diff --git a/internal/lsp/definition.go b/internal/lsp/definition.go
index 78aae36..ab2b442 100644
--- a/internal/lsp/definition.go
+++ b/internal/lsp/definition.go
@@ -23,7 +23,7 @@
 	if err != nil {
 		return nil, err
 	}
-	ident, err := source.Identifier(ctx, snapshot, f, params.Position)
+	ident, err := source.Identifier(ctx, snapshot, f, params.Position, source.WidestCheckPackageHandle)
 	if err != nil {
 		return nil, err
 	}
@@ -50,7 +50,7 @@
 	if err != nil {
 		return nil, err
 	}
-	ident, err := source.Identifier(ctx, snapshot, f, params.Position)
+	ident, err := source.Identifier(ctx, snapshot, f, params.Position, source.WidestCheckPackageHandle)
 	if err != nil {
 		return nil, err
 	}
diff --git a/internal/lsp/hover.go b/internal/lsp/hover.go
index 7334d92..b8ab702 100644
--- a/internal/lsp/hover.go
+++ b/internal/lsp/hover.go
@@ -26,7 +26,7 @@
 	if err != nil {
 		return nil, err
 	}
-	ident, err := source.Identifier(ctx, snapshot, f, params.Position)
+	ident, err := source.Identifier(ctx, snapshot, f, params.Position, source.WidestCheckPackageHandle)
 	if err != nil {
 		return nil, nil
 	}
diff --git a/internal/lsp/implementation.go b/internal/lsp/implementation.go
index 9af0f70..010be7d 100644
--- a/internal/lsp/implementation.go
+++ b/internal/lsp/implementation.go
@@ -9,7 +9,9 @@
 
 	"golang.org/x/tools/internal/lsp/protocol"
 	"golang.org/x/tools/internal/lsp/source"
+	"golang.org/x/tools/internal/lsp/telemetry"
 	"golang.org/x/tools/internal/span"
+	"golang.org/x/tools/internal/telemetry/log"
 )
 
 func (s *Server) implementation(ctx context.Context, params *protocol.ImplementationParams) ([]protocol.Location, error) {
@@ -23,9 +25,45 @@
 	if err != nil {
 		return nil, err
 	}
-	ident, err := source.Identifier(ctx, snapshot, f, params.Position)
+
+	phs, err := snapshot.PackageHandles(ctx, snapshot.Handle(ctx, f))
 	if err != nil {
 		return nil, err
 	}
-	return ident.Implementation(ctx)
+
+	var (
+		allLocs []protocol.Location
+		seen    = make(map[protocol.Location]bool)
+	)
+	for _, ph := range phs {
+		ctx := telemetry.Package.With(ctx, ph.ID())
+
+		ident, err := source.Identifier(ctx, snapshot, f, params.Position, source.SpecificPackageHandle(ph.ID()))
+		if err != nil {
+			if err == source.ErrNoIdentFound {
+				return nil, err
+			}
+			log.Error(ctx, "failed to find Identifer", err)
+			continue
+		}
+
+		locs, err := ident.Implementation(ctx)
+		if err != nil {
+			if err == source.ErrNotAMethod {
+				return nil, err
+			}
+			log.Error(ctx, "failed to find Implemenation", err)
+			continue
+		}
+
+		for _, loc := range locs {
+			if seen[loc] {
+				continue
+			}
+			seen[loc] = true
+			allLocs = append(allLocs, loc)
+		}
+	}
+
+	return allLocs, nil
 }
diff --git a/internal/lsp/references.go b/internal/lsp/references.go
index 2dc37f2..ea6754b 100644
--- a/internal/lsp/references.go
+++ b/internal/lsp/references.go
@@ -26,7 +26,7 @@
 		return nil, err
 	}
 	// Find all references to the identifier at the position.
-	ident, err := source.Identifier(ctx, snapshot, f, params.Position)
+	ident, err := source.Identifier(ctx, snapshot, f, params.Position, source.WidestCheckPackageHandle)
 	if err != nil {
 		return nil, err
 	}
diff --git a/internal/lsp/rename.go b/internal/lsp/rename.go
index 1db1abd..18f9c79 100644
--- a/internal/lsp/rename.go
+++ b/internal/lsp/rename.go
@@ -23,7 +23,7 @@
 	if err != nil {
 		return nil, err
 	}
-	ident, err := source.Identifier(ctx, snapshot, f, params.Position)
+	ident, err := source.Identifier(ctx, snapshot, f, params.Position, source.WidestCheckPackageHandle)
 	if err != nil {
 		return nil, err
 	}
@@ -56,7 +56,7 @@
 	if err != nil {
 		return nil, err
 	}
-	ident, err := source.Identifier(ctx, snapshot, f, params.Position)
+	ident, err := source.Identifier(ctx, snapshot, f, params.Position, source.WidestCheckPackageHandle)
 	if err != nil {
 		return nil, nil // ignore errors
 	}
diff --git a/internal/lsp/source/identifier.go b/internal/lsp/source/identifier.go
index a942f5e..26d8183 100644
--- a/internal/lsp/source/identifier.go
+++ b/internal/lsp/source/identifier.go
@@ -58,11 +58,11 @@
 
 // Identifier returns identifier information for a position
 // in a file, accounting for a potentially incomplete selector.
-func Identifier(ctx context.Context, snapshot Snapshot, f File, pos protocol.Position) (*IdentifierInfo, error) {
+func Identifier(ctx context.Context, snapshot Snapshot, f File, pos protocol.Position, selectPackage PackagePolicy) (*IdentifierInfo, error) {
 	ctx, done := trace.StartSpan(ctx, "source.Identifier")
 	defer done()
 
-	pkg, pgh, err := getParsedFile(ctx, snapshot, f, WidestCheckPackageHandle)
+	pkg, pgh, err := getParsedFile(ctx, snapshot, f, selectPackage)
 	if err != nil {
 		return nil, fmt.Errorf("getting file for Identifier: %v", err)
 	}
@@ -81,6 +81,8 @@
 	return findIdentifier(snapshot, pkg, file, rng.Start)
 }
 
+var ErrNoIdentFound = errors.New("no identifier found")
+
 func findIdentifier(snapshot Snapshot, pkg Package, file *ast.File, pos token.Pos) (*IdentifierInfo, error) {
 	if result, err := identifier(snapshot, pkg, file, pos); err != nil || result != nil {
 		return result, err
@@ -90,7 +92,7 @@
 	// requesting a completion), use the path to the preceding node.
 	ident, err := identifier(snapshot, pkg, file, pos-1)
 	if ident == nil && err == nil {
-		err = errors.New("no identifier found")
+		err = ErrNoIdentFound
 	}
 	return ident, err
 }
diff --git a/internal/lsp/source/implementation.go b/internal/lsp/source/implementation.go
index ed8b163..e1578cd 100644
--- a/internal/lsp/source/implementation.go
+++ b/internal/lsp/source/implementation.go
@@ -19,6 +19,7 @@
 	"golang.org/x/tools/internal/lsp/protocol"
 	"golang.org/x/tools/internal/lsp/telemetry"
 	"golang.org/x/tools/internal/telemetry/log"
+	errors "golang.org/x/xerrors"
 )
 
 func (i *IdentifierInfo) Implementation(ctx context.Context) ([]protocol.Location, error) {
@@ -101,6 +102,8 @@
 	return locations, nil
 }
 
+var ErrNotAMethod = errors.New("this function is not a method")
+
 func (i *IdentifierInfo) implementations(ctx context.Context) (implementsResult, error) {
 	var T types.Type
 	var method *types.Func
@@ -112,7 +115,7 @@
 		}
 		recv := obj.Type().(*types.Signature).Recv()
 		if recv == nil {
-			return implementsResult{}, fmt.Errorf("this function is not a method")
+			return implementsResult{}, ErrNotAMethod
 		}
 		method = obj
 		T = recv.Type()
diff --git a/internal/lsp/source/source_test.go b/internal/lsp/source/source_test.go
index bdb3c66..f30e291 100644
--- a/internal/lsp/source/source_test.go
+++ b/internal/lsp/source/source_test.go
@@ -499,7 +499,7 @@
 	if err != nil {
 		t.Fatal(err)
 	}
-	ident, err := source.Identifier(ctx, r.view.Snapshot(), f, srcRng.Start)
+	ident, err := source.Identifier(ctx, r.view.Snapshot(), f, srcRng.Start, source.WidestCheckPackageHandle)
 	if err != nil {
 		t.Fatalf("failed for %v: %v", d.Src, err)
 	}
@@ -562,7 +562,7 @@
 	if err != nil {
 		t.Fatalf("failed for %v: %v", spn, err)
 	}
-	ident, err := source.Identifier(ctx, r.view.Snapshot(), f, loc.Range.Start)
+	ident, err := source.Identifier(ctx, r.view.Snapshot(), f, loc.Range.Start, source.WidestCheckPackageHandle)
 	if err != nil {
 		t.Fatalf("failed for %v: %v", spn, err)
 	}
@@ -649,7 +649,7 @@
 	if err != nil {
 		t.Fatal(err)
 	}
-	ident, err := source.Identifier(ctx, r.view.Snapshot(), f, srcRng.Start)
+	ident, err := source.Identifier(ctx, r.view.Snapshot(), f, srcRng.Start, source.WidestCheckPackageHandle)
 	if err != nil {
 		t.Fatalf("failed for %v: %v", src, err)
 	}
@@ -693,7 +693,7 @@
 	if err != nil {
 		t.Fatal(err)
 	}
-	ident, err := source.Identifier(r.ctx, r.view.Snapshot(), f, srcRng.Start)
+	ident, err := source.Identifier(r.ctx, r.view.Snapshot(), f, srcRng.Start, source.WidestCheckPackageHandle)
 	if err != nil {
 		t.Error(err)
 		return
@@ -782,7 +782,7 @@
 		t.Fatal(err)
 	}
 	// Find the identifier at the position.
-	ident, err := source.Identifier(ctx, r.view.Snapshot(), f, srcRng.Start)
+	ident, err := source.Identifier(ctx, r.view.Snapshot(), f, srcRng.Start, source.WidestCheckPackageHandle)
 	if err != nil {
 		if want.Text != "" { // expected an ident.
 			t.Errorf("prepare rename failed for %v: got error: %v", src, err)
diff --git a/internal/lsp/source/util.go b/internal/lsp/source/util.go
index 191e529..ada8444 100644
--- a/internal/lsp/source/util.go
+++ b/internal/lsp/source/util.go
@@ -67,7 +67,7 @@
 
 // getParsedFile is a convenience function that extracts the Package and ParseGoHandle for a File in a Snapshot.
 // selectPackage is typically Narrowest/WidestCheckPackageHandle below.
-func getParsedFile(ctx context.Context, snapshot Snapshot, f File, selectPackage func([]PackageHandle) (PackageHandle, error)) (Package, ParseGoHandle, error) {
+func getParsedFile(ctx context.Context, snapshot Snapshot, f File, selectPackage PackagePolicy) (Package, ParseGoHandle, error) {
 	fh := snapshot.Handle(ctx, f)
 	phs, err := snapshot.PackageHandles(ctx, fh)
 	if err != nil {
@@ -85,6 +85,8 @@
 	return pkg, pgh, err
 }
 
+type PackagePolicy func([]PackageHandle) (PackageHandle, error)
+
 // NarrowestCheckPackageHandle picks the "narrowest" package for a given file.
 //
 // By "narrowest" package, we mean the package with the fewest number of files
@@ -126,6 +128,20 @@
 	return result, nil
 }
 
+// SpecificPackageHandle creates a PackagePolicy to select a
+// particular PackageHandle when you alread know the one you want.
+func SpecificPackageHandle(desiredID string) PackagePolicy {
+	return func(handles []PackageHandle) (PackageHandle, error) {
+		for _, h := range handles {
+			if h.ID() == desiredID {
+				return h, nil
+			}
+		}
+
+		return nil, fmt.Errorf("no package handle with expected id %q", desiredID)
+	}
+}
+
 func IsGenerated(ctx context.Context, view View, uri span.URI) bool {
 	f, err := view.GetFile(ctx, uri)
 	if err != nil {