go/types, types2: mechanically swap x.mode() == invalid for !x.isValid()

Change-Id: I2e98178a42ad225aa3803dc4ccd26d50938f29b7
Reviewed-on: https://go-review.googlesource.com/c/go/+/742501
Reviewed-by: Robert Griesemer <gri@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Mark Freeman <markfreeman@google.com>

22 files changed, 140 insertions, 140 deletions

diff --git a/src/cmd/compile/internal/types2/assignments.go b/src/cmd/compile/internal/types2/assignments.go
index bd188d51da..f4ad4938ac 100644
--- a/src/cmd/compile/internal/types2/assignments.go
+++ b/src/cmd/compile/internal/types2/assignments.go
@@ -116,7 +116,7 @@ func (check *Checker) assignment(x *operand, T Type, context string) {
 }
 
 func (check *Checker) initConst(lhs *Const, x *operand) {
-	if x.mode() == invalid || !isValid(x.typ()) || !isValid(lhs.typ) {
+	if !x.isValid() || !isValid(x.typ()) || !isValid(lhs.typ) {
 		if lhs.typ == nil {
 			lhs.typ = Typ[Invalid]
 		}
@@ -139,7 +139,7 @@ func (check *Checker) initConst(lhs *Const, x *operand) {
 	}
 
 	check.assignment(x, lhs.typ, "constant declaration")
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return
 	}
 
@@ -151,7 +151,7 @@ func (check *Checker) initConst(lhs *Const, x *operand) {
 // or Typ[Invalid] in case of an error.
 // If the initialization check fails, x.mode is set to invalid.
 func (check *Checker) initVar(lhs *Var, x *operand, context string) {
-	if x.mode() == invalid || !isValid(x.typ()) || !isValid(lhs.typ) {
+	if !x.isValid() || !isValid(x.typ()) || !isValid(lhs.typ) {
 		if lhs.typ == nil {
 			lhs.typ = Typ[Invalid]
 		}
@@ -216,7 +216,7 @@ func (check *Checker) lhsVar(lhs syntax.Expr) Type {
 		check.usedVars[v] = v_used // restore v.used
 	}
 
-	if x.mode() == invalid || !isValid(x.typ()) {
+	if !x.isValid() || !isValid(x.typ()) {
 		return Typ[Invalid]
 	}
 
diff --git a/src/cmd/compile/internal/types2/builtins.go b/src/cmd/compile/internal/types2/builtins.go
index c975767fc6..45b0f41a5e 100644
--- a/src/cmd/compile/internal/types2/builtins.go
+++ b/src/cmd/compile/internal/types2/builtins.go
@@ -53,7 +53,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 		args = check.exprList(argList)
 		nargs = len(args)
 		for _, a := range args {
-			if a.mode() == invalid {
+			if !a.isValid() {
 				return
 			}
 		}
@@ -312,7 +312,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 				// and check below
 			}
 		}
-		if x.mode() == invalid || y.mode() == invalid {
+		if !x.isValid() || !y.isValid() {
 			return
 		}
 
@@ -438,7 +438,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 
 		*x = *args[1] // key
 		check.assignment(x, key, "argument to delete")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -466,7 +466,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 				// result in an error (shift of complex value)
 				check.convertUntyped(x, Typ[Complex128])
 				// x should be invalid now, but be conservative and check
-				if x.mode() == invalid {
+				if !x.isValid() {
 					return
 				}
 			}
@@ -585,7 +585,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 		}
 
 		for i, a := range args {
-			if a.mode() == invalid {
+			if !a.isValid() {
 				return
 			}
 
@@ -597,7 +597,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 			// The first argument is already in x and there's nothing left to do.
 			if i > 0 {
 				check.matchTypes(x, a)
-				if x.mode() == invalid {
+				if !x.isValid() {
 					return
 				}
 
@@ -621,7 +621,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 			x.mode_ = value
 			// A value must not be untyped.
 			check.assignment(x, &emptyInterface, "argument to built-in "+bin.name)
-			if x.mode() == invalid {
+			if !x.isValid() {
 				return
 			}
 		}
@@ -656,7 +656,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 			if isUntyped(x.typ()) {
 				// check for overflow and untyped nil
 				check.assignment(x, nil, "argument to new")
-				if x.mode() == invalid {
+				if !x.isValid() {
 					return
 				}
 				assert(isTyped(x.typ()))
@@ -688,7 +688,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 		}
 
 		check.assignment(x, &emptyInterface, "argument to panic")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -705,7 +705,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 			params = make([]Type, nargs)
 			for i, a := range args {
 				check.assignment(a, nil, "argument to built-in "+predeclaredFuncs[id].name)
-				if a.mode() == invalid {
+				if !a.isValid() {
 					return
 				}
 				params[i] = a.typ()
@@ -730,7 +730,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 		check.verifyVersionf(call.Fun, go1_17, "unsafe.Add")
 
 		check.assignment(x, Typ[UnsafePointer], "argument to unsafe.Add")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -748,7 +748,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 	case _Alignof:
 		// unsafe.Alignof(x T) uintptr
 		check.assignment(x, nil, "argument to unsafe.Alignof")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -776,7 +776,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 		}
 
 		check.expr(nil, x, selx.X)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -836,7 +836,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 	case _Sizeof:
 		// unsafe.Sizeof(x T) uintptr
 		check.assignment(x, nil, "argument to unsafe.Sizeof")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -901,7 +901,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 		check.verifyVersionf(call.Fun, go1_20, "unsafe.String")
 
 		check.assignment(x, NewPointer(universeByte), "argument to unsafe.String")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -921,7 +921,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 		check.verifyVersionf(call.Fun, go1_20, "unsafe.StringData")
 
 		check.assignment(x, Typ[String], "argument to unsafe.StringData")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -967,7 +967,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 			check.dump("%v: %s", atPos(x1), x1)
 			x1 = &t // use incoming x only for first argument
 		}
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 		// trace is only available in test mode - no need to record signature
@@ -976,7 +976,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 		panic("unreachable")
 	}
 
-	assert(x.mode() != invalid)
+	assert(x.isValid())
 	return true
 }
 
diff --git a/src/cmd/compile/internal/types2/call.go b/src/cmd/compile/internal/types2/call.go
index 467dc37609..21f929642a 100644
--- a/src/cmd/compile/internal/types2/call.go
+++ b/src/cmd/compile/internal/types2/call.go
@@ -194,7 +194,7 @@ func (check *Checker) callExpr(x *operand, call *syntax.CallExpr) exprKind {
 	case typexpr:
 		// conversion
 		check.nonGeneric(nil, x)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return conversion
 		}
 		T := x.typ()
@@ -209,7 +209,7 @@ func (check *Checker) callExpr(x *operand, call *syntax.CallExpr) exprKind {
 			check.errorf(call, WrongArgCount, "missing argument in conversion to %s", T)
 		case 1:
 			check.expr(nil, x, call.ArgList[0])
-			if x.mode() != invalid {
+			if x.isValid() {
 				if t, _ := T.Underlying().(*Interface); t != nil && !isTypeParam(T) {
 					if !t.IsMethodSet() {
 						check.errorf(call, MisplacedConstraintIface, "cannot use interface %s in conversion (contains specific type constraints or is comparable)", T)
@@ -237,7 +237,7 @@ func (check *Checker) callExpr(x *operand, call *syntax.CallExpr) exprKind {
 		}
 		x.expr = call
 		// a non-constant result implies a function call
-		if x.mode() != invalid && x.mode() != constant_ {
+		if x.isValid() && x.mode() != constant_ {
 			check.hasCallOrRecv = true
 		}
 		return predeclaredFuncs[id].kind
@@ -417,7 +417,7 @@ func (check *Checker) genericExprList(elist []syntax.Expr) (resList []*operand,
 			// x is not a function instantiation (it may still be a generic function).
 			check.rawExpr(nil, &x, e, nil, true)
 			check.exclude(&x, 1<<novalue|1<<builtin|1<<typexpr)
-			if t, ok := x.typ().(*Tuple); ok && x.mode() != invalid {
+			if t, ok := x.typ().(*Tuple); ok && x.isValid() {
 				// x is a function call returning multiple values; it cannot be generic.
 				resList = make([]*operand, t.Len())
 				for i, v := range t.vars {
@@ -1001,5 +1001,5 @@ func (check *Checker) use1(e syntax.Expr, lhs bool) bool {
 	default:
 		check.rawExpr(nil, &x, e, nil, true)
 	}
-	return x.mode() != invalid
+	return x.isValid()
 }
diff --git a/src/cmd/compile/internal/types2/expr.go b/src/cmd/compile/internal/types2/expr.go
index b092e74b0f..4f2f6b4431 100644
--- a/src/cmd/compile/internal/types2/expr.go
+++ b/src/cmd/compile/internal/types2/expr.go
@@ -129,7 +129,7 @@ var op2str2 = [...]string{
 
 func (check *Checker) unary(x *operand, e *syntax.Operation) {
 	check.expr(nil, x, e.X)
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return
 	}
 
@@ -387,7 +387,7 @@ func (check *Checker) updateExprType(x syntax.Expr, typ Type, final bool) {
 		// If x is a constant, it must be representable as a value of typ.
 		c := operand{old.mode, x, old.typ, old.val, 0}
 		check.convertUntyped(&c, typ)
-		if c.mode() == invalid {
+		if !c.isValid() {
 			return
 		}
 	}
@@ -411,7 +411,7 @@ func (check *Checker) updateExprVal(x syntax.Expr, val constant.Value) {
 // If x is a constant operand, the returned constant.Value will be the
 // representation of x in this context.
 func (check *Checker) implicitTypeAndValue(x *operand, target Type) (Type, constant.Value, Code) {
-	if x.mode() == invalid || isTyped(x.typ()) || !isValid(target) {
+	if !x.isValid() || isTyped(x.typ()) || !isValid(target) {
 		return x.typ(), nil, 0
 	}
 	// x is untyped
@@ -663,7 +663,7 @@ func (check *Checker) shift(x, y *operand, e syntax.Expr, op syntax.Operator) {
 			// Caution: Check for representability here, rather than in the switch
 			// below, because isInteger includes untyped integers (was bug go.dev/issue/43697).
 			check.representable(y, Typ[Uint])
-			if y.mode() == invalid {
+			if !y.isValid() {
 				x.invalidate()
 				return
 			}
@@ -680,7 +680,7 @@ func (check *Checker) shift(x, y *operand, e syntax.Expr, op syntax.Operator) {
 			// This is incorrect, but preserves pre-existing behavior.
 			// See also go.dev/issue/47410.
 			check.convertUntyped(y, Typ[Uint])
-			if y.mode() == invalid {
+			if !y.isValid() {
 				x.invalidate()
 				return
 			}
@@ -794,10 +794,10 @@ func (check *Checker) binary(x *operand, e syntax.Expr, lhs, rhs syntax.Expr, op
 	check.expr(nil, x, lhs)
 	check.expr(nil, &y, rhs)
 
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return
 	}
-	if y.mode() == invalid {
+	if !y.isValid() {
 		x.invalidate()
 		x.expr = y.expr
 		return
@@ -809,7 +809,7 @@ func (check *Checker) binary(x *operand, e syntax.Expr, lhs, rhs syntax.Expr, op
 	}
 
 	check.matchTypes(x, &y)
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return
 	}
 
@@ -932,11 +932,11 @@ func (check *Checker) matchTypes(x, y *operand) {
 
 	if mayConvert(x, y) {
 		check.convertUntyped(x, y.typ())
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 		check.convertUntyped(y, x.typ())
-		if y.mode() == invalid {
+		if !y.isValid() {
 			x.invalidate()
 			return
 		}
@@ -1003,7 +1003,7 @@ func (check *Checker) rawExpr(T *target, x *operand, e syntax.Expr, hint Type, a
 // from a non-nil target T, nonGeneric reports an error and invalidates x.mode and x.typ.
 // Otherwise it leaves x alone.
 func (check *Checker) nonGeneric(T *target, x *operand) {
-	if x.mode() == invalid || x.mode() == novalue {
+	if !x.isValid() || x.mode() == novalue {
 		return
 	}
 	var what string
@@ -1057,19 +1057,19 @@ func (check *Checker) exprInternal(T *target, x *operand, e syntax.Expr, hint Ty
 			goto Error // error reported during parsing
 		}
 		check.basicLit(x, e)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 
 	case *syntax.FuncLit:
 		check.funcLit(x, e)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 
 	case *syntax.CompositeLit:
 		check.compositeLit(x, e, hint)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 
@@ -1089,19 +1089,19 @@ func (check *Checker) exprInternal(T *target, x *operand, e syntax.Expr, hint Ty
 			}
 			check.funcInst(T, e.Pos(), x, e, true)
 		}
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 
 	case *syntax.SliceExpr:
 		check.sliceExpr(x, e)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 
 	case *syntax.AssertExpr:
 		check.expr(nil, x, e.X)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 		// x.(type) expressions are encoded via TypeSwitchGuards
@@ -1203,7 +1203,7 @@ func (check *Checker) exprInternal(T *target, x *operand, e syntax.Expr, hint Ty
 			}
 
 			check.unary(x, e)
-			if x.mode() == invalid {
+			if !x.isValid() {
 				goto Error
 			}
 			if e.Op == syntax.Recv {
@@ -1215,7 +1215,7 @@ func (check *Checker) exprInternal(T *target, x *operand, e syntax.Expr, hint Ty
 
 		// binary expression
 		check.binary(x, e, e.X, e.Y, e.Op)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 
@@ -1333,7 +1333,7 @@ func (check *Checker) multiExpr(e syntax.Expr, allowCommaOk bool) (list []*opera
 	check.rawExpr(nil, &x, e, nil, false)
 	check.exclude(&x, 1<<novalue|1<<builtin|1<<typexpr)
 
-	if t, ok := x.typ().(*Tuple); ok && x.mode() != invalid {
+	if t, ok := x.typ().(*Tuple); ok && x.isValid() {
 		// multiple values
 		list = make([]*operand, t.Len())
 		for i, v := range t.vars {
diff --git a/src/cmd/compile/internal/types2/index.go b/src/cmd/compile/internal/types2/index.go
index 054def5402..fd92bef2cb 100644
--- a/src/cmd/compile/internal/types2/index.go
+++ b/src/cmd/compile/internal/types2/index.go
@@ -43,7 +43,7 @@ func (check *Checker) indexExpr(x *operand, e *syntax.IndexExpr) (isFuncInst boo
 
 	// x should not be generic at this point, but be safe and check
 	check.nonGeneric(nil, x)
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return false
 	}
 
@@ -230,7 +230,7 @@ func (check *Checker) indexExpr(x *operand, e *syntax.IndexExpr) (isFuncInst boo
 
 func (check *Checker) sliceExpr(x *operand, e *syntax.SliceExpr) {
 	check.expr(nil, x, e.X)
-	if x.mode() == invalid {
+	if !x.isValid() {
 		check.use(e.Index[:]...)
 		return
 	}
@@ -451,13 +451,13 @@ func (check *Checker) index(index syntax.Expr, max int64) (typ Type, val int64)
 // If the operand is not valid, an error is reported (using what as context)
 // and the result is false.
 func (check *Checker) isValidIndex(x *operand, code Code, what string, allowNegative bool) bool {
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return false
 	}
 
 	// spec: "a constant index that is untyped is given type int"
 	check.convertUntyped(x, Typ[Int])
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return false
 	}
 
diff --git a/src/cmd/compile/internal/types2/infer.go b/src/cmd/compile/internal/types2/infer.go
index 3aeace192e..c57289622f 100644
--- a/src/cmd/compile/internal/types2/infer.go
+++ b/src/cmd/compile/internal/types2/infer.go
@@ -62,7 +62,7 @@ func (check *Checker) infer(pos syntax.Pos, tparams []*TypeParam, targs []Type,
 	// If we have invalid (ordinary) arguments, an error was reported before.
 	// Avoid additional inference errors and exit early (go.dev/issue/60434).
 	for _, arg := range args {
-		if arg.mode() == invalid {
+		if !arg.isValid() {
 			return nil
 		}
 	}
@@ -162,7 +162,7 @@ func (check *Checker) infer(pos syntax.Pos, tparams []*TypeParam, targs []Type,
 	}
 
 	for i, arg := range args {
-		if arg.mode() == invalid {
+		if !arg.isValid() {
 			// An error was reported earlier. Ignore this arg
 			// and continue, we may still be able to infer all
 			// targs resulting in fewer follow-on errors.
diff --git a/src/cmd/compile/internal/types2/literals.go b/src/cmd/compile/internal/types2/literals.go
index e33efd93ea..04a138c55b 100644
--- a/src/cmd/compile/internal/types2/literals.go
+++ b/src/cmd/compile/internal/types2/literals.go
@@ -62,7 +62,7 @@ func (check *Checker) basicLit(x *operand, e *syntax.BasicLit) {
 		}
 	}
 	x.setConst(e.Kind, e.Value)
-	if x.mode() == invalid {
+	if !x.isValid() {
 		// The parser already establishes syntactic correctness.
 		// If we reach here it's because of number under-/overflow.
 		// TODO(gri) setConst (and in turn the go/constant package)
@@ -261,7 +261,7 @@ func (check *Checker) compositeLit(x *operand, e *syntax.CompositeLit, hint Type
 			}
 			check.exprWithHint(x, kv.Key, utyp.key)
 			check.assignment(x, utyp.key, "map literal")
-			if x.mode() == invalid {
+			if !x.isValid() {
 				continue
 			}
 			if x.mode() == constant_ {
diff --git a/src/cmd/compile/internal/types2/operand.go b/src/cmd/compile/internal/types2/operand.go
index 83066c0e30..0e8aa24163 100644
--- a/src/cmd/compile/internal/types2/operand.go
+++ b/src/cmd/compile/internal/types2/operand.go
@@ -322,7 +322,7 @@ func (x *operand) isNil() bool {
 // if assignableTo is invoked through an exported API call, i.e., when all
 // methods have been type-checked.
 func (x *operand) assignableTo(check *Checker, T Type, cause *string) (bool, Code) {
-	if x.mode() == invalid || !isValid(T) {
+	if !x.isValid() || !isValid(T) {
 		return true, 0 // avoid spurious errors
 	}
 
diff --git a/src/cmd/compile/internal/types2/range.go b/src/cmd/compile/internal/types2/range.go
index 1135066af8..ae6524d0e4 100644
--- a/src/cmd/compile/internal/types2/range.go
+++ b/src/cmd/compile/internal/types2/range.go
@@ -34,7 +34,7 @@ func (check *Checker) rangeStmt(inner stmtContext, rangeStmt *syntax.ForStmt, no
 	check.hasCallOrRecv = false
 	check.expr(nil, &x, rangeVar)
 
-	if isTypes2 && x.mode() != invalid && sValue == nil && !check.hasCallOrRecv {
+	if isTypes2 && x.isValid() && sValue == nil && !check.hasCallOrRecv {
 		if t, ok := arrayPtrDeref(x.typ().Underlying()).(*Array); ok {
 			for {
 				// Put constant info on the thing inside parentheses.
@@ -61,7 +61,7 @@ func (check *Checker) rangeStmt(inner stmtContext, rangeStmt *syntax.ForStmt, no
 
 	// determine key/value types
 	var key, val Type
-	if x.mode() != invalid {
+	if x.isValid() {
 		k, v, cause, ok := rangeKeyVal(check, x.typ(), func(v goVersion) bool {
 			return check.allowVersion(v)
 		})
@@ -169,7 +169,7 @@ func (check *Checker) rangeStmt(inner stmtContext, rangeStmt *syntax.ForStmt, no
 				// If the assignment succeeded, if x was untyped before, it now
 				// has a type inferred via the assignment. It must be an integer.
 				// (go.dev/issues/67027)
-				if x.mode() != invalid && !isInteger(x.typ()) {
+				if x.isValid() && !isInteger(x.typ()) {
 					check.softErrorf(lhs, InvalidRangeExpr, "cannot use iteration variable of type %s", x.typ())
 				}
 			} else {
diff --git a/src/cmd/compile/internal/types2/stmt.go b/src/cmd/compile/internal/types2/stmt.go
index 1da8afb238..1c373299e3 100644
--- a/src/cmd/compile/internal/types2/stmt.go
+++ b/src/cmd/compile/internal/types2/stmt.go
@@ -238,17 +238,17 @@ L:
 	for _, e := range values {
 		var v operand
 		check.expr(nil, &v, e)
-		if x.mode() == invalid || v.mode() == invalid {
+		if !x.isValid() || !v.isValid() {
 			continue L
 		}
 		check.convertUntyped(&v, x.typ())
-		if v.mode() == invalid {
+		if !v.isValid() {
 			continue L
 		}
 		// Order matters: By comparing v against x, error positions are at the case values.
 		res := v // keep original v unchanged
 		check.comparison(&res, x, syntax.Eql, true)
-		if res.mode() == invalid {
+		if !res.isValid() {
 			continue L
 		}
 		if v.mode() != constant_ {
@@ -464,7 +464,7 @@ func (check *Checker) stmt(ctxt stmtContext, s syntax.Stmt) {
 		var ch, val operand
 		check.expr(nil, &ch, s.Chan)
 		check.expr(nil, &val, s.Value)
-		if ch.mode() == invalid || val.mode() == invalid {
+		if !ch.isValid() || !val.isValid() {
 			return
 		}
 		if elem := check.chanElem(s, &ch, false); elem != nil {
@@ -477,7 +477,7 @@ func (check *Checker) stmt(ctxt stmtContext, s syntax.Stmt) {
 			// (no need to call unpackExpr as s.Lhs must be single-valued)
 			var x operand
 			check.expr(nil, &x, s.Lhs)
-			if x.mode() == invalid {
+			if !x.isValid() {
 				return
 			}
 			if !allNumeric(x.typ()) {
@@ -592,7 +592,7 @@ func (check *Checker) stmt(ctxt stmtContext, s syntax.Stmt) {
 		check.simpleStmt(s.Init)
 		var x operand
 		check.expr(nil, &x, s.Cond)
-		if x.mode() != invalid && !allBoolean(x.typ()) {
+		if x.isValid() && !allBoolean(x.typ()) {
 			check.error(s.Cond, InvalidCond, "non-boolean condition in if statement")
 		}
 		check.stmt(inner, s.Then)
@@ -694,7 +694,7 @@ func (check *Checker) stmt(ctxt stmtContext, s syntax.Stmt) {
 		if s.Cond != nil {
 			var x operand
 			check.expr(nil, &x, s.Cond)
-			if x.mode() != invalid && !allBoolean(x.typ()) {
+			if x.isValid() && !allBoolean(x.typ()) {
 				check.error(s.Cond, InvalidCond, "non-boolean condition in for statement")
 			}
 		}
@@ -721,7 +721,7 @@ func (check *Checker) switchStmt(inner stmtContext, s *syntax.SwitchStmt) {
 		// By checking assignment of x to an invisible temporary
 		// (as a compiler would), we get all the relevant checks.
 		check.assignment(&x, nil, "switch expression")
-		if x.mode() != invalid && !Comparable(x.typ()) && !hasNil(x.typ()) {
+		if x.isValid() && !Comparable(x.typ()) && !hasNil(x.typ()) {
 			check.errorf(&x, InvalidExprSwitch, "cannot switch on %s (%s is not comparable)", &x, x.typ())
 			x.invalidate()
 		}
@@ -785,7 +785,7 @@ func (check *Checker) typeSwitchStmt(inner stmtContext, s *syntax.SwitchStmt, gu
 	{
 		var x operand
 		check.expr(nil, &x, guard.X)
-		if x.mode() != invalid {
+		if x.isValid() {
 			if isTypeParam(x.typ()) {
 				check.errorf(&x, InvalidTypeSwitch, "cannot use type switch on type parameter value %s", &x)
 			} else if IsInterface(x.typ()) {
diff --git a/src/cmd/compile/internal/types2/typexpr.go b/src/cmd/compile/internal/types2/typexpr.go
index 8453e2d5eb..bffc9ba684 100644
--- a/src/cmd/compile/internal/types2/typexpr.go
+++ b/src/cmd/compile/internal/types2/typexpr.go
@@ -483,7 +483,7 @@ func (check *Checker) arrayLength(e syntax.Expr) int64 {
 	var x operand
 	check.expr(nil, &x, e)
 	if x.mode() != constant_ {
-		if x.mode() != invalid {
+		if x.isValid() {
 			check.errorf(&x, InvalidArrayLen, "array length %s must be constant", &x)
 		}
 		return -1
diff --git a/src/go/types/assignments.go b/src/go/types/assignments.go
index 5655ea0b10..fcb39e3223 100644
--- a/src/go/types/assignments.go
+++ b/src/go/types/assignments.go
@@ -119,7 +119,7 @@ func (check *Checker) assignment(x *operand, T Type, context string) {
 }
 
 func (check *Checker) initConst(lhs *Const, x *operand) {
-	if x.mode() == invalid || !isValid(x.typ()) || !isValid(lhs.typ) {
+	if !x.isValid() || !isValid(x.typ()) || !isValid(lhs.typ) {
 		if lhs.typ == nil {
 			lhs.typ = Typ[Invalid]
 		}
@@ -142,7 +142,7 @@ func (check *Checker) initConst(lhs *Const, x *operand) {
 	}
 
 	check.assignment(x, lhs.typ, "constant declaration")
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return
 	}
 
@@ -154,7 +154,7 @@ func (check *Checker) initConst(lhs *Const, x *operand) {
 // or Typ[Invalid] in case of an error.
 // If the initialization check fails, x.mode is set to invalid.
 func (check *Checker) initVar(lhs *Var, x *operand, context string) {
-	if x.mode() == invalid || !isValid(x.typ()) || !isValid(lhs.typ) {
+	if !x.isValid() || !isValid(x.typ()) || !isValid(lhs.typ) {
 		if lhs.typ == nil {
 			lhs.typ = Typ[Invalid]
 		}
@@ -219,7 +219,7 @@ func (check *Checker) lhsVar(lhs ast.Expr) Type {
 		check.usedVars[v] = v_used // restore v.used
 	}
 
-	if x.mode() == invalid || !isValid(x.typ()) {
+	if !x.isValid() || !isValid(x.typ()) {
 		return Typ[Invalid]
 	}
 
diff --git a/src/go/types/builtins.go b/src/go/types/builtins.go
index 1f55368826..7f7b07166a 100644
--- a/src/go/types/builtins.go
+++ b/src/go/types/builtins.go
@@ -56,7 +56,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 		args = check.exprList(argList)
 		nargs = len(args)
 		for _, a := range args {
-			if a.mode() == invalid {
+			if !a.isValid() {
 				return
 			}
 		}
@@ -315,7 +315,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 				// and check below
 			}
 		}
-		if x.mode() == invalid || y.mode() == invalid {
+		if !x.isValid() || !y.isValid() {
 			return
 		}
 
@@ -441,7 +441,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 
 		*x = *args[1] // key
 		check.assignment(x, key, "argument to delete")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -469,7 +469,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 				// result in an error (shift of complex value)
 				check.convertUntyped(x, Typ[Complex128])
 				// x should be invalid now, but be conservative and check
-				if x.mode() == invalid {
+				if !x.isValid() {
 					return
 				}
 			}
@@ -588,7 +588,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 		}
 
 		for i, a := range args {
-			if a.mode() == invalid {
+			if !a.isValid() {
 				return
 			}
 
@@ -600,7 +600,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 			// The first argument is already in x and there's nothing left to do.
 			if i > 0 {
 				check.matchTypes(x, a)
-				if x.mode() == invalid {
+				if !x.isValid() {
 					return
 				}
 
@@ -624,7 +624,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 			x.mode_ = value
 			// A value must not be untyped.
 			check.assignment(x, &emptyInterface, "argument to built-in "+bin.name)
-			if x.mode() == invalid {
+			if !x.isValid() {
 				return
 			}
 		}
@@ -659,7 +659,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 			if isUntyped(x.typ()) {
 				// check for overflow and untyped nil
 				check.assignment(x, nil, "argument to new")
-				if x.mode() == invalid {
+				if !x.isValid() {
 					return
 				}
 				assert(isTyped(x.typ()))
@@ -691,7 +691,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 		}
 
 		check.assignment(x, &emptyInterface, "argument to panic")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -708,7 +708,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 			params = make([]Type, nargs)
 			for i, a := range args {
 				check.assignment(a, nil, "argument to built-in "+predeclaredFuncs[id].name)
-				if a.mode() == invalid {
+				if !a.isValid() {
 					return
 				}
 				params[i] = a.typ()
@@ -733,7 +733,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 		check.verifyVersionf(call.Fun, go1_17, "unsafe.Add")
 
 		check.assignment(x, Typ[UnsafePointer], "argument to unsafe.Add")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -751,7 +751,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 	case _Alignof:
 		// unsafe.Alignof(x T) uintptr
 		check.assignment(x, nil, "argument to unsafe.Alignof")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -779,7 +779,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 		}
 
 		check.expr(nil, x, selx.X)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -839,7 +839,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 	case _Sizeof:
 		// unsafe.Sizeof(x T) uintptr
 		check.assignment(x, nil, "argument to unsafe.Sizeof")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -904,7 +904,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 		check.verifyVersionf(call.Fun, go1_20, "unsafe.String")
 
 		check.assignment(x, NewPointer(universeByte), "argument to unsafe.String")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -924,7 +924,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 		check.verifyVersionf(call.Fun, go1_20, "unsafe.StringData")
 
 		check.assignment(x, Typ[String], "argument to unsafe.StringData")
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 
@@ -970,7 +970,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 			check.dump("%v: %s", x1.Pos(), x1)
 			x1 = &t // use incoming x only for first argument
 		}
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 		// trace is only available in test mode - no need to record signature
@@ -979,7 +979,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 		panic("unreachable")
 	}
 
-	assert(x.mode() != invalid)
+	assert(x.isValid())
 	return true
 }
 
diff --git a/src/go/types/call.go b/src/go/types/call.go
index 0b8ef351db..744f246d24 100644
--- a/src/go/types/call.go
+++ b/src/go/types/call.go
@@ -196,7 +196,7 @@ func (check *Checker) callExpr(x *operand, call *ast.CallExpr) exprKind {
 	case typexpr:
 		// conversion
 		check.nonGeneric(nil, x)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return conversion
 		}
 		T := x.typ()
@@ -211,7 +211,7 @@ func (check *Checker) callExpr(x *operand, call *ast.CallExpr) exprKind {
 			check.errorf(inNode(call, call.Rparen), WrongArgCount, "missing argument in conversion to %s", T)
 		case 1:
 			check.expr(nil, x, call.Args[0])
-			if x.mode() != invalid {
+			if x.isValid() {
 				if hasDots(call) {
 					check.errorf(call.Args[0], BadDotDotDotSyntax, "invalid use of ... in conversion to %s", T)
 					break
@@ -239,7 +239,7 @@ func (check *Checker) callExpr(x *operand, call *ast.CallExpr) exprKind {
 		}
 		x.expr = call
 		// a non-constant result implies a function call
-		if x.mode() != invalid && x.mode() != constant_ {
+		if x.isValid() && x.mode() != constant_ {
 			check.hasCallOrRecv = true
 		}
 		return predeclaredFuncs[id].kind
@@ -419,7 +419,7 @@ func (check *Checker) genericExprList(elist []ast.Expr) (resList []*operand, tar
 			// x is not a function instantiation (it may still be a generic function).
 			check.rawExpr(nil, &x, e, nil, true)
 			check.exclude(&x, 1<<novalue|1<<builtin|1<<typexpr)
-			if t, ok := x.typ().(*Tuple); ok && x.mode() != invalid {
+			if t, ok := x.typ().(*Tuple); ok && x.isValid() {
 				// x is a function call returning multiple values; it cannot be generic.
 				resList = make([]*operand, t.Len())
 				for i, v := range t.vars {
@@ -1047,5 +1047,5 @@ func (check *Checker) use1(e ast.Expr, lhs bool) bool {
 	default:
 		check.rawExpr(nil, &x, e, nil, true)
 	}
-	return x.mode() != invalid
+	return x.isValid()
 }
diff --git a/src/go/types/expr.go b/src/go/types/expr.go
index 344246e741..ad8bad2fe7 100644
--- a/src/go/types/expr.go
+++ b/src/go/types/expr.go
@@ -128,7 +128,7 @@ var op2str2 = [...]string{
 // 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(nil, x, e.X)
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return
 	}
 
@@ -362,7 +362,7 @@ func (check *Checker) updateExprType(x ast.Expr, typ Type, final bool) {
 		// If x is a constant, it must be representable as a value of typ.
 		c := operand{old.mode, x, old.typ, old.val, 0}
 		check.convertUntyped(&c, typ)
-		if c.mode() == invalid {
+		if !c.isValid() {
 			return
 		}
 	}
@@ -386,7 +386,7 @@ func (check *Checker) updateExprVal(x ast.Expr, val constant.Value) {
 // If x is a constant operand, the returned constant.Value will be the
 // representation of x in this context.
 func (check *Checker) implicitTypeAndValue(x *operand, target Type) (Type, constant.Value, Code) {
-	if x.mode() == invalid || isTyped(x.typ()) || !isValid(target) {
+	if !x.isValid() || isTyped(x.typ()) || !isValid(target) {
 		return x.typ(), nil, 0
 	}
 	// x is untyped
@@ -652,7 +652,7 @@ func (check *Checker) shift(x, y *operand, e ast.Expr, op token.Token) {
 			// Caution: Check for representability here, rather than in the switch
 			// below, because isInteger includes untyped integers (was bug go.dev/issue/43697).
 			check.representable(y, Typ[Uint])
-			if y.mode() == invalid {
+			if !y.isValid() {
 				x.invalidate()
 				return
 			}
@@ -669,7 +669,7 @@ func (check *Checker) shift(x, y *operand, e ast.Expr, op token.Token) {
 			// This is incorrect, but preserves pre-existing behavior.
 			// See also go.dev/issue/47410.
 			check.convertUntyped(y, Typ[Uint])
-			if y.mode() == invalid {
+			if !y.isValid() {
 				x.invalidate()
 				return
 			}
@@ -783,10 +783,10 @@ func (check *Checker) binary(x *operand, e ast.Expr, lhs, rhs ast.Expr, op token
 	check.expr(nil, x, lhs)
 	check.expr(nil, &y, rhs)
 
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return
 	}
-	if y.mode() == invalid {
+	if !y.isValid() {
 		x.invalidate()
 		x.expr = y.expr
 		return
@@ -798,7 +798,7 @@ func (check *Checker) binary(x *operand, e ast.Expr, lhs, rhs ast.Expr, op token
 	}
 
 	check.matchTypes(x, &y)
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return
 	}
 
@@ -924,11 +924,11 @@ func (check *Checker) matchTypes(x, y *operand) {
 
 	if mayConvert(x, y) {
 		check.convertUntyped(x, y.typ())
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 		check.convertUntyped(y, x.typ())
-		if y.mode() == invalid {
+		if !y.isValid() {
 			x.invalidate()
 			return
 		}
@@ -995,7 +995,7 @@ func (check *Checker) rawExpr(T *target, x *operand, e ast.Expr, hint Type, allo
 // from a non-nil target T, nonGeneric reports an error and invalidates x.mode and x.typ.
 // Otherwise it leaves x alone.
 func (check *Checker) nonGeneric(T *target, x *operand) {
-	if x.mode() == invalid || x.mode() == novalue {
+	if !x.isValid() || x.mode() == novalue {
 		return
 	}
 	var what string
@@ -1043,19 +1043,19 @@ func (check *Checker) exprInternal(T *target, x *operand, e ast.Expr, hint Type)
 
 	case *ast.BasicLit:
 		check.basicLit(x, e)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 
 	case *ast.FuncLit:
 		check.funcLit(x, e)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 
 	case *ast.CompositeLit:
 		check.compositeLit(x, e, hint)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 
@@ -1076,19 +1076,19 @@ func (check *Checker) exprInternal(T *target, x *operand, e ast.Expr, hint Type)
 			}
 			check.funcInst(T, e.Pos(), x, ix, true)
 		}
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 
 	case *ast.SliceExpr:
 		check.sliceExpr(x, e)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 
 	case *ast.TypeAssertExpr:
 		check.expr(nil, x, e.X)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 		// x.(type) expressions are handled explicitly in type switches
@@ -1156,7 +1156,7 @@ func (check *Checker) exprInternal(T *target, x *operand, e ast.Expr, hint Type)
 
 	case *ast.UnaryExpr:
 		check.unary(x, e)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 		if e.Op == token.ARROW {
@@ -1166,7 +1166,7 @@ func (check *Checker) exprInternal(T *target, x *operand, e ast.Expr, hint Type)
 
 	case *ast.BinaryExpr:
 		check.binary(x, e, e.X, e.Y, e.Op, e.OpPos)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			goto Error
 		}
 
@@ -1284,7 +1284,7 @@ func (check *Checker) multiExpr(e ast.Expr, allowCommaOk bool) (list []*operand,
 	check.rawExpr(nil, &x, e, nil, false)
 	check.exclude(&x, 1<<novalue|1<<builtin|1<<typexpr)
 
-	if t, ok := x.typ().(*Tuple); ok && x.mode() != invalid {
+	if t, ok := x.typ().(*Tuple); ok && x.isValid() {
 		// multiple values
 		list = make([]*operand, t.Len())
 		for i, v := range t.vars {
diff --git a/src/go/types/index.go b/src/go/types/index.go
index 8a540151cb..3c8bf4ffe4 100644
--- a/src/go/types/index.go
+++ b/src/go/types/index.go
@@ -44,7 +44,7 @@ func (check *Checker) indexExpr(x *operand, e *indexedExpr) (isFuncInst bool) {
 
 	// x should not be generic at this point, but be safe and check
 	check.nonGeneric(nil, x)
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return false
 	}
 
@@ -232,7 +232,7 @@ func (check *Checker) indexExpr(x *operand, e *indexedExpr) (isFuncInst bool) {
 
 func (check *Checker) sliceExpr(x *operand, e *ast.SliceExpr) {
 	check.expr(nil, x, e.X)
-	if x.mode() == invalid {
+	if !x.isValid() {
 		check.use(e.Low, e.High, e.Max)
 		return
 	}
@@ -447,13 +447,13 @@ func (check *Checker) index(index ast.Expr, max int64) (typ Type, val int64) {
 }
 
 func (check *Checker) isValidIndex(x *operand, code Code, what string, allowNegative bool) bool {
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return false
 	}
 
 	// spec: "a constant index that is untyped is given type int"
 	check.convertUntyped(x, Typ[Int])
-	if x.mode() == invalid {
+	if !x.isValid() {
 		return false
 	}
 
diff --git a/src/go/types/infer.go b/src/go/types/infer.go
index 6a49be7079..6a7364e246 100644
--- a/src/go/types/infer.go
+++ b/src/go/types/infer.go
@@ -65,7 +65,7 @@ func (check *Checker) infer(posn positioner, tparams []*TypeParam, targs []Type,
 	// If we have invalid (ordinary) arguments, an error was reported before.
 	// Avoid additional inference errors and exit early (go.dev/issue/60434).
 	for _, arg := range args {
-		if arg.mode() == invalid {
+		if !arg.isValid() {
 			return nil
 		}
 	}
@@ -165,7 +165,7 @@ func (check *Checker) infer(posn positioner, tparams []*TypeParam, targs []Type,
 	}
 
 	for i, arg := range args {
-		if arg.mode() == invalid {
+		if !arg.isValid() {
 			// An error was reported earlier. Ignore this arg
 			// and continue, we may still be able to infer all
 			// targs resulting in fewer follow-on errors.
diff --git a/src/go/types/literals.go b/src/go/types/literals.go
index bc98ae8db0..04fe103019 100644
--- a/src/go/types/literals.go
+++ b/src/go/types/literals.go
@@ -66,7 +66,7 @@ func (check *Checker) basicLit(x *operand, e *ast.BasicLit) {
 		}
 	}
 	x.setConst(e.Kind, e.Value)
-	if x.mode() == invalid {
+	if !x.isValid() {
 		// The parser already establishes syntactic correctness.
 		// If we reach here it's because of number under-/overflow.
 		// TODO(gri) setConst (and in turn the go/constant package)
@@ -265,7 +265,7 @@ func (check *Checker) compositeLit(x *operand, e *ast.CompositeLit, hint Type) {
 			}
 			check.exprWithHint(x, kv.Key, utyp.key)
 			check.assignment(x, utyp.key, "map literal")
-			if x.mode() == invalid {
+			if !x.isValid() {
 				continue
 			}
 			if x.mode() == constant_ {
diff --git a/src/go/types/operand.go b/src/go/types/operand.go
index 66850d67d6..860611ac89 100644
--- a/src/go/types/operand.go
+++ b/src/go/types/operand.go
@@ -326,7 +326,7 @@ func (x *operand) isNil() bool {
 // if assignableTo is invoked through an exported API call, i.e., when all
 // methods have been type-checked.
 func (x *operand) assignableTo(check *Checker, T Type, cause *string) (bool, Code) {
-	if x.mode() == invalid || !isValid(T) {
+	if !x.isValid() || !isValid(T) {
 		return true, 0 // avoid spurious errors
 	}
 
diff --git a/src/go/types/range.go b/src/go/types/range.go
index 05ef827eec..208da64ba2 100644
--- a/src/go/types/range.go
+++ b/src/go/types/range.go
@@ -37,7 +37,7 @@ func (check *Checker) rangeStmt(inner stmtContext, rangeStmt *ast.RangeStmt, noN
 	check.hasCallOrRecv = false
 	check.expr(nil, &x, rangeVar)
 
-	if isTypes2 && x.mode() != invalid && sValue == nil && !check.hasCallOrRecv {
+	if isTypes2 && x.isValid() && sValue == nil && !check.hasCallOrRecv {
 		if t, ok := arrayPtrDeref(x.typ().Underlying()).(*Array); ok {
 			for {
 				// Put constant info on the thing inside parentheses.
@@ -64,7 +64,7 @@ func (check *Checker) rangeStmt(inner stmtContext, rangeStmt *ast.RangeStmt, noN
 
 	// determine key/value types
 	var key, val Type
-	if x.mode() != invalid {
+	if x.isValid() {
 		k, v, cause, ok := rangeKeyVal(check, x.typ(), func(v goVersion) bool {
 			return check.allowVersion(v)
 		})
@@ -172,7 +172,7 @@ func (check *Checker) rangeStmt(inner stmtContext, rangeStmt *ast.RangeStmt, noN
 				// If the assignment succeeded, if x was untyped before, it now
 				// has a type inferred via the assignment. It must be an integer.
 				// (go.dev/issues/67027)
-				if x.mode() != invalid && !isInteger(x.typ()) {
+				if x.isValid() && !isInteger(x.typ()) {
 					check.softErrorf(lhs, InvalidRangeExpr, "cannot use iteration variable of type %s", x.typ())
 				}
 			} else {
diff --git a/src/go/types/stmt.go b/src/go/types/stmt.go
index 773c2fd590..e856c5e712 100644
--- a/src/go/types/stmt.go
+++ b/src/go/types/stmt.go
@@ -239,17 +239,17 @@ L:
 	for _, e := range values {
 		var v operand
 		check.expr(nil, &v, e)
-		if x.mode() == invalid || v.mode() == invalid {
+		if !x.isValid() || !v.isValid() {
 			continue L
 		}
 		check.convertUntyped(&v, x.typ())
-		if v.mode() == invalid {
+		if !v.isValid() {
 			continue L
 		}
 		// Order matters: By comparing v against x, error positions are at the case values.
 		res := v // keep original v unchanged
 		check.comparison(&res, x, token.EQL, true)
-		if res.mode() == invalid {
+		if !res.isValid() {
 			continue L
 		}
 		if v.mode() != constant_ {
@@ -465,7 +465,7 @@ func (check *Checker) stmt(ctxt stmtContext, s ast.Stmt) {
 		var ch, val operand
 		check.expr(nil, &ch, s.Chan)
 		check.expr(nil, &val, s.Value)
-		if ch.mode() == invalid || val.mode() == invalid {
+		if !ch.isValid() || !val.isValid() {
 			return
 		}
 		if elem := check.chanElem(inNode(s, s.Arrow), &ch, false); elem != nil {
@@ -486,7 +486,7 @@ func (check *Checker) stmt(ctxt stmtContext, s ast.Stmt) {
 
 		var x operand
 		check.expr(nil, &x, s.X)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 		if !allNumeric(x.typ()) {
@@ -496,7 +496,7 @@ func (check *Checker) stmt(ctxt stmtContext, s ast.Stmt) {
 
 		Y := &ast.BasicLit{ValuePos: s.X.Pos(), Kind: token.INT, Value: "1"} // use x's position
 		check.binary(&x, nil, s.X, Y, op, s.TokPos)
-		if x.mode() == invalid {
+		if !x.isValid() {
 			return
 		}
 		check.assignVar(s.X, nil, &x, "assignment")
@@ -528,7 +528,7 @@ func (check *Checker) stmt(ctxt stmtContext, s ast.Stmt) {
 			}
 			var x operand
 			check.binary(&x, nil, s.Lhs[0], s.Rhs[0], op, s.TokPos)
-			if x.mode() == invalid {
+			if !x.isValid() {
 				return
 			}
 			check.assignVar(s.Lhs[0], nil, &x, "assignment")
@@ -609,7 +609,7 @@ func (check *Checker) stmt(ctxt stmtContext, s ast.Stmt) {
 		check.simpleStmt(s.Init)
 		var x operand
 		check.expr(nil, &x, s.Cond)
-		if x.mode() != invalid && !allBoolean(x.typ()) {
+		if x.isValid() && !allBoolean(x.typ()) {
 			check.error(s.Cond, InvalidCond, "non-boolean condition in if statement")
 		}
 		check.stmt(inner, s.Body)
@@ -636,7 +636,7 @@ func (check *Checker) stmt(ctxt stmtContext, s ast.Stmt) {
 			// By checking assignment of x to an invisible temporary
 			// (as a compiler would), we get all the relevant checks.
 			check.assignment(&x, nil, "switch expression")
-			if x.mode() != invalid && !Comparable(x.typ()) && !hasNil(x.typ()) {
+			if x.isValid() && !Comparable(x.typ()) && !hasNil(x.typ()) {
 				check.errorf(&x, InvalidExprSwitch, "cannot switch on %s (%s is not comparable)", &x, x.typ())
 				x.invalidate()
 			}
@@ -728,7 +728,7 @@ func (check *Checker) stmt(ctxt stmtContext, s ast.Stmt) {
 		{
 			var x operand
 			check.expr(nil, &x, expr.X)
-			if x.mode() != invalid {
+			if x.isValid() {
 				if isTypeParam(x.typ()) {
 					check.errorf(&x, InvalidTypeSwitch, "cannot use type switch on type parameter value %s", &x)
 				} else if IsInterface(x.typ()) {
@@ -837,7 +837,7 @@ func (check *Checker) stmt(ctxt stmtContext, s ast.Stmt) {
 		if s.Cond != nil {
 			var x operand
 			check.expr(nil, &x, s.Cond)
-			if x.mode() != invalid && !allBoolean(x.typ()) {
+			if x.isValid() && !allBoolean(x.typ()) {
 				check.error(s.Cond, InvalidCond, "non-boolean condition in for statement")
 			}
 		}
diff --git a/src/go/types/typexpr.go b/src/go/types/typexpr.go
index c718922572..f289844f33 100644
--- a/src/go/types/typexpr.go
+++ b/src/go/types/typexpr.go
@@ -479,7 +479,7 @@ func (check *Checker) arrayLength(e ast.Expr) int64 {
 	var x operand
 	check.expr(nil, &x, e)
 	if x.mode() != constant_ {
-		if x.mode() != invalid {
+		if x.isValid() {
 			check.errorf(&x, InvalidArrayLen, "array length %s must be constant", &x)
 		}
 		return -1