internal/lsp/source: rename uses of embedded fields

When renaming a type name, also rename indirect uses of the name as an
embedded field. This is conservatively isolated to just renames for now;
it's not clear to me that users would also want to see uses of embedded
fields as references.

Fixes golang/go#43616

Change-Id: I41913d037fedb8c27a448cd922eeaf11a02d01f1
Reviewed-on: https://go-review.googlesource.com/c/tools/+/282932
Run-TryBot: Robert Findley <rfindley@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
Trust: Robert Findley <rfindley@google.com>

Author: findleyr

internal/lsp/source/references.go

@@ -42,7 +42,7 @@ func References(ctx context.Context, s Snapshot, f FileHandle, pp protocol.Posit
 		return nil, err
 	}
 
-	refs, err := references(ctx, s, qualifiedObjs, includeDeclaration, true)
+	refs, err := references(ctx, s, qualifiedObjs, includeDeclaration, true, false)
 	if err != nil {
 		return nil, err
 	}
@@ -62,10 +62,10 @@ func References(ctx context.Context, s Snapshot, f FileHandle, pp protocol.Posit
 }
 
 // references is a helper function to avoid recomputing qualifiedObjsAtProtocolPos.
-func references(ctx context.Context, snapshot Snapshot, qos []qualifiedObject, includeDeclaration, includeInterfaceRefs bool) ([]*ReferenceInfo, error) {
+func references(ctx context.Context, snapshot Snapshot, qos []qualifiedObject, includeDeclaration, includeInterfaceRefs, includeEmbeddedRefs bool) ([]*ReferenceInfo, error) {
 	var (
 		references []*ReferenceInfo
-		seen       = make(map[token.Position]bool)
+		seen       = make(map[token.Pos]bool)
 	)
 
 	filename := snapshot.FileSet().Position(qos[0].obj.Pos()).Filename
@@ -105,13 +105,25 @@ func references(ctx context.Context, snapshot Snapshot, qos []qualifiedObject, i
 		for _, pkg := range searchPkgs {
 			for ident, obj := range pkg.GetTypesInfo().Uses {
 				if obj != qo.obj {
-					continue
+					// If ident is not a use of qo.obj, skip it, with one exception: uses
+					// of an embedded field can be considered references of the embedded
+					// type name.
+					if !includeEmbeddedRefs {
+						continue
+					}
+					v, ok := obj.(*types.Var)
+					if !ok || !v.Embedded() {
+						continue
+					}
+					named, ok := v.Type().(*types.Named)
+					if !ok || named.Obj() != qo.obj {
+						continue
+					}
 				}
-				pos := snapshot.FileSet().Position(ident.Pos())
-				if seen[pos] {
+				if seen[ident.Pos()] {
 					continue
 				}
-				seen[pos] = true
+				seen[ident.Pos()] = true
 				rng, err := posToMappedRange(snapshot, pkg, ident.Pos(), ident.End())
 				if err != nil {
 					return nil, err
@@ -150,7 +162,7 @@ func references(ctx context.Context, snapshot Snapshot, qos []qualifiedObject, i
 	return references, nil
 }
 
-// interfaceReferences returns the references to the interfaces implemeneted by
+// interfaceReferences returns the references to the interfaces implemented by
 // the type or method at the given position.
 func interfaceReferences(ctx context.Context, s Snapshot, f FileHandle, pp protocol.Position) ([]*ReferenceInfo, error) {
 	implementations, err := implementations(ctx, s, f, pp)
@@ -163,7 +175,7 @@ func interfaceReferences(ctx context.Context, s Snapshot, f FileHandle, pp proto
 
 	var refs []*ReferenceInfo
 	for _, impl := range implementations {
-		implRefs, err := references(ctx, s, []qualifiedObject{impl}, false, false)
+		implRefs, err := references(ctx, s, []qualifiedObject{impl}, false, false, false)
 		if err != nil {
 			return nil, err
 		}

internal/lsp/source/rename.go

@@ -91,7 +91,7 @@ func Rename(ctx context.Context, s Snapshot, f FileHandle, pp protocol.Position,
 	if pkg == nil || pkg.IsIllTyped() {
 		return nil, errors.Errorf("package for %s is ill typed", f.URI())
 	}
-	refs, err := references(ctx, s, qos, true, false)
+	refs, err := references(ctx, s, qos, true, false, true)
 	if err != nil {
 		return nil, err
 	}

internal/lsp/testdata/rename/issue43616/issue43616.go.golden

@@ -0,0 +1,9 @@
+-- bar-rename --
+package issue43616
+
+type bar int //@rename("foo","bar")
+
+var x struct{ bar }
+
+var _ = x.bar
+

internal/lsp/testdata/rename/issue43616/issue43616.go.in

@@ -0,0 +1,7 @@
+package issue43616
+
+type foo int //@rename("foo","bar")
+
+var x struct{ foo }
+
+var _ = x.foo

internal/lsp/testdata/summary.txt.golden

@@ -19,7 +19,7 @@ DefinitionsCount = 64
 TypeDefinitionsCount = 2
 HighlightsCount = 69
 ReferencesCount = 25
-RenamesCount = 30
+RenamesCount = 31
 PrepareRenamesCount = 7
 SymbolsCount = 5
 WorkspaceSymbolsCount = 20