diff --git a/oracle/definition.go b/oracle/definition.go
index a0340c6a4f..eaf754e10a 100644
--- a/oracle/definition.go
+++ b/oracle/definition.go
@@ -23,7 +23,7 @@ func definition(q *Query) error {
 	lconf := loader.Config{Build: q.Build}
 	allowErrors(&lconf)
 
-	if err := importQueryPackage(q.Pos, &lconf); err != nil {
+	if _, err := importQueryPackage(q.Pos, &lconf); err != nil {
 		return err
 	}
 
diff --git a/oracle/describe.go b/oracle/describe.go
index ea1c5ecf7c..db53696e06 100644
--- a/oracle/describe.go
+++ b/oracle/describe.go
@@ -31,7 +31,7 @@ func describe(q *Query) error {
 	lconf := loader.Config{Build: q.Build}
 	allowErrors(&lconf)
 
-	if err := importQueryPackage(q.Pos, &lconf); err != nil {
+	if _, err := importQueryPackage(q.Pos, &lconf); err != nil {
 		return err
 	}
 
diff --git a/oracle/freevars.go b/oracle/freevars.go
index 400a118f6b..c0937f9d87 100644
--- a/oracle/freevars.go
+++ b/oracle/freevars.go
@@ -33,7 +33,7 @@ func freevars(q *Query) error {
 	lconf := loader.Config{Build: q.Build}
 	allowErrors(&lconf)
 
-	if err := importQueryPackage(q.Pos, &lconf); err != nil {
+	if _, err := importQueryPackage(q.Pos, &lconf); err != nil {
 		return err
 	}
 
diff --git a/oracle/implements.go b/oracle/implements.go
index 3155ca29e9..bf58154e8a 100644
--- a/oracle/implements.go
+++ b/oracle/implements.go
@@ -16,10 +16,11 @@ import (
 	"golang.org/x/tools/go/types"
 	"golang.org/x/tools/go/types/typeutil"
 	"golang.org/x/tools/oracle/serial"
+	"golang.org/x/tools/refactor/importgraph"
 )
 
 // Implements displays the "implements" relation as it pertains to the
-// selected type within a single package.
+// selected type.
 // If the selection is a method, 'implements' displays
 // the corresponding methods of the types that would have been reported
 // by an implements query on the receiver type.
@@ -28,10 +29,35 @@ func implements(q *Query) error {
 	lconf := loader.Config{Build: q.Build}
 	allowErrors(&lconf)
 
-	if err := importQueryPackage(q.Pos, &lconf); err != nil {
+	qpkg, err := importQueryPackage(q.Pos, &lconf)
+	if err != nil {
 		return err
 	}
 
+	// Set the packages to search.
+	if len(q.Scope) > 0 {
+		// Inspect all packages in the analysis scope, if specified.
+		if err := setPTAScope(&lconf, q.Scope); err != nil {
+			return err
+		}
+	} else {
+		// Otherwise inspect the forward and reverse
+		// transitive closure of the selected package.
+		// (In theory even this is incomplete.)
+		_, rev, _ := importgraph.Build(q.Build)
+		for path := range rev.Search(qpkg) {
+			lconf.ImportWithTests(path)
+		}
+
+		// TODO(adonovan): for completeness, we should also
+		// type-check and inspect function bodies in all
+		// imported packages.  This would be expensive, but we
+		// could optimize by skipping functions that do not
+		// contain type declarations.  This would require
+		// changing the loader's TypeCheckFuncBodies hook to
+		// provide the []*ast.File.
+	}
+
 	// Load/parse/type-check the program.
 	lprog, err := lconf.Load()
 	if err != nil {
@@ -72,10 +98,6 @@ func implements(q *Query) error {
 
 	// Find all named types, even local types (which can have
 	// methods via promotion) and the built-in "error".
-	//
-	// TODO(adonovan): include all packages in PTA scope too?
-	// i.e. don't reduceScope?
-	//
 	var allNamed []types.Type
 	for _, info := range lprog.AllPackages {
 		for _, obj := range info.Defs {
diff --git a/oracle/oracle.go b/oracle/oracle.go
index 544cfa410f..afc50a973d 100644
--- a/oracle/oracle.go
+++ b/oracle/oracle.go
@@ -190,10 +190,11 @@ func setupPTA(prog *ssa.Program, lprog *loader.Program, ptaLog io.Writer, reflec
 
 // importQueryPackage finds the package P containing the
 // query position and tells conf to import it.
-func importQueryPackage(pos string, conf *loader.Config) error {
+// It returns the package's path.
+func importQueryPackage(pos string, conf *loader.Config) (string, error) {
 	fqpos, err := fastQueryPos(pos)
 	if err != nil {
-		return err // bad query
+		return "", err // bad query
 	}
 	filename := fqpos.fset.File(fqpos.start).Name()
 
@@ -202,10 +203,10 @@ func importQueryPackage(pos string, conf *loader.Config) error {
 	// TODO(adonovan): ensure we report a clear error.
 	_, importPath, err := guessImportPath(filename, conf.Build)
 	if err != nil {
-		return err // can't find GOPATH dir
+		return "", err // can't find GOPATH dir
 	}
 	if importPath == "" {
-		return fmt.Errorf("can't guess import path from %s", filename)
+		return "", fmt.Errorf("can't guess import path from %s", filename)
 	}
 
 	// Check that it's possible to load the queried package.
@@ -215,7 +216,7 @@ func importQueryPackage(pos string, conf *loader.Config) error {
 	cfg2.CgoEnabled = false
 	bp, err := cfg2.Import(importPath, "", 0)
 	if err != nil {
-		return err // no files for package
+		return "", err // no files for package
 	}
 
 	switch pkgContainsFile(bp, filename) {
@@ -227,13 +228,13 @@ func importQueryPackage(pos string, conf *loader.Config) error {
 	case 'G':
 		conf.Import(importPath)
 	default:
-		return fmt.Errorf("package %q doesn't contain file %s",
+		return "", fmt.Errorf("package %q doesn't contain file %s",
 			importPath, filename)
 	}
 
 	conf.TypeCheckFuncBodies = func(p string) bool { return p == importPath }
 
-	return nil
+	return importPath, nil
 }
 
 // pkgContainsFile reports whether file was among the packages Go
diff --git a/oracle/referrers.go b/oracle/referrers.go
index 7383d1f44a..12b0316268 100644
--- a/oracle/referrers.go
+++ b/oracle/referrers.go
@@ -24,7 +24,7 @@ func referrers(q *Query) error {
 	lconf := loader.Config{Build: q.Build}
 	allowErrors(&lconf)
 
-	if err := importQueryPackage(q.Pos, &lconf); err != nil {
+	if _, err := importQueryPackage(q.Pos, &lconf); err != nil {
 		return err
 	}
 
diff --git a/oracle/testdata/src/implements-methods-json/main.golden b/oracle/testdata/src/implements-methods-json/main.golden
index fa117df41f..831900a588 100644
--- a/oracle/testdata/src/implements-methods-json/main.golden
+++ b/oracle/testdata/src/implements-methods-json/main.golden
@@ -274,6 +274,18 @@
 				"name": "lib.Type",
 				"pos": "testdata/src/lib/lib.go:3:6",
 				"kind": "basic"
+			},
+			{
+				"name": "main.I",
+				"pos": "testdata/src/implements-methods-json/main.go:35:6",
+				"kind": "interface"
+			}
+		],
+		"from": [
+			{
+				"name": "main.I",
+				"pos": "testdata/src/implements-methods-json/main.go:35:6",
+				"kind": "interface"
 			}
 		],
 		"method": {
@@ -284,6 +296,16 @@
 			{
 				"name": "method (lib.Type) Method(x *int) *int",
 				"pos": "testdata/src/lib/lib.go:5:13"
+			},
+			{
+				"name": "method (main.I) Method(*int) *int",
+				"pos": "testdata/src/implements-methods-json/main.go:36:2"
+			}
+		],
+		"from_method": [
+			{
+				"name": "method (main.I) Method(*int) *int",
+				"pos": "testdata/src/implements-methods-json/main.go:36:2"
 			}
 		]
 	}
diff --git a/oracle/testdata/src/implements-methods/main.golden b/oracle/testdata/src/implements-methods/main.golden
index bd591e8476..227d305cbd 100644
--- a/oracle/testdata/src/implements-methods/main.golden
+++ b/oracle/testdata/src/implements-methods/main.golden
@@ -34,4 +34,6 @@ concrete method func (sorter).Len() int
 -------- @implements I.Method --------
 abstract method func (I).Method(*int) *int
 	is implemented by method (lib.Type).Method
+	is implemented by method (main.I).Method
+	implements method (main.I).Method
 
diff --git a/oracle/testdata/src/implements/main.golden b/oracle/testdata/src/implements/main.golden
index ee00f3d9fe..cb2f2ac57f 100644
--- a/oracle/testdata/src/implements/main.golden
+++ b/oracle/testdata/src/implements/main.golden
@@ -41,4 +41,6 @@ slice type sorter
 -------- @implements I --------
 interface type I
 	is implemented by basic type lib.Type
+	is implemented by interface type main.I
+	implements main.I