Shortening default(T) is the same problem as removing the redundant cast
around a lambda whose delegate type the context already fixes, so it uses
the same mechanism: ConvertTo makes the explicit type implicit when the
conversion is an identity conversion and the caller allows an implicit
one. The literal keeps the type it was shortened from, so any later
conversion to a different type - or any context that requires an explicit
type, such as an overload resolution recheck falling back to CastArguments
- can spell default(T) out again. That keeps the value intact where the
bare literal would change it, e.g. "object o = default(SomeStruct)", which
boxes a non-null struct while "default" would be null.
Because the shortened literal resolves to DefaultLiteralResolveResult,
CallBuilder's existing overload resolution recheck sees a real default
literal and rejects ambiguous calls on its own; no separate bookkeeping
about which arguments may stay untyped is needed. Only the contexts that
supply no target type at all restore the explicit form: an awaited
expression, and arguments of operator methods, which later become operator
or cast syntax rather than calls.
Assisted-by: Claude:claude-opus-5[1m]:Claude Code
HandleSimpleArrayInitializer multiplies the array dimensions to size the list
it collects elements into. The dimensions come from the input assembly and
need not multiply within int range, and ICSharpCode.Decompiler is built with
CheckForOverflowUnderflow, so an implausible pair of dimensions aborted
decompilation of the whole member. The product is only a capacity hint, so it
can saturate.
Found by fuzzing nuget.org; reproduces on obfuscated assemblies.
Assisted-by: Claude:claude-opus-5[1m]:Claude Code
Christoph Wille
Siegfried Pammer
Peter Crabtree
Daniel Grunwald