Repair monikers for fields and methods (#63)

internal/index/helper.go

@@ -14,6 +14,46 @@ import (
 	"golang.org/x/tools/go/packages"
 )
 
+// monikerIdentifier constructs a moniker identifier from an ident. We can't just use the
+// ident name itself as this causes non-unique moniker generations (such as a String function
+// and a struct that conforms to the Stringer interface).
+func monikerIdentifier(f *ast.File, pkgPath string, ident *ast.Ident, obj types.Object) string {
+	// See if the ident is a signature with a receiver. If so, then we want to trim
+	// any leading * indicating a pointer receiver, then try to trim the package path.
+	// This constructs something like `{pkg}:{struct}.{method}`.
+	if signature, ok := obj.Type().(*types.Signature); ok {
+		if recv := signature.Recv(); recv != nil {
+			return fmt.Sprintf(
+				"%s:%s.%s",
+				pkgPath,
+				safeTrim(safeTrim(recv.Type().String(), "*"), pkgPath+"."),
+				ident.String(),
+			)
+		}
+	}
+
+	// See if the ident is a field of an outer type. If so, then we need to find the
+	// type spec that encloses it. This construct something like `{pkg}:{struct}.{field}`.
+	if v, ok := obj.(*types.Var); ok && v.IsField() {
+		if path, exact := astutil.PathEnclosingInterval(f, ident.Pos(), ident.Pos()); exact {
+			for _, node := range path {
+				if spec, ok := node.(*ast.TypeSpec); ok {
+					return fmt.Sprintf("%s:%s.%s", pkgPath, spec.Name.String(), ident.String())
+				}
+			}
+		}
+	}
+
+	return fmt.Sprintf("%s:%s", pkgPath, ident.String())
+}
+
+func safeTrim(s, prefix string) string {
+	if strings.HasPrefix(s, prefix) {
+		return s[len(prefix):]
+	}
+	return s
+}
+
 // lspRange transforms go/token.Position (1-based) to LSP start and end ranges (0-based)
 // which takes in consideration of identifier's name length. If the token is a quoted
 // package name, we'll create a range that covers only the string contents, not the quotes.

internal/index/indexer.go

@@ -315,7 +315,7 @@ func (i *indexer) indexPkgUses(pkgs []*packages.Package, p *packages.Package, pr
 		}
 		i.usesIndexed[fpos.Filename] = true
 
-		if err := i.indexUses(pkgs, p, fi, fpos.Filename); err != nil {
+		if err := i.indexUses(pkgs, p, f, fi, fpos.Filename); err != nil {
 			return fmt.Errorf("error indexing uses of %q: %v", p.PkgPath, err)
 		}
 	}
@@ -461,7 +461,7 @@ func (i *indexer) indexDefs(pkgs []*packages.Package, p *packages.Package, f *as
 		}
 
 		if ident.IsExported() {
-			err := i.emitExportMoniker(refResult.resultSetID, fmt.Sprintf("%s:%s", p.PkgPath, ident.String()))
+			err := i.emitExportMoniker(refResult.resultSetID, monikerIdentifier(f, p.PkgPath, ident, obj))
 			if err != nil {
 				return fmt.Errorf(`emit moniker": %v`, err)
 			}
@@ -484,7 +484,7 @@ func (i *indexer) indexDefs(pkgs []*packages.Package, p *packages.Package, f *as
 	return nil
 }
 
-func (i *indexer) indexUses(pkgs []*packages.Package, p *packages.Package, fi *fileInfo, filename string) error {
+func (i *indexer) indexUses(pkgs []*packages.Package, p *packages.Package, f *ast.File, fi *fileInfo, filename string) error {
 	var rangeIDs []string
 	for ident, obj := range p.TypesInfo.Uses {
 		// Only emit if the object belongs to current file
@@ -550,7 +550,7 @@ func (i *indexer) indexUses(pkgs []*packages.Package, p *packages.Package, fi *f
 
 			// If we don't have a definition in this package, emit an import moniker
 			// so that we can correlate it with another dump's LSIF data.
-			err = i.emitImportMoniker(rangeID, fmt.Sprintf("%s:%s", pkg.Path(), obj.Id()))
+			err = i.emitImportMoniker(rangeID, monikerIdentifier(f, pkg.Path(), ident, obj))
 			if err != nil {
 				return fmt.Errorf(`emit moniker": %v`, err)
 			}