The project listed 201 explicit <Compile Include> and 119 <None Include> items
with EnableDefaultItems=false. Many test-case sources had been marked <None>
only because the C# compiler available when they were written could not build
them; the current Roslyn compiles them fine. The hand-maintained lists had also
drifted: five committed fixtures (Operators.cs, Issue3751.cs, three ILPretty
.cs) were on disk with passing tests but in no item list.
Switch to the SDK default **/*.cs glob and exclude only the sources that still
cannot be compiled into the test assembly, determined empirically by building
with everything included and removing what failed:
- IL-pretty inputs that are not valid standalone C# and *.Expected.cs golden
outputs that reuse type names (compile errors / duplicate definitions).
- MetadataAttributes.cs, which applies assembly/module attributes that break
NUnit test discovery (zero tests found) when compiled into the assembly.
The excluded sources stay <None> for IDE visibility; the harness compiles them
from disk at test time regardless. This compiles 23 more fixtures than before
while keeping every previously-compiled file. Default None globbing stays off so
the non-C# inputs (.il/.vb/.fs) remain the authoritative list.
Operators.cs, now part of the build, is normalized to the repo's tab indentation
by the format hook (a CS110 block used spaces). Verified: the full suite still
reports 2257 passed, 0 failed, 35 skipped.
Assisted-by: Claude:claude-opus-4-8:Claude Code
A stackalloc whose result is a pointer is only valid C# as the initializer of a
pointer-typed local. The inliner moved a single-use pointer stackalloc into its
use, producing e.g. 'K.V(stackalloc int[3] { 1, 2, v })' or '*stackalloc ...';
in an expression position the stackalloc is typed as Span<T>, which does not
convert to a pointer, so the output did not compile. Keep such a stackalloc as a
separate local. Moving it into a local store (its declaration) and into the
Span<T>/ReadOnlySpan<T> constructor stay allowed, since those are the positions
where the pointer or span form is exactly what is wanted.
Found while exploring stackalloc-initializer coverage.
Assisted-by: Claude:claude-opus-4-8:Claude Code
HandleSequentialLocAllocInitializer formed a stackalloc initializer whenever the
explicit stores were contiguous from offset 0, even if they did not cover the
whole buffer. A 'stackalloc byte[16]' reinterpreted as int and written through
three of its four elements decompiled to 'stackalloc int[4] { 1, v, 3 }', whose
initializer has fewer elements than the declared length and does not compile.
Require every element to be written (from the constant data blob or an explicit
store) before forming the initializer; otherwise the buffer stays a plain
stackalloc with individual stores.
Found while exploring stackalloc-initializer coverage.
Assisted-by: Claude:claude-opus-4-8:Claude Code
A constant-size stackalloc initializer stores its constant elements through a
data blob (cpblk from a <PrivateImplementationDetails> field). ReadElement
decoded every element by width, so a 4-byte float was read as Int32 and an
8-byte double as Int64. The resulting constant carried the raw bit pattern
(1f decoded as 1.0653532E+09f) and its stack type no longer matched the store,
tripping StObj.CheckInvariant. Dispatch on the element's type code so Single and
Double are read as floating-point, matching the heap-array decoder.
Found while exploring stackalloc-initializer coverage around the element-type
hint fix; floating-point element types had no test case.
Assisted-by: Claude:claude-opus-4-8:Claude Code
A constant-size stackalloc initializer whose buffer is only passed to a static
call (never dereferenced as a typed pointer) threw "given Block is invalid!".
TranslateStackAllocInitializer recovers the element type from the surrounding
type hint, but that hint is unreliable for this shape: the constant allocation
size is folded to a byte count, so it can no longer be read off a
'count * sizeof(T)' expression, and the buffer is kept on the stack as a native
int instead of a T* local, leaving the hint a non-pointer. The guard only
repaired an incompatible pointer hint, so a non-pointer hint fell through to a
'byte' element type that is incompatible with the actual stores, and the
per-element check threw. Derive the element type from the type being stored
whenever the hint is not already a compatible pointer.
The regression is driven by the code shape, not the compiler version: in
optimized builds the buffer is kept on the stack as a native int whenever it is
passed to a static call without being dereferenced. This reproduces across
Roslyn versions, including the pinned test compiler, so the added fixture is red
without this fix in the optimized configurations.
Assisted-by: Claude:claude-opus-4-8:Claude Code
The generated GetChildNodes materialized a List<AstNode> (plus a boxed
List.Enumerator at every foreach) for each node, so AstNode.Children and
the visitor's per-node child walk allocated three objects per traversal.
Decompiling System.Private.CoreLib that came to ~1.7 GB of extra garbage,
roughly +7% over the linked-list model the slot tree replaced. A yield
iterator removes the List but trades it for an equally costly per-node
state machine, so it is not enough on its own.
Enumerate children through a by-value struct enumerator over the existing
FirstChild/NextSibling primitives, capturing each child's successor before
it is yielded so a transform may still remove or replace the current child
mid-traversal. AstNodeCollection<T> gets the same struct treatment for a
direct foreach. Child enumeration now allocates nothing, bringing total
allocations back to the linked-list baseline at byte-identical output
(full Pretty suite green with CheckInvariant active).
Assisted-by: Claude:claude-opus-4-8:Claude Code
Two crash paths surfaced by the null-object -> nullable-reference migration of the
C# AST. A void 'return;' forced into lambda syntax NRE'd on
ReturnStatement.Expression.Detach() now that Expression is nullable; the body now
falls through to the block form, matching the existing guards in CallBuilder and
InferReturnType. Separately, the location-setting token decorator routed a parentless
print-only node (e.g. the detached name-token clone of a renamed constructor) into the
child setter as SlotKind.None, which throws since the Role hierarchy was removed; such
nodes have no slot and are now skipped. A regression test covers the decorator path.
Assisted-by: Claude:claude-opus-4-8:Claude Code
The pattern matcher walked collections through INode.Role/FirstChild/
NextSibling, skipping siblings of a different role. Now that each
AstNodeCollection<T> is already the per-role child list, the engine matches two
collections by list index, and INode sheds Role/FirstChild/NextSibling
entirely. A collection exposes its IReadOnlyList<INode> view through a cached
adapter rather than implementing the interface directly, so a typed collection
does not become ambiguous for LINQ. Characterization tests pin the matcher's
behavior first.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Source locations were virtual, computed by recursing to the first and last
child, whose leftmost and rightmost leaves are token nodes; sequence-point
coordinates likewise came from reconstructed token nodes. Store locations as
fields assigned while printing, and derive sequence-point coordinates from the
surrounding real nodes plus the decompiler's fixed formatting, so neither
depends on token children. The using/foreach await modifier becomes a plain
bool field. Characterization gates lock the emitted locations and PDB
coordinates, which are unchanged.
Assisted-by: Claude:claude-opus-4-8:Claude Code
The InsertMissingTokensDecorator path (TokenWriter.CreateWriterThatSetsLocationsInAST)
reconstructs token nodes and assigns source locations onto the AST, feeding PDB
sequence points and GUI navigation. The Pretty suite never drives it, so it had no
coverage at all. Before reworking the token model, lock its observable consequences:
the located path emits the same text as the plain path, real nodes receive ordered
locations, location-based navigation resolves into the method body, and sequence
points are produced for a method body.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Introduce a Roslyn source generator that emits the visitor boilerplate for
the C# AST from [DecompilerAstNode]-tagged node declarations: the
IAstVisitor interface, the AcceptVisitor overloads, the pattern-placeholder
nodes, and the initial DoMatch support. AccessorKind lets an accessor's
keyword be chosen independently of its role, an early step toward shedding
the NRefactory role model.
The "IL with C#" view decompiles each method body as a bare handle, so a
static constructor is decompiled without its type's field declarations in
the syntax tree. MoveFieldInitializersToDeclarations then could not find a
declaration to move the static-field-initializer statement onto, asserted
(kind was Static, not Primary) and dropped the statement -- crashing Debug
builds and silently losing the assignment in Release.
Dropping the statement is only correct for the primary-constructor case,
where the assignment's backing member is synthesized and has no separate
declaration. For static/instance initializers a missing declaration just
means the member is not part of this partial syntax tree, so the
assignment must remain in the constructor body.
Assisted-by: Claude:claude-opus-4-8:Claude Code
CopyFSharpCoreDll built the ILSpy-tests path with hardcoded Windows backslashes
("..\\..\\..\\ILSpy-tests\\FSharp\\FSharp.Core.dll"). On non-Windows, '\' is a
normal filename character, so the whole string became a single bogus path,
File.Exists always returned false, and the FSharp ILPretty tests were silently
Assert.Ignore'd even when ILSpy-tests was checked out. Build the path from
Path.Combine segments instead so it resolves on every platform (same target:
three levels up from the ILPretty test-case directory).
Assisted-by: Claude:claude-opus-4-8:Claude Code
On FIPS-mode systems the platform crypto provider refuses to create
SHA-1 instances (OpenSSL: error:03000098 invalid digest), so merely
displaying a strong-named assembly's identity failed. The public-key
token is a non-secret identity hash whose algorithm is fixed by
ECMA-335, so the two token sites now use dotnet/runtime's managed
Sha1ForNonSecretPurposes, vendored with its license header intact and
shielded from the repo formatter via generated_code in .editorconfig
so future upstream syncs diff cleanly. IncrementalHash was considered
and rejected: like SHA1.Create(), it resolves the digest through the
host crypto policy, and Roslyn's equivalent token code also relies on
the platform SHA-1, so it offers no precedent for FIPS safety.
Assisted-by: Claude:claude-fable-5:Claude Code
Windows maps CON, PRN, AUX, NUL, COM1-9 and LPT1-9 to devices -- on many
builds even with an extension appended, so a type named Con made both
whole-project export and the save dialog fail with IOException '\\.\Con'.
CleanUpName only checked for reserved names after re-appending the file
extension, where they never match, and the save-dialog default-name
helpers did not check them at all. The escape appends the underscore to
the base name (con_.txt, not con.txt_) because device-name parsing
ignores everything after the first dot, and is applied per path segment
so reserved directory names produced by namespaces are covered too. The
ILSpy.Tests.Windows fixture verifies on a real Windows filesystem that
the escaped names are creatable.
Assisted-by: Claude:claude-fable-5:Claude Code
Compilation uses the .NET builds of the Roslyn toolsets (tasks/netcore*,
bincore csc.dll/vbc.dll launched through the dotnet host). ilasm/ildasm
options use the '-' prefix, which all platforms accept. The dotnet-hosted
compilers have no implicit references or SDK path: net40 compiles pass
mscorlib explicitly, and vbc gets -sdkpath, _MYTYPE=Empty and
-vbruntime:Microsoft.VisualBasic.Core.dll (the facade in the ref packs is
not followed for runtime helpers). The TestRunner gets a self-contained
build for the host platform.
Configurations depending on Windows-only tools or runtimes (legacy
csc/vbc, Roslyn 1.x/2.x, mcs, Force32Bit, executing net40 binaries) are
filtered from the matrix off-Windows via Tester.SupportedOnCurrentPlatform
or gated with [Platform("Win")]. PdbGen comparisons normalize document
name separators, and Correctness/Async uses Console.IsInputRedirected
instead of the Windows-only Console.CapsLock.
Assisted-by: Claude:claude-fable-5:Claude Code
Captures the compiler-matrix model, the test kinds and their pipelines,
how to add tests per kind, the #if/preprocessor-symbol comparison rules,
and the probe-a-construct-across-all-compilers workflow, so this no
longer has to be reverse-engineered from the runners.
Assisted-by: Claude:claude-fable-5:Claude Code
The decompiled view only offered navigation on member names; finding
what an override actually overrides required opening the analyzer.
Attaching a reference to the modifier token gives the same
go-to-definition affordance Visual Studio has on 'override'. The
reference resolves via InheritanceHelper.GetBaseMember, so it targets
the nearest overridden member and degrades to plain text when the base
member cannot be resolved.
Assisted-by: Claude:claude-fable-5:Claude Code
When enabled, switch sections are ordered by their case label value
instead of by the underlying branch's IL offset. Default is false to
keep existing output unchanged. Useful when diffing decompiler output
across rebuilds of obfuscated assemblies, where IL block layout is
unstable but the case-to-value mapping is not.
Includes an ILPretty test that exercises a hand-written switch whose
table targets are placed at non-monotonic IL offsets (simulating
obfuscator block shuffling) and verifies the cases come out in
label-value order with the setting enabled. Also adds the
Resources.resx / Resources.Designer.cs entry so the WPF settings UI
shows a proper label instead of the raw key.
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
* Fix anonymous-type lambda early-return emitting unresolvable cast
When a lambda's inferred return type contains an anonymous type and one
branch returns null, the decompiler emitted an explicit cast such as
`return (IEnumerable<<>f__AnonymousType0<int>>)null;`, which is invalid C#.
Skip the cast in IsPossibleLossOfTypeInformation for null literals whenever
the expected type contains an anonymous type:
null is implicitly convertible to any reference type, so no cast is needed,
and the anonymous type has no nameable form to cast to anyway.
Fixes#3751
The Microsoft.DiaSymReader / .PortablePdb packages pull NETStandard.Library
1.6.1, which drags in 4.3.0 builds of System.Net.Http, System.Private.Uri
and System.Text.RegularExpressions, all carrying known advisories (NU1902/
NU1903). They are framework-provided at runtime on net10.0; pin the patched
4.3.4 / 4.3.2 / 4.3.1 via central transitive pinning so NuGet audit passes.
Enabling transitive pinning also aligns a handful of other transitive
packages to their declared central versions.
Assisted-by: Claude:claude-opus-4-8:Claude Code
The Pdb2Xml command (ILSpy) and the PDB round-trip tests (Decompiler.Tests)
reference Microsoft.DiaSymReader*, previously gated on the build host being
Windows. That made dotnet restore resolve a different graph on Windows than
on Linux -- the packages (and their transitive tail: DiaSymReader.PortablePdb,
the legacy NETCore.Platforms/Win32 packages) appear only on Windows, and
DiaSymReader.Native flips between Direct and CentralTransitive. So a checkout
could not be developed across OSes without the committed packages.lock.json
churning on every Windows restore.
Drop the OS gate (keep Debug-only) so the restored graph, and the committed
lock, are identical on every OS. The consuming code is still gated by DEBUG
and WINDOWS, so on non-Windows the packages are restored but never compiled
in; the native asset only resolves for win-* RIDs.
The "Verify package contents" step (which checks the committed *.filelist
snapshots still match the built VSIX/MSI contents) had been excluding
packages.lock.json from its git diff to tolerate that per-OS churn. With the
locks now identical across OSes the carve-out is unnecessary, so it goes back
to a plain git diff --exit-code.
Assisted-by: Claude:claude-opus-4-8:Claude Code
ICSharpCode.Decompiler.Tests builds for the host RID (so the native
Microsoft.DiaSymReader.Native assets the Windows PDB tests need are copied),
which made its packages.lock.json host-specific (linux-x64 vs win-x64) and
drift between Linux and Windows restores. Add an explicit <RuntimeIdentifiers>
list next to the single <RuntimeIdentifier>: the lock then records every RID
host-independently while the build still targets the host RID. Apply the same
list to the TestRunner it pulls in.
TestRunner's lock is now fully portable. The test project's lock still carries
the OS-conditional DiaSymReader.Native difference in its base graph, which the
*.filelist-scoped "Verify package contents" step already tolerates.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Replace the Windows-only .bat helpers (clean / debugbuild / releasebuild /
restore / updatedeps and BuildTools/format) with cross-platform pwsh
scripts at the repo root: restore.ps1, build.ps1 (-Configuration), clean.ps1,
updatedeps.ps1 and BuildTools/format.ps1, alongside the existing publish.ps1.
Enable a packages.lock.json for every project by hoisting
RestorePackagesWithLockFile into the root Directory.Build.props (the four
core libraries set it individually before) and commit the generated locks,
so restores are repeatable and CI can cache packages off them.
Cache the NuGet packages folder in the three setup-dotnet workflows
(build-ilspy, build-frontends, codeql-analysis), keyed on the lock files
per the setup-dotnet caching guidance.
Scope the Debug "Verify package contents" check to the *.filelist outputs
it actually generates. A project's packages.lock.json is keyed only by
(framework, RID), with no host-OS axis, so a lock produced on Linux
legitimately differs from one produced on Windows whenever an OS-conditional
PackageReference applies (Debug+Windows pulls Microsoft.DiaSymReader*). The
Windows restore then rewrites those locks; that churn must not fail a step
whose job is to police the VSIX/MSI file lists.
Also drop the dead ILSpy.BamlDecompiler publish line from
publishlocaldev.ps1, mirroring the earlier publish.ps1 fix.
Assisted-by: Claude:claude-opus-4-8:Claude Code
The portable-PDB writer carried its knobs (no-logo, pdb id, progress,
progress title) as a growing list of optional WritePdb parameters.
Turn the type into a configured instance whose options are properties,
and add EmbedSourceFiles (default true): when a PDB is generated next
to a project export whose .cs are already on disk, embedding the source
again is redundant, so the caller can turn it off. The per-document
checksum/hash is computed either way, so documents still resolve.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Decompiler.Tests targeted net11.0-windows only because
Microsoft.DiaSymReader.Native is Win-only and Tester.cs hardcoded ilasm.exe
/ ildasm.exe filenames. Both are narrow problems: gate the Native package
to Windows, replace the ".exe" suffix with an OS-aware helper, and drop
the -windows TFM. The Microsoft.NETCore.IL{,D}Asm metapackages' RID graph
already ships ilasm/ildasm for linux + osx via per-RID runtime sub-packages
when RuntimeIdentifier resolves dynamically, so the tool just lands in the
test output dir with the right suffix on every host.
Windows-only test fixtures (RoundtripAssembly + the RunWithTestRunner,
SignAssembly, FindMSBuild call sites) gate via Assert.Ignore +
[Platform("Win")] so they skip on non-Windows instead of failing. CA1416
joins NoWarn -- the analyzer can't see the runtime guards, and the test
inputs (Console.CapsLock, Registry access) are decompilation targets, not
infrastructure.
BuildTools/pre-commit learns to find dotnet-format on non-Windows (XDG
basedir + no .exe suffix) so the hook can run wherever the build now does.
Assisted-by: Claude:claude-opus-4-7:Claude Code
The multi-handler matcher only recognized a switch-instruction dispatch — but
when a try-catch has just two handlers (or a handful with non-consecutive K
values), Roslyn emits an if-chain instead:
if (num == K_1) br case_K_1; br nextBlock
; nextBlock { if (num == K_2) br case_K_2; <leave outer | br end> }
Add a parallel matcher that walks the if-chain and collects (K, case-block)
pairs the same way MatchSwitchDispatch does, plus the terminating leave/branch
as the default exit. Call it as a fallback when the switch matcher rejects.
Also clone the default-exit before re-adding it to the continuation block —
in the if-chain shape it's a child of a *different* block (a later step in
the chain), not the now-cleared switch instruction, so the in-place re-add
relied on the switch's release cascade and didn't generalize.
Closes Cluster 2 from #3745.
The flag-based early-return rewriter was tied to one specific lowered shape:
the try body's flag-setter had to be exactly `stloc flag(K); leave try`, the
post-try check had to be a `br checkBlock` (not an inline `IfInstruction`), and
the early path had to be a direct Leave or a forward to a one-instruction
leave-block whose target was the function body. None of those hold for
`try { try { return X; } finally { await ... } } finally { await ... }`:
- The inner flag-setter has a leading capture-forwarding store
(`stloc capture(X); stloc innerFlag(K); leave inner-try`).
- The inner check-block's early path branches to a multi-instruction helper
that sets the *outer* flag and leaves the outer try, instead of being a
direct return.
- SplitVariables hands out a separate ILVariable for the pre-init flag store
when the in-handler store is in a disjoint dataflow region.
Rebuild the matcher around the idea of a "template" — the chain of stores
the early path performs before its terminating Leave. Each flag-setter then
becomes its own prefix stores + a clone of the template, which collapses the
inner-then-outer flag chain in two passes (inner first, outer second, because
descendant order visits the inner TryFinally first). Also extend the
flag-setter scan to walk the whole try-block's descendants — after the inner
rewrite, the inner's spliced flag-setter lives inside the inner-try container
but still leaves outwards to the outer try, so it's an outer flag-setter from
the outer's perspective.
Add a `RUNTIMEASYNC` preprocessor symbol (defined when `EnableRuntimeAsync`
is set) and gate the new return-from-try-finally fixtures on it — the
state-machine async pipeline doesn't recover this shape, so it would expand
the same source into the `int result; try { ...; result = X; } finally { ... }
return result;` verbose form and the Async (state-machine) pretty test would
regress.
Closes Cluster 1 (1.1, 1.3) from #3745. Cluster 1.2 (void `return;` at the
end of a try-finally body) and 1.4 (break/continue across a try-finally) are
left for a follow-up: both round-trip semantically equivalently but the AST
emitter drops a trailing void `return;` and the break/continue lowering uses
a switch dispatch that the current single-K matcher can't recognize.
`try { throw new ...(); } finally { await ... }` lowers to a try whose only
exit is the throw (handled by the synthetic catch). The existing matcher
required at least one outward Branch to the continuation, which is too strict
— a throw-only try body produces zero outward branches but is still a valid
lowered shape. Two follow-on fixes were also needed:
- The pre-init's ILVariable diverges from the in-handler store after
SplitVariables when the try body has no path that reaches the dispatch's
load without going through the catch; match the flag init by slot/kind/type
instead of identity (same workaround the multi-handler matcher uses).
- With a throw-only try body the new TryFinally has unreachable endpoint,
so appending the no-exception successor after it would put a non-final
unreachable-endpoint instruction in the parent block. Skip the append in
that case — the parent block's endpoint is already correctly unreachable.
Closes Cluster 4 from #3745.
The single-handler try-catch matcher was tied to the top-level shape: it
required the try-catch be the last instruction in its parent block, that the
post-catch "no exception" path be a direct Leave that exits the function, and
that the flag-init's ILVariable be identical to the in-handler flag store.
None of those hold for an inner try-catch sitting inside an outer try-finally
where both await — the inner is followed by a `br continuation`, the no-exception
path leaves the outer try-block (not the function), and SplitVariables hands
out a separate ILVariable for the pre-init store.
Drop the "must be last instruction" gate, accept Leave-to-any-ancestor and
cross-container Branch as the no-exception exit (extracted into a new
`IsContainerExit` helper), and match the flag-init by slot/kind/type the same
way the multi-handler matcher already does.
Closes Cluster 3 from #3745.
Two methods exercise `Task<int>.ConfigureAwait(bool)`: a single false-flag form
and a mixed false/true form that combines two awaits in a return expression.
Both cases run through the regular state-machine and runtime-async pipelines
(RuntimeAsync reuses Async.cs as its source).
Gated by `#if ROSLYN2` because Roslyn 2+ preserves named-argument metadata at
the call site, so the decompiler renders `continueOnCapturedContext: false`
when the binary was compiled by Roslyn 2+ and positional `false` for default
csc / Roslyn 1.3.2.
Also adds NoInliningTaskMethod — an async method carrying
[MethodImpl(MethodImplOptions.NoInlining)] — so the runtime-async path
exercises the impl-attribute masking added in the scaffolding commit:
MetadataMethod strips the synthesized MethodImplOptions.Async (0x2000) bit
from the decompiled output, and unrelated impl bits like NoInlining (0x0008)
must still render in the surfaced [MethodImpl(...)] attribute.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Detect MethodImplOptions.Async (0x2000) in ILReader and unpack Task/Task<T>
return types so the IL Leave value and function.AsyncReturnType match the
source signature. Add CSharp15_0 (Preview also bumped to 1500) and a
RuntimeAsync setting (default on, gated to >=CSharp15_0), expose it in the
Languages dropdown, mask the synthetic MethodImplAsync bit out of the
decompiled [MethodImpl], and add a .runtimeasync test suffix.
* .NET 11 RC2 minimal changes
* Heuristic for transport feed Roslyn selection
* Microsoft.CodeAnalysis.NetAnalyzers from main NuGet feed
* Use the VS2026 image
* Switch all test projects to net11
* Extract constants
* Include vsix with plain nuget.config files
Siegfried Pammer
DoctorKrolic
danbopes
Jakob Hellermann
Christoph Wille