name string
}
+// An action describes a (delayed) action.
+type action struct {
+ f func() // action to be executed
+ desc *actionDesc // action description; may be nil, requires debug to be set
+}
+
+// If debug is set, describef sets a printf-formatted description for action a.
+// Otherwise, it is a no-op.
+func (a *action) describef(pos poser, format string, args ...interface{}) {
+ if debug {
+ a.desc = &actionDesc{pos, format, args}
+ }
+}
+
+// An actionDesc provides information on an action.
+// For debugging only.
+type actionDesc struct {
+ pos poser
+ format string
+ args []interface{}
+}
+
// A Checker maintains the state of the type checker.
// It must be created with NewChecker.
type Checker struct {
firstErr error // first error encountered
methods map[*TypeName][]*Func // maps package scope type names to associated non-blank (non-interface) methods
untyped map[syntax.Expr]exprInfo // map of expressions without final type
- delayed []func() // stack of delayed action segments; segments are processed in FIFO order
+ delayed []action // stack of delayed action segments; segments are processed in FIFO order
objPath []Object // path of object dependencies during type inference (for cycle reporting)
// context within which the current object is type-checked
// either at the end of the current statement, or in case of a local constant
// or variable declaration, before the constant or variable is in scope
// (so that f still sees the scope before any new declarations).
-func (check *Checker) later(f func()) {
- check.delayed = append(check.delayed, f)
+// later returns the pushed action so one can provide a description
+// via action.describef for debugging, if desired.
+func (check *Checker) later(f func()) *action {
+ i := len(check.delayed)
+ check.delayed = append(check.delayed, action{f: f})
+ return &check.delayed[i]
}
// push pushes obj onto the object path and returns its index in the path.
print := func(msg string) {
if check.conf.Trace {
+ fmt.Println()
fmt.Println(msg)
}
}
// add more actions (such as nested functions), so
// this is a sufficiently bounded process.
for i := top; i < len(check.delayed); i++ {
- check.delayed[i]() // may append to check.delayed
+ a := &check.delayed[i]
+ if check.conf.Trace && a.desc != nil {
+ fmt.Println()
+ check.trace(a.desc.pos.Pos(), "-- "+a.desc.format, a.desc.args...)
+ }
+ a.f() // may append to check.delayed
}
assert(top <= len(check.delayed)) // stack must not have shrunk
check.delayed = check.delayed[:top]
if res != nil {
// Calling under() here may lead to endless instantiations.
// Test case: type T[P any] T[P]
- // TODO(gri) investigate if that's a bug or to be expected.
under = safeUnderlying(res)
}
check.trace(pos, "=> %s (under = %s)", res, under)
}
}
tname := NewTypeName(pos, t.obj.pkg, t.obj.name, nil)
- named := check.newNamed(tname, t, nil, nil, nil) // methods and tparams are set when named is resolved
+ named := check.newNamed(tname, t, nil, nil, nil) // underlying, tparams, and methods are set when named is resolved
named.targs = NewTypeList(targs)
named.resolver = func(ctxt *Context, n *Named) (*TypeParamList, Type, []*Func) {
return expandNamed(ctxt, n, pos)