/ql/lib/semmle/code/csharp/controlflow/Guards.qll	Updates guard modeling to shared CFG node/basic-block types and successor kinds.
csharp/ql/lib/semmle/code/csharp/controlflow/ControlFlowReachability.qll	Updates reachability config input types to shared CFG nodes/basic blocks.
csharp/ql/lib/semmle/code/csharp/controlflow/ControlFlowElement.qll	Reworks element↔node mapping to shared CFG injection model and introduces ControlFlowElementOrCallable.
csharp/ql/lib/semmle/code/csharp/controlflow/BasicBlocks.qll	Removes legacy BasicBlocks wrapper module (replaced by shared CFG basic blocks).
csharp/ql/lib/semmle/code/csharp/Callable.qll	Updates callable base class and entry/exit point types to shared CFG nodes.
csharp/ql/lib/semmle/code/csharp/Caching.qll	Removes legacy ControlFlowStage caching that depended on old splitting.
csharp/ql/lib/semmle/code/csharp/Assignable.qll	Updates assignable read/definition APIs to shared node/basic-block types.
csharp/ql/lib/printCfg.ql	Updates print-CFG contextual query to use shared ControlFlow::ViewCfgQuery inputs and new CFG scopes.
csharp/ql/consistency-queries/VariableCaptureConsistency.ql	Removes legacy basic-block uniqueness wrapper tied to old CFG scope mapping.
csharp/ql/consistency-queries/DataFlowConsistency.ql	Removes legacy CFG-scope exclusions and adjusts exclusions for accessor calls that are both read/write.
csharp/ql/consistency-queries/CfgConsistency.ql	Switches to shared ControlFlow::Consistency module.
csharp/ql/campaigns/Solorigate/src/ModifiedFnvFunctionDetection.ql	Updates loop-exit control-flow anchoring to shared node predicates.

Copilot's findings

• Files reviewed: 101/110 changed files
• Comments generated: 0