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path: root/src/go/types/expr.go
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Diffstat (limited to 'src/go/types/expr.go')
-rw-r--r--src/go/types/expr.go114
1 files changed, 76 insertions, 38 deletions
diff --git a/src/go/types/expr.go b/src/go/types/expr.go
index 58962e777b..c9a55aa871 100644
--- a/src/go/types/expr.go
+++ b/src/go/types/expr.go
@@ -144,6 +144,14 @@ var op2str2 = [...]string{
token.SHL: "shift",
}
+func underIs(typ Type, f func(Type) bool) bool {
+ u := under(typ)
+ if tpar, _ := u.(*TypeParam); tpar != nil {
+ return tpar.underIs(f)
+ }
+ return f(u)
+}
+
// The unary expression e may be nil. It's passed in for better error messages only.
func (check *Checker) unary(x *operand, e *ast.UnaryExpr) {
check.expr(x, e.X)
@@ -164,19 +172,29 @@ func (check *Checker) unary(x *operand, e *ast.UnaryExpr) {
return
case token.ARROW:
- typ := asChan(x.typ)
- if typ == nil {
- check.invalidOp(x, _InvalidReceive, "cannot receive from non-channel %s", x)
- x.mode = invalid
- return
- }
- if typ.dir == SendOnly {
- check.invalidOp(x, _InvalidReceive, "cannot receive from send-only channel %s", x)
+ var elem Type
+ if !underIs(x.typ, func(u Type) bool {
+ ch, _ := u.(*Chan)
+ if ch == nil {
+ check.invalidOp(x, _InvalidReceive, "cannot receive from non-channel %s", x)
+ return false
+ }
+ if ch.dir == SendOnly {
+ check.invalidOp(x, _InvalidReceive, "cannot receive from send-only channel %s", x)
+ return false
+ }
+ if elem != nil && !Identical(ch.elem, elem) {
+ check.invalidOp(x, _Todo, "channels of %s must have the same element type", x)
+ return false
+ }
+ elem = ch.elem
+ return true
+ }) {
x.mode = invalid
return
}
x.mode = commaok
- x.typ = typ.elem
+ x.typ = elem
check.hasCallOrRecv = true
return
}
@@ -622,7 +640,7 @@ func (check *Checker) implicitTypeAndValue(x *operand, target Type) (Type, const
return x.typ, nil, 0
}
- switch t := optype(target).(type) {
+ switch t := under(target).(type) {
case *Basic:
if x.mode == constant_ {
v, code := check.representation(x, t)
@@ -661,8 +679,8 @@ func (check *Checker) implicitTypeAndValue(x *operand, target Type) (Type, const
default:
return nil, nil, _InvalidUntypedConversion
}
- case *_Sum:
- ok := t.is(func(t Type) bool {
+ case *TypeParam:
+ ok := t.underIs(func(t Type) bool {
target, _, _ := check.implicitTypeAndValue(x, t)
return target != nil
})
@@ -682,7 +700,6 @@ func (check *Checker) implicitTypeAndValue(x *operand, target Type) (Type, const
return Typ[UntypedNil], nil, 0
}
// cannot assign untyped values to non-empty interfaces
- check.completeInterface(token.NoPos, t)
if !t.Empty() {
return nil, nil, _InvalidUntypedConversion
}
@@ -943,14 +960,28 @@ func (check *Checker) binary(x *operand, e ast.Expr, lhs, rhs ast.Expr, op token
return
}
- check.convertUntyped(x, y.typ)
- if x.mode == invalid {
- return
+ canMix := func(x, y *operand) bool {
+ if IsInterface(x.typ) || IsInterface(y.typ) {
+ return true
+ }
+ if isBoolean(x.typ) != isBoolean(y.typ) {
+ return false
+ }
+ if isString(x.typ) != isString(y.typ) {
+ return false
+ }
+ return true
}
- check.convertUntyped(&y, x.typ)
- if y.mode == invalid {
- x.mode = invalid
- return
+ if canMix(x, &y) {
+ check.convertUntyped(x, y.typ)
+ if x.mode == invalid {
+ return
+ }
+ check.convertUntyped(&y, x.typ)
+ if y.mode == invalid {
+ x.mode = invalid
+ return
+ }
}
if isComparison(op) {
@@ -958,7 +989,7 @@ func (check *Checker) binary(x *operand, e ast.Expr, lhs, rhs ast.Expr, op token
return
}
- if !check.identical(x.typ, y.typ) {
+ if !Identical(x.typ, y.typ) {
// only report an error if we have valid types
// (otherwise we had an error reported elsewhere already)
if x.typ != Typ[Invalid] && y.typ != Typ[Invalid] {
@@ -1154,7 +1185,7 @@ func (check *Checker) exprInternal(x *operand, e ast.Expr, hint Type) exprKind {
goto Error
}
- switch utyp := optype(base).(type) {
+ switch utyp := under(base).(type) {
case *Struct:
if len(e.Elts) == 0 {
break
@@ -1284,7 +1315,7 @@ func (check *Checker) exprInternal(x *operand, e ast.Expr, hint Type) exprKind {
xkey := keyVal(x.val)
if asInterface(utyp.key) != nil {
for _, vtyp := range visited[xkey] {
- if check.identical(vtyp, x.typ) {
+ if Identical(vtyp, x.typ) {
duplicate = true
break
}
@@ -1333,9 +1364,10 @@ func (check *Checker) exprInternal(x *operand, e ast.Expr, hint Type) exprKind {
case *ast.SelectorExpr:
check.selector(x, e)
- case *ast.IndexExpr:
- if check.indexExpr(x, e) {
- check.funcInst(x, e)
+ case *ast.IndexExpr, *ast.MultiIndexExpr:
+ ix := typeparams.UnpackIndexExpr(e)
+ if check.indexExpr(x, ix) {
+ check.funcInst(x, ix)
}
if x.mode == invalid {
goto Error
@@ -1384,13 +1416,24 @@ func (check *Checker) exprInternal(x *operand, e ast.Expr, hint Type) exprKind {
case typexpr:
x.typ = &Pointer{base: x.typ}
default:
- if typ := asPointer(x.typ); typ != nil {
- x.mode = variable
- x.typ = typ.base
- } else {
- check.invalidOp(x, _InvalidIndirection, "cannot indirect %s", x)
+ var base Type
+ if !underIs(x.typ, func(u Type) bool {
+ p, _ := u.(*Pointer)
+ if p == nil {
+ check.invalidOp(x, _InvalidIndirection, "cannot indirect %s", x)
+ return false
+ }
+ if base != nil && !Identical(p.base, base) {
+ check.invalidOp(x, _Todo, "pointers of %s must have identical base types", x)
+ return false
+ }
+ base = p.base
+ return true
+ }) {
goto Error
}
+ x.mode = variable
+ x.typ = base
}
case *ast.UnaryExpr:
@@ -1425,12 +1468,7 @@ func (check *Checker) exprInternal(x *operand, e ast.Expr, hint Type) exprKind {
// types, which are comparatively rare.
default:
- if typeparams.IsListExpr(e) {
- // catch-all for unexpected expression lists
- check.errorf(e, _Todo, "unexpected list of expressions")
- } else {
- panic(fmt.Sprintf("%s: unknown expression type %T", check.fset.Position(e.Pos()), e))
- }
+ panic(fmt.Sprintf("%s: unknown expression type %T", check.fset.Position(e.Pos()), e))
}
// everything went well
@@ -1475,7 +1513,7 @@ func (check *Checker) typeAssertion(at positioner, x *operand, xtyp *Interface,
}
var msg string
if wrongType != nil {
- if check.identical(method.typ, wrongType.typ) {
+ if Identical(method.typ, wrongType.typ) {
msg = fmt.Sprintf("missing method %s (%s has pointer receiver)", method.name, method.name)
} else {
msg = fmt.Sprintf("wrong type for method %s (have %s, want %s)", method.name, wrongType.typ, method.typ)
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