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Diffstat (limited to 'src/go/types/lookup.go')
-rw-r--r--src/go/types/lookup.go109
1 files changed, 49 insertions, 60 deletions
diff --git a/src/go/types/lookup.go b/src/go/types/lookup.go
index 9c7bfd4bb9..7cab336dbe 100644
--- a/src/go/types/lookup.go
+++ b/src/go/types/lookup.go
@@ -8,6 +8,11 @@ package types
import "go/token"
+// Internal use of LookupFieldOrMethod: If the obj result is a method
+// associated with a concrete (non-interface) type, the method's signature
+// may not be fully set up. Call Checker.objDecl(obj, nil) before accessing
+// the method's type.
+
// LookupFieldOrMethod looks up a field or method with given package and name
// in T and returns the corresponding *Var or *Func, an index sequence, and a
// bool indicating if there were any pointer indirections on the path to the
@@ -35,19 +40,6 @@ import "go/token"
// the method's formal receiver base type, nor was the receiver addressable.
//
func LookupFieldOrMethod(T Type, addressable bool, pkg *Package, name string) (obj Object, index []int, indirect bool) {
- return (*Checker)(nil).lookupFieldOrMethod(T, addressable, pkg, name)
-}
-
-// Internal use of Checker.lookupFieldOrMethod: If the obj result is a method
-// associated with a concrete (non-interface) type, the method's signature
-// may not be fully set up. Call Checker.objDecl(obj, nil) before accessing
-// the method's type.
-// TODO(gri) Now that we provide the *Checker, we can probably remove this
-// caveat by calling Checker.objDecl from lookupFieldOrMethod. Investigate.
-
-// lookupFieldOrMethod is like the external version but completes interfaces
-// as necessary.
-func (check *Checker) lookupFieldOrMethod(T Type, addressable bool, pkg *Package, name string) (obj Object, index []int, indirect bool) {
// Methods cannot be associated to a named pointer type
// (spec: "The type denoted by T is called the receiver base type;
// it must not be a pointer or interface type and it must be declared
@@ -56,8 +48,8 @@ func (check *Checker) lookupFieldOrMethod(T Type, addressable bool, pkg *Package
// pointer type but discard the result if it is a method since we would
// not have found it for T (see also issue 8590).
if t := asNamed(T); t != nil {
- if p, _ := t.underlying.(*Pointer); p != nil {
- obj, index, indirect = check.rawLookupFieldOrMethod(p, false, pkg, name)
+ if p, _ := t.Underlying().(*Pointer); p != nil {
+ obj, index, indirect = lookupFieldOrMethod(p, false, pkg, name)
if _, ok := obj.(*Func); ok {
return nil, nil, false
}
@@ -65,7 +57,7 @@ func (check *Checker) lookupFieldOrMethod(T Type, addressable bool, pkg *Package
}
}
- return check.rawLookupFieldOrMethod(T, addressable, pkg, name)
+ return lookupFieldOrMethod(T, addressable, pkg, name)
}
// TODO(gri) The named type consolidation and seen maps below must be
@@ -73,10 +65,9 @@ func (check *Checker) lookupFieldOrMethod(T Type, addressable bool, pkg *Package
// types always have only one representation (even when imported
// indirectly via different packages.)
-// rawLookupFieldOrMethod should only be called by lookupFieldOrMethod and missingMethod.
-func (check *Checker) rawLookupFieldOrMethod(T Type, addressable bool, pkg *Package, name string) (obj Object, index []int, indirect bool) {
+// lookupFieldOrMethod should only be called by LookupFieldOrMethod and missingMethod.
+func lookupFieldOrMethod(T Type, addressable bool, pkg *Package, name string) (obj Object, index []int, indirect bool) {
// WARNING: The code in this function is extremely subtle - do not modify casually!
- // This function and NewMethodSet should be kept in sync.
if name == "_" {
return // blank fields/methods are never found
@@ -84,10 +75,12 @@ func (check *Checker) rawLookupFieldOrMethod(T Type, addressable bool, pkg *Pack
typ, isPtr := deref(T)
- // *typ where typ is an interface has no methods.
- // Be cautious: typ may be nil (issue 39634, crash #3).
- if typ == nil || isPtr && IsInterface(typ) {
- return
+ // *typ where typ is an interface or type parameter has no methods.
+ switch under(typ).(type) {
+ case *Interface, *TypeParam:
+ if isPtr {
+ return
+ }
}
// Start with typ as single entry at shallowest depth.
@@ -107,7 +100,7 @@ func (check *Checker) rawLookupFieldOrMethod(T Type, addressable bool, pkg *Pack
var next []embeddedType // embedded types found at current depth
// look for (pkg, name) in all types at current depth
- var tpar *_TypeParam // set if obj receiver is a type parameter
+ var tpar *TypeParam // set if obj receiver is a type parameter
for _, e := range current {
typ := e.typ
@@ -128,6 +121,7 @@ func (check *Checker) rawLookupFieldOrMethod(T Type, addressable bool, pkg *Pack
seen[named] = true
// look for a matching attached method
+ named.load()
if i, m := lookupMethod(named.methods, pkg, name); m != nil {
// potential match
// caution: method may not have a proper signature yet
@@ -185,9 +179,7 @@ func (check *Checker) rawLookupFieldOrMethod(T Type, addressable bool, pkg *Pack
case *Interface:
// look for a matching method
- // TODO(gri) t.allMethods is sorted - use binary search
- check.completeInterface(token.NoPos, t)
- if i, m := lookupMethod(t.allMethods, pkg, name); m != nil {
+ if i, m := t.typeSet().LookupMethod(pkg, name); m != nil {
assert(m.typ != nil)
index = concat(e.index, i)
if obj != nil || e.multiples {
@@ -197,10 +189,8 @@ func (check *Checker) rawLookupFieldOrMethod(T Type, addressable bool, pkg *Pack
indirect = e.indirect
}
- case *_TypeParam:
- // only consider explicit methods in the type parameter bound, not
- // methods that may be common to all types in the type list.
- if i, m := lookupMethod(t.Bound().allMethods, pkg, name); m != nil {
+ case *TypeParam:
+ if i, m := t.iface().typeSet().LookupMethod(pkg, name); m != nil {
assert(m.typ != nil)
index = concat(e.index, i)
if obj != nil || e.multiples {
@@ -229,7 +219,7 @@ func (check *Checker) rawLookupFieldOrMethod(T Type, addressable bool, pkg *Pack
return
}
- current = check.consolidateMultiples(next)
+ current = consolidateMultiples(next)
}
return nil, nil, false // not found
@@ -246,7 +236,7 @@ type embeddedType struct {
// consolidateMultiples collects multiple list entries with the same type
// into a single entry marked as containing multiples. The result is the
// consolidated list.
-func (check *Checker) consolidateMultiples(list []embeddedType) []embeddedType {
+func consolidateMultiples(list []embeddedType) []embeddedType {
if len(list) <= 1 {
return list // at most one entry - nothing to do
}
@@ -254,7 +244,7 @@ func (check *Checker) consolidateMultiples(list []embeddedType) []embeddedType {
n := 0 // number of entries w/ unique type
prev := make(map[Type]int) // index at which type was previously seen
for _, e := range list {
- if i, found := check.lookupType(prev, e.typ); found {
+ if i, found := lookupType(prev, e.typ); found {
list[i].multiples = true
// ignore this entry
} else {
@@ -266,14 +256,14 @@ func (check *Checker) consolidateMultiples(list []embeddedType) []embeddedType {
return list[:n]
}
-func (check *Checker) lookupType(m map[Type]int, typ Type) (int, bool) {
+func lookupType(m map[Type]int, typ Type) (int, bool) {
// fast path: maybe the types are equal
if i, found := m[typ]; found {
return i, true
}
for t, i := range m {
- if check.identical(t, typ) {
+ if Identical(t, typ) {
return i, true
}
}
@@ -306,40 +296,40 @@ func MissingMethod(V Type, T *Interface, static bool) (method *Func, wrongType b
// To improve error messages, also report the wrong signature
// when the method exists on *V instead of V.
func (check *Checker) missingMethod(V Type, T *Interface, static bool) (method, wrongType *Func) {
- check.completeInterface(token.NoPos, T)
-
// fast path for common case
if T.Empty() {
return
}
if ityp := asInterface(V); ityp != nil {
- check.completeInterface(token.NoPos, ityp)
- // TODO(gri) allMethods is sorted - can do this more efficiently
- for _, m := range T.allMethods {
- _, f := lookupMethod(ityp.allMethods, m.pkg, m.name)
+ // TODO(gri) the methods are sorted - could do this more efficiently
+ for _, m := range T.typeSet().methods {
+ _, f := ityp.typeSet().LookupMethod(m.pkg, m.name)
if f == nil {
- // if m is the magic method == we're ok (interfaces are comparable)
- if m.name == "==" || !static {
+ if !static {
continue
}
return m, f
}
+ // both methods must have the same number of type parameters
ftyp := f.typ.(*Signature)
mtyp := m.typ.(*Signature)
- if len(ftyp.tparams) != len(mtyp.tparams) {
+ if ftyp.TParams().Len() != mtyp.TParams().Len() {
return m, f
}
+ if ftyp.TParams().Len() > 0 {
+ panic("internal error: method with type parameters")
+ }
// If the methods have type parameters we don't care whether they
// are the same or not, as long as they match up. Use unification
// to see if they can be made to match.
// TODO(gri) is this always correct? what about type bounds?
// (Alternative is to rename/subst type parameters and compare.)
- u := newUnifier(check, true)
- u.x.init(ftyp.tparams)
+ u := newUnifier(true)
+ u.x.init(ftyp.TParams().list())
if !u.unify(ftyp, mtyp) {
return m, f
}
@@ -351,14 +341,14 @@ func (check *Checker) missingMethod(V Type, T *Interface, static bool) (method,
// A concrete type implements T if it implements all methods of T.
Vd, _ := deref(V)
Vn := asNamed(Vd)
- for _, m := range T.allMethods {
+ for _, m := range T.typeSet().methods {
// TODO(gri) should this be calling lookupFieldOrMethod instead (and why not)?
- obj, _, _ := check.rawLookupFieldOrMethod(V, false, m.pkg, m.name)
+ obj, _, _ := lookupFieldOrMethod(V, false, m.pkg, m.name)
// Check if *V implements this method of T.
if obj == nil {
ptr := NewPointer(V)
- obj, _, _ = check.rawLookupFieldOrMethod(ptr, false, m.pkg, m.name)
+ obj, _, _ = lookupFieldOrMethod(ptr, false, m.pkg, m.name)
if obj != nil {
return m, obj.(*Func)
}
@@ -367,10 +357,6 @@ func (check *Checker) missingMethod(V Type, T *Interface, static bool) (method,
// we must have a method (not a field of matching function type)
f, _ := obj.(*Func)
if f == nil {
- // if m is the magic method == and V is comparable, we're ok
- if m.name == "==" && Comparable(V) {
- continue
- }
return m, nil
}
@@ -382,9 +368,12 @@ func (check *Checker) missingMethod(V Type, T *Interface, static bool) (method,
// both methods must have the same number of type parameters
ftyp := f.typ.(*Signature)
mtyp := m.typ.(*Signature)
- if len(ftyp.tparams) != len(mtyp.tparams) {
+ if ftyp.TParams().Len() != mtyp.TParams().Len() {
return m, f
}
+ if ftyp.TParams().Len() > 0 {
+ panic("internal error: method with type parameters")
+ }
// If V is a (instantiated) generic type, its methods are still
// parameterized using the original (declaration) receiver type
@@ -393,17 +382,17 @@ func (check *Checker) missingMethod(V Type, T *Interface, static bool) (method,
// In order to compare the signatures, substitute the receiver
// type parameters of ftyp with V's instantiation type arguments.
// This lazily instantiates the signature of method f.
- if Vn != nil && len(Vn.tparams) > 0 {
+ if Vn != nil && Vn.TParams().Len() > 0 {
// Be careful: The number of type arguments may not match
// the number of receiver parameters. If so, an error was
// reported earlier but the length discrepancy is still
// here. Exit early in this case to prevent an assertion
// failure in makeSubstMap.
// TODO(gri) Can we avoid this check by fixing the lengths?
- if len(ftyp.rparams) != len(Vn.targs) {
+ if len(ftyp.RParams().list()) != len(Vn.targs) {
return
}
- ftyp = check.subst(token.NoPos, ftyp, makeSubstMap(ftyp.rparams, Vn.targs)).(*Signature)
+ ftyp = check.subst(token.NoPos, ftyp, makeSubstMap(ftyp.RParams().list(), Vn.targs)).(*Signature)
}
// If the methods have type parameters we don't care whether they
@@ -411,8 +400,8 @@ func (check *Checker) missingMethod(V Type, T *Interface, static bool) (method,
// to see if they can be made to match.
// TODO(gri) is this always correct? what about type bounds?
// (Alternative is to rename/subst type parameters and compare.)
- u := newUnifier(check, true)
- u.x.init(ftyp.tparams)
+ u := newUnifier(true)
+ u.x.init(ftyp.RParams().list())
if !u.unify(ftyp, mtyp) {
return m, f
}
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