ruleguard/typematch: add interface{$*_} pattern support

analyzer/testdata/src/filtertest/f1.go

@@ -2,6 +2,7 @@ package filtertest
 
 import (
 	"errors"
+	"fmt"
 	"os"
 	"time"
 )
@@ -49,6 +50,24 @@ func assignableTo() {
 }
 
 func detectType() {
+	{
+		var s fmt.Stringer
+
+		typeTest(s, "is interface")
+		typeTest(interface{}(nil), "is interface") // want `YES`
+		typeTest(implementsAll{}, "is interface")
+		typeTest(&implementsAll{}, "is interface")
+		typeTest(4, "is interface")
+		typeTest("", "is interface")
+
+		typeTest(s, "underlying is interface")                // want `YES`
+		typeTest(interface{}(nil), "underlying is interface") // want `YES`
+		typeTest(implementsAll{}, "underlying is interface")
+		typeTest(&implementsAll{}, "underlying is interface")
+		typeTest(4, "underlying is interface")
+		typeTest("", "underlying is interface")
+	}
+
 	{
 		type withNamedTime struct {
 			x int

analyzer/testdata/src/filtertest/rules.go

@@ -137,4 +137,12 @@ func testRules(m dsl.Matcher) {
 	m.Match(`typeTest($x, "assignable to interface{}")`).
 		Where(m["x"].Type.AssignableTo(`interface{}`)).
 		Report(`YES`)
+
+	m.Match(`typeTest($x, "is interface")`).
+		Where(m["x"].Type.Is(`interface{ $*_ }`)).
+		Report(`YES`)
+
+	m.Match(`typeTest($x, "underlying is interface")`).
+		Where(m["x"].Type.Underlying().Is(`interface{ $*_ }`)).
+		Report(`YES`)
 }

ruleguard/typematch/typematch.go

@@ -27,6 +27,7 @@ const (
 	opFunc
 	opStructNoSeq
 	opStruct
+	opAnyInterface
 	opNamed
 )
 
@@ -313,6 +314,16 @@ func parseExpr(ctx *Context, e ast.Expr) *pattern {
 		if len(e.Methods.List) == 0 {
 			return &pattern{op: opBuiltinType, value: efaceType}
 		}
+		if len(e.Methods.List) == 1 {
+			p := parseExpr(ctx, e.Methods.List[0].Type)
+			if p == nil {
+				return nil
+			}
+			if p.op != opVarSeq {
+				return nil
+			}
+			return &pattern{op: opAnyInterface}
+		}
 	}
 
 	return nil
@@ -525,6 +536,10 @@ func (p *Pattern) matchIdentical(sub *pattern, typ types.Type) bool {
 		}
 		return true
 
+	case opAnyInterface:
+		_, ok := typ.(*types.Interface)
+		return ok
+
 	default:
 		return false
 	}

ruleguard/typematch/typematch_test.go

@@ -14,6 +14,11 @@ var (
 	typeUint8   = types.Typ[types.Uint8]
 	typeEstruct = types.NewStruct(nil, nil)
 
+	stringerIface = types.NewInterfaceType([]*types.Func{
+		types.NewFunc(token.NoPos, nil, "String",
+			types.NewSignature(nil, types.NewTuple(), types.NewTuple(types.NewVar(token.NoPos, nil, "result", typeString)), false)),
+	}, nil)
+
 	intVar     = types.NewVar(token.NoPos, nil, "_", typeInt)
 	int32Var   = types.NewVar(token.NoPos, nil, "_", typeInt32)
 	estructVar = types.NewVar(token.NoPos, nil, "_", typeEstruct)
@@ -55,7 +60,9 @@ func TestIdentical(t *testing.T) {
 		{`[][]int`, types.NewSlice(types.NewSlice(typeInt))},
 		{`[10]int`, types.NewArray(typeInt, 10)},
 		{`map[int]int`, types.NewMap(typeInt, typeInt)},
+
 		{`interface{}`, types.NewInterfaceType(nil, nil)},
+		{`interface{ $*_ }`, stringerIface},
 
 		{`$t`, typeInt},
 		{`*$t`, types.NewPointer(typeInt)},
@@ -159,7 +166,10 @@ func TestIdenticalNegative(t *testing.T) {
 		{`map[int]int`, types.NewMap(typeString, typeString)},
 		{`map[int]int`, types.NewMap(typeString, typeInt)},
 		{`map[int]int`, types.NewMap(typeInt, typeString)},
+
 		{`interface{}`, typeInt},
+		{`interface{ $*_ }`, typeString},
+		{`interface{ $*_ }`, types.NewArray(typeString, 10)},
 
 		{`*$t`, typeInt},
 		{`map[$t]$t`, types.NewMap(typeString, typeInt)},