ADR 0012: Features considered and rejected

Status: Accepted; extended by 0031, which adopts := (rejected here) as the declaration of locals

Feature	Why rejected	Instead
:= declarations	Second syntax for val, read as mutable by Go users	val/var; E0005 explains
Fallibility inferred from ? in the body	API changes with implementation, invisible in signatures	explicit throws
Implicit numeric widening (Float64 * Int)	Hides precision loss and overflow, one of Go’s real strengths	E0202 with a fix-it
parallel for ... limit N syntax	Library-expressible with fallible lambdas, and would freeze semantics in the language	a lyth/conc library
lowerCamel aliases for Go APIs	Heuristics, collisions, two spellings	verbatim Go names (ADR 0010)
Receiver lambdas / implicit DSL receivers (get(...) { json(x) })	Hidden name resolution, type-system complexity	explicit lambda parameter, it
Dynamic route params params.id	Needs framework knowledge in the compiler or dynamic typing	c.PathValue("id")
Exceptions with unwinding	Hidden control flow, Go incompatibility	throws/?/catch
Operator overloading, macros	Unpredictable generated code; compile-time code execution	functions
$name template shorthand	Two template syntaxes; ${name} suffices	${...}; E0006 catches $name
Triple-quoted strings	Overlaps with Go raw strings	backtick raw strings
Function overloading	Go has none; mangled names hurt interop	distinct names