internal/lsp: fix completion for nested *ast.BadStmt
Now when trying to fix *ast.BadStmt, we parse the manually extracted
expression using parser.ParseFile instead of parser.ParseExpr.
ParseFile will yield *ast.BadStmt nodes for any bad statements nested
in our first bad statement, allowing us to fix them recursively.
To turn our expression into a "valid" file we can pass to
parser.ParseFile, I wrapped it thusly:
package fake
func _() {
<our expression>
}
Change-Id: I0d4fd4ebce6450021da8e03caa11d0ae5152ea8d
Reviewed-on: https://go-review.googlesource.com/c/tools/+/194342
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
diff --git a/internal/lsp/cache/parse.go b/internal/lsp/cache/parse.go
index 5413062..643b1d8 100644
--- a/internal/lsp/cache/parse.go
+++ b/internal/lsp/cache/parse.go
@@ -171,12 +171,12 @@
// fix inspects the AST and potentially modifies any *ast.BadStmts so that it can be
// type-checked more effectively.
-func fix(ctx context.Context, file *ast.File, tok *token.File, src []byte) error {
+func fix(ctx context.Context, n ast.Node, tok *token.File, src []byte) error {
var (
ancestors []ast.Node
err error
)
- ast.Inspect(file, func(n ast.Node) bool {
+ ast.Inspect(n, func(n ast.Node) bool {
if n == nil {
if len(ancestors) > 0 {
ancestors = ancestors[:len(ancestors)-1]
@@ -190,7 +190,10 @@
parent = ancestors[len(ancestors)-1]
}
err = parseDeferOrGoStmt(n, parent, tok, src) // don't shadow err
- if err != nil {
+ if err == nil {
+ // Recursively fix any BadStmts in our fixed node.
+ err = fix(ctx, parent, tok, src)
+ } else {
err = errors.Errorf("unable to parse defer or go from *ast.BadStmt: %v", err)
}
return false
@@ -329,17 +332,40 @@
exprBytes = append(exprBytes, '_')
}
- exprStr := string(exprBytes)
- expr, err := parser.ParseExpr(exprStr)
- if expr == nil {
- return errors.Errorf("no expr in %s: %v", exprStr, err)
+ // Wrap our expression to make it a valid Go file we can pass to ParseFile.
+ fileSrc := bytes.Join([][]byte{
+ []byte("package fake;func _(){"),
+ exprBytes,
+ []byte("}"),
+ }, nil)
+
+ // Use ParseFile instead of ParseExpr because ParseFile has
+ // best-effort behavior, whereas ParseExpr fails hard on any error.
+ fakeFile, err := parser.ParseFile(token.NewFileSet(), "", fileSrc, 0)
+ if fakeFile == nil {
+ return errors.Errorf("error reading fake file source: %v", err)
}
+ // Extract our expression node from inside the fake file.
+ if len(fakeFile.Decls) == 0 {
+ return errors.Errorf("error parsing fake file: %v", err)
+ }
+ fakeDecl, _ := fakeFile.Decls[0].(*ast.FuncDecl)
+ if fakeDecl == nil || len(fakeDecl.Body.List) == 0 {
+ return errors.Errorf("no statement in %s: %v", exprBytes, err)
+ }
+ exprStmt, ok := fakeDecl.Body.List[0].(*ast.ExprStmt)
+ if !ok {
+ return errors.Errorf("no expr in %s: %v", exprBytes, err)
+ }
+ expr := exprStmt.X
+
// parser.ParseExpr returns undefined positions.
// Adjust them for the current file.
- offsetPositions(expr, from-1)
+ offsetPositions(expr, from-1-(expr.Pos()-1))
- // Package the expression into a fake *ast.CallExpr and re-insert into the function.
+ // Package the expression into a fake *ast.CallExpr and re-insert
+ // into the function.
call := &ast.CallExpr{
Fun: expr,
Lparen: to,
diff --git a/internal/lsp/testdata/badstmt/badstmt_4.go.in b/internal/lsp/testdata/badstmt/badstmt_4.go.in
new file mode 100644
index 0000000..8767306
--- /dev/null
+++ b/internal/lsp/testdata/badstmt/badstmt_4.go.in
@@ -0,0 +1,11 @@
+package badstmt
+
+import (
+ "golang.org/x/tools/internal/lsp/foo"
+)
+
+func _() {
+ go func() {
+ defer foo. //@complete(" //", Foo, IntFoo, StructFoo)
+ }
+}
diff --git a/internal/lsp/tests/tests.go b/internal/lsp/tests/tests.go
index 92a7260..67f155a 100644
--- a/internal/lsp/tests/tests.go
+++ b/internal/lsp/tests/tests.go
@@ -29,7 +29,7 @@
// We hardcode the expected number of test cases to ensure that all tests
// are being executed. If a test is added, this number must be changed.
const (
- ExpectedCompletionsCount = 159
+ ExpectedCompletionsCount = 160
ExpectedCompletionSnippetCount = 16
ExpectedDiagnosticsCount = 21
ExpectedFormatCount = 6
