if n.state() >= resolved { // avoid locking below
		return n
	}

	// TODO(rfindley): if n.check is non-nil we can avoid locking here, since
	// type-checking is not concurrent. Evaluate if this is worth doing.
	n.mu.Lock()
	defer n.mu.Unlock()

	if n.state() >= resolved {
		return n
	}

	if n.inst != nil {
		assert(n.underlying == nil) // n is an unresolved instance

}

const maxStackSize = 1 << 30

// Compile builds an SSA backend function,
// uses it to generate a plist,
// and flushes that plist to machine code.
// worker indicates which of the backend workers is doing the processing.
func Compile(fn *ir.Func, worker int, profile *pgoir.Profile) {
	f := buildssa(fn, worker, inline.IsPgoHotFunc(fn, profile) || inline.HasPgoHotInline(fn))
	// Note: check arg size to fix issue 25507.

handling, at some cost in run time, is available by setting
GOEXPERIMENT=cgocheck2 at build time.

It is possible to defeat this enforcement by using the unsafe package,
and of course there is nothing stopping the C code from doing anything
it likes. However, programs that break these rules are likely to fail
in unexpected and unpredictable ways.

The runtime/cgo.Handle type can be used to safely pass Go values

var passes = [...]pass{
	{name: "number lines", fn: numberLines, required: true},
	{name: "early phielim and copyelim", fn: copyelim},
	{name: "early deadcode", fn: deadcode}, // remove generated dead code to avoid doing pointless work during opt
	{name: "short circuit", fn: shortcircuit},
	{name: "decompose user", fn: decomposeUser, required: true},
	{name: "pre-opt deadcode", fn: deadcode},

	if name == "_" {
		return // blank fields/methods are never found
	}

	// Importantly, we must not call under before the call to deref below (nor
	// does deref call under), as doing so could incorrectly result in finding
	// methods of the pointer base type when T is a (*Named) pointer type.
	typ, isPtr := deref(T)

	// *typ where typ is an interface (incl. a type parameter) has no methods.

	}
	return fmt.Sprintf("file[%d]", fileNo)
}

func (check *Checker) importPackage(pos syntax.Pos, path, dir string) *Package {
	// If we already have a package for the given (path, dir)
	// pair, use it instead of doing a full import.
	// Checker.impMap only caches packages that are marked Complete
	// or fake (dummy packages for failed imports). Incomplete but
	// non-fake packages do require an import to complete them.

	//            _cgo0 := p
	//            _cgoCheckPointer(_cgo0, nil)
	//            C.f(_cgo0)
	//    }()
	// Using a function literal like this lets us evaluate the
	// function arguments only once while doing pointer checks.
	// This is particularly useful when passing additional arguments
	// to _cgoCheckPointer, as done in checkIndex and checkAddr.
	//
	// When the function argument is a conversion to unsafe.Pointer,

			break
		}
		if advance {
			slow = slow.Args[0]
		}
		advance = !advance
	}

	// The answer is w.  Update all the copies we saw
	// to point directly to w.  Doing this update makes
	// sure that we don't end up doing O(n^2) work
	// for a chain of n copies.
	for v != w {
		x := v.Args[0]
		v.SetArg(0, w)
		v = x
	}
	return w
}

// copyelimValue ensures that no args of v are copies.

				fatal("%v", err)
			}
			if err = f.Close(); err != nil {
				fatal("error closing memory profile: %v", err)
			}
		})
	} else {
		// Not doing memory profiling; disable it entirely.
		runtime.MemProfileRate = 0
	}

	// Mode-dependent setup.
	op.Setup()

	// ... off and running now.
	dbgtrace(1, "starting perform")

	// there are params but no returns for ABI0->ABIInternal wrappers,
	// provided that all params fit into registers (e.g. we don't have
	// to allocate any stack space). Doing this will require some
	// extra work in typecheck/walk/ssa, might want to add a new node
	// OTAILCALL or something to this effect.