internal/lsp/source: add a unit test for searchForEnclosing
The logic to resolve the enclosing type for an identifier is somewhat
tricky. Add a unit test to exercise a few edge cases.
This would probably be easier to read and write using a hybrid approach
that extracts markers from the source.
This test uncovered a bug, that on the SelectorExpr branch we were
accidentally returning a nil *Named types.Type, rather than a nil
types.Type.
Change-Id: I43e096f51999b2a6e109c09d3805ad70a4780398
Reviewed-on: https://go-review.googlesource.com/c/tools/+/244841
Reviewed-by: Heschi Kreinick <heschi@google.com>
diff --git a/internal/lsp/source/identifier.go b/internal/lsp/source/identifier.go
index acb3bfd..d4f9591 100644
--- a/internal/lsp/source/identifier.go
+++ b/internal/lsp/source/identifier.go
@@ -135,7 +135,7 @@
qf: qf,
pkg: pkg,
ident: ident,
- enclosing: searchForEnclosing(pkg, path),
+ enclosing: searchForEnclosing(pkg.GetTypesInfo(), path),
}
var wasEmbeddedField bool
@@ -226,15 +226,15 @@
return result, nil
}
-func searchForEnclosing(pkg Package, path []ast.Node) types.Type {
+func searchForEnclosing(info *types.Info, path []ast.Node) types.Type {
for _, n := range path {
switch n := n.(type) {
case *ast.SelectorExpr:
- if sel, ok := pkg.GetTypesInfo().Selections[n]; ok {
+ if sel, ok := info.Selections[n]; ok {
recv := deref(sel.Recv())
// Keep track of the last exported type seen.
- var exported *types.Named
+ var exported types.Type
if named, ok := recv.(*types.Named); ok && named.Obj().Exported() {
exported = named
}
@@ -251,12 +251,12 @@
return exported
}
case *ast.CompositeLit:
- if t, ok := pkg.GetTypesInfo().Types[n]; ok {
+ if t, ok := info.Types[n]; ok {
return t.Type
}
case *ast.TypeSpec:
if _, ok := n.Type.(*ast.StructType); ok {
- if t, ok := pkg.GetTypesInfo().Defs[n.Name]; ok {
+ if t, ok := info.Defs[n.Name]; ok {
return t.Type()
}
}
diff --git a/internal/lsp/source/identifier_test.go b/internal/lsp/source/identifier_test.go
new file mode 100644
index 0000000..f07e401
--- /dev/null
+++ b/internal/lsp/source/identifier_test.go
@@ -0,0 +1,128 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package source
+
+import (
+ "bytes"
+ "go/ast"
+ "go/parser"
+ "go/token"
+ "go/types"
+ "testing"
+)
+
+func TestSearchForEnclosing(t *testing.T) {
+ tests := []struct {
+ desc string
+ // For convenience, consider the first occurence of the identifier "X" in
+ // src.
+ src string
+ // By convention, "" means no type found.
+ wantTypeName string
+ }{
+ {
+ desc: "self enclosing",
+ src: `package a; type X struct {}`,
+ wantTypeName: "X",
+ },
+ {
+ // TODO(rFindley): is this correct, or do we want to resolve I2 here?
+ desc: "embedded interface in interface",
+ src: `package a; var y = i1.X; type i1 interface {I2}; type I2 interface{X()}`,
+ wantTypeName: "",
+ },
+ {
+ desc: "embedded interface in struct",
+ src: `package a; var y = t.X; type t struct {I}; type I interface{X()}`,
+ wantTypeName: "I",
+ },
+ {
+ desc: "double embedding",
+ src: `package a; var y = t1.X; type t1 struct {t2}; type t2 struct {I}; type I interface{X()}`,
+ wantTypeName: "I",
+ },
+ {
+ desc: "struct field",
+ src: `package a; type T struct { X int }`,
+ wantTypeName: "T",
+ },
+ {
+ desc: "nested struct field",
+ src: `package a; type T struct { E struct { X int } }`,
+ wantTypeName: "T",
+ },
+ {
+ desc: "slice entry",
+ src: `package a; type T []int; var S = T{X}; var X int = 2`,
+ wantTypeName: "T",
+ },
+ {
+ desc: "struct pointer literal",
+ src: `package a; type T struct {i int}; var L = &T{X}; const X = 2`,
+ wantTypeName: "T",
+ },
+ }
+
+ for _, test := range tests {
+ test := test
+ t.Run(test.desc, func(t *testing.T) {
+ fset := token.NewFileSet()
+ file, err := parser.ParseFile(fset, "a.go", test.src, parser.AllErrors)
+ if err != nil {
+ t.Fatal(err)
+ }
+ column := 1 + bytes.IndexRune([]byte(test.src), 'X')
+ pos := posAt(1, column, fset, "a.go")
+ path := pathEnclosingObjNode(file, pos)
+ if path == nil {
+ t.Fatalf("no ident found at (1, %d)", column)
+ }
+ info := newInfo()
+ if _, err = (*types.Config)(nil).Check("p", fset, []*ast.File{file}, info); err != nil {
+ t.Fatal(err)
+ }
+ typ := searchForEnclosing(info, path)
+ if typ == nil {
+ if test.wantTypeName != "" {
+ t.Errorf("searchForEnclosing(...) = <nil>, want %q", test.wantTypeName)
+ }
+ return
+ }
+ if got := typ.(*types.Named).Obj().Name(); got != test.wantTypeName {
+ t.Errorf("searchForEnclosing(...) = %q, want %q", got, test.wantTypeName)
+ }
+ })
+ }
+}
+
+// posAt returns the token.Pos corresponding to the 1-based (line, column)
+// coordinates in the file fname of fset.
+func posAt(line, column int, fset *token.FileSet, fname string) token.Pos {
+ var tok *token.File
+ fset.Iterate(func(f *token.File) bool {
+ if f.Name() == fname {
+ tok = f
+ return false
+ }
+ return true
+ })
+ if tok == nil {
+ return token.NoPos
+ }
+ start := tok.LineStart(line)
+ return start + token.Pos(column-1)
+}
+
+// newInfo returns a types.Info with all maps populated.
+func newInfo() *types.Info {
+ return &types.Info{
+ Types: make(map[ast.Expr]types.TypeAndValue),
+ Defs: make(map[*ast.Ident]types.Object),
+ Uses: make(map[*ast.Ident]types.Object),
+ Implicits: make(map[ast.Node]types.Object),
+ Selections: make(map[*ast.SelectorExpr]*types.Selection),
+ Scopes: make(map[ast.Node]*types.Scope),
+ }
+}
