internal/lsp/source: improve completions at file scope
Add support for var/func/const/type/import keywords at the file scope.
I left out "package" because, currently, if you are completing
something that means you must already have a package declaration. The
main hurdle was that anything other than a decl keyword shows up as
an *ast.BadDecl at the file scope. To properly detect the prefix we
manually scan for the token containing the position.
I also made a couple small drive-by improvements:
- Also suggest "goto" and "type" keywords in functions.
- Allow completing directly before a comment, e.g. "foo<>//". I
needed this for a test that would have been annoying to write
otherwise.
Updates golang/go#34009.
Change-Id: I290e7bdda9e66a16f996cdc291985a54bf375231
Reviewed-on: https://go-review.googlesource.com/c/tools/+/217500
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
diff --git a/internal/lsp/source/completion.go b/internal/lsp/source/completion.go
index 8fc3930..bd25052 100644
--- a/internal/lsp/source/completion.go
+++ b/internal/lsp/source/completion.go
@@ -493,16 +493,24 @@
}
// Detect our surrounding identifier.
- if ident, ok := path[0].(*ast.Ident); ok {
+ switch leaf := path[0].(type) {
+ case *ast.Ident:
// In the normal case, our leaf AST node is the identifer being completed.
- c.setSurrounding(ident)
- } else {
+ c.setSurrounding(leaf)
+ case *ast.BadDecl:
+ // You don't get *ast.Idents at the file level, so look for bad
+ // decls and manually extract the surrounding token.
+ pos, _, lit := c.scanToken(ctx, src)
+ if pos.IsValid() {
+ c.setSurrounding(&ast.Ident{Name: lit, NamePos: pos})
+ }
+ default:
// Otherwise, manually extract the prefix if our containing token
// is a keyword. This improves completion after an "accidental
// keyword", e.g. completing to "variance" in "someFunc(var<>)".
- id := scanKeyword(c.pos, c.snapshot.View().Session().Cache().FileSet().File(c.pos), src)
- if id != nil {
- c.setSurrounding(id)
+ pos, tkn, lit := c.scanToken(ctx, src)
+ if pos.IsValid() && tkn.IsKeyword() {
+ c.setSurrounding(&ast.Ident{Name: lit, NamePos: pos})
}
}
@@ -512,7 +520,7 @@
// If we're inside a comment return comment completions
for _, comment := range file.Comments {
- if comment.Pos() <= rng.Start && rng.Start <= comment.End() {
+ if comment.Pos() < rng.Start && rng.Start <= comment.End() {
c.populateCommentCompletions(comment)
return c.items, c.getSurrounding(), nil
}
@@ -556,10 +564,6 @@
if err := c.lexical(); err != nil {
return nil, nil, err
}
- if err := c.keyword(); err != nil {
- return nil, nil, err
- }
-
// The function name hasn't been typed yet, but the parens are there:
// recv.‸(arg)
case *ast.TypeAssertExpr:
@@ -573,6 +577,10 @@
return nil, nil, err
}
+ // At the file scope, only keywords are allowed.
+ case *ast.BadDecl, *ast.File:
+ c.addKeywordCompletions()
+
default:
// fallback to lexical completions
if err := c.lexical(); err != nil {
@@ -583,20 +591,20 @@
return c.items, c.getSurrounding(), nil
}
-// scanKeyword scans file for the ident or keyword containing or abutting pos.
-func scanKeyword(pos token.Pos, file *token.File, data []byte) *ast.Ident {
+// scanToken scans pgh's contents for the token containing pos.
+func (c *completer) scanToken(ctx context.Context, contents []byte) (token.Pos, token.Token, string) {
+ tok := c.snapshot.View().Session().Cache().FileSet().File(c.pos)
+
var s scanner.Scanner
- s.Init(file, data, nil, 0)
+ s.Init(tok, contents, nil, 0)
for {
tknPos, tkn, lit := s.Scan()
- if tkn == token.EOF || tknPos >= pos {
- return nil
+ if tkn == token.EOF || tknPos >= c.pos {
+ return token.NoPos, token.ILLEGAL, ""
}
- if tkn.IsKeyword() {
- if tknPos <= pos && pos <= tknPos+token.Pos(len(lit)) {
- return &ast.Ident{NamePos: tknPos, Name: lit}
- }
+ if len(lit) > 0 && tknPos <= c.pos && c.pos <= tknPos+token.Pos(len(lit)) {
+ return tknPos, tkn, lit
}
}
}
@@ -1002,6 +1010,9 @@
}
}
+ // Add keyword completion items appropriate in the current context.
+ c.addKeywordCompletions()
+
return nil
}
diff --git a/internal/lsp/source/completion_keywords.go b/internal/lsp/source/completion_keywords.go
index dcb5c95..4cb7117 100644
--- a/internal/lsp/source/completion_keywords.go
+++ b/internal/lsp/source/completion_keywords.go
@@ -4,8 +4,6 @@
"go/ast"
"golang.org/x/tools/internal/lsp/protocol"
-
- errors "golang.org/x/xerrors"
)
const (
@@ -36,22 +34,48 @@
VAR = "var"
)
-// keyword looks at the current scope of an *ast.Ident and recommends keywords
-func (c *completer) keyword() error {
- keywordScore := float64(0.9)
- if _, ok := c.path[0].(*ast.Ident); !ok {
- // TODO(golang/go#34009): Support keyword completion in any context
- return errors.Errorf("keywords are currently only recommended for identifiers")
- }
- // Track which keywords we've already determined are in a valid scope
- // Use score to order keywords by how close we are to where they are useful
- valid := make(map[string]float64)
+// addKeywordCompletions offers keyword candidates appropriate at the position.
+func (c *completer) addKeywordCompletions() {
+ const keywordScore = 0.9
- // only suggest keywords at the begnning of a statement
+ seen := make(map[string]bool)
+
+ // addKeywords dedupes and adds completion items for the specified
+ // keywords with the specified score.
+ addKeywords := func(score float64, kws ...string) {
+ for _, kw := range kws {
+ if seen[kw] {
+ continue
+ }
+ seen[kw] = true
+
+ if c.matcher.Score(kw) > 0 {
+ c.items = append(c.items, CompletionItem{
+ Label: kw,
+ Kind: protocol.KeywordCompletion,
+ InsertText: kw,
+ Score: score,
+ })
+ }
+ }
+ }
+
+ // If we are at the file scope, only offer decl keywords. We don't
+ // get *ast.Idents at the file scope because non-keyword identifiers
+ // turn into *ast.BadDecl, not *ast.Ident.
+ if len(c.path) == 1 || isASTFile(c.path[1]) {
+ addKeywords(keywordScore, TYPE, CONST, VAR, FUNC, IMPORT)
+ return
+ } else if _, ok := c.path[0].(*ast.Ident); !ok {
+ // Otherwise only offer keywords if the client is completing an identifier.
+ return
+ }
+
+ // Only suggest keywords if we are beginning a statement.
switch c.path[1].(type) {
case *ast.BlockStmt, *ast.CommClause, *ast.CaseClause, *ast.ExprStmt:
default:
- return nil
+ return
}
// Filter out keywords depending on scope
@@ -62,7 +86,7 @@
case *ast.CaseClause:
// only recommend "fallthrough" and "break" within the bodies of a case clause
if c.pos > node.Colon {
- valid[BREAK] = keywordScore
+ addKeywords(keywordScore, BREAK)
// "fallthrough" is only valid in switch statements.
// A case clause is always nested within a block statement in a switch statement,
// that block statement is nested within either a TypeSwitchStmt or a SwitchStmt.
@@ -70,45 +94,23 @@
continue
}
if _, ok := path[i+2].(*ast.SwitchStmt); ok {
- valid[FALLTHROUGH] = keywordScore
+ addKeywords(keywordScore, FALLTHROUGH)
}
}
case *ast.CommClause:
if c.pos > node.Colon {
- valid[BREAK] = keywordScore
+ addKeywords(keywordScore, BREAK)
}
case *ast.TypeSwitchStmt, *ast.SelectStmt, *ast.SwitchStmt:
- valid[CASE] = keywordScore + lowScore
- valid[DEFAULT] = keywordScore + lowScore
+ addKeywords(keywordScore+lowScore, CASE, DEFAULT)
case *ast.ForStmt:
- valid[BREAK] = keywordScore
- valid[CONTINUE] = keywordScore
+ addKeywords(keywordScore, BREAK, CONTINUE)
// This is a bit weak, functions allow for many keywords
case *ast.FuncDecl:
if node.Body != nil && c.pos > node.Body.Lbrace {
- valid[DEFER] = keywordScore - lowScore
- valid[RETURN] = keywordScore - lowScore
- valid[FOR] = keywordScore - lowScore
- valid[GO] = keywordScore - lowScore
- valid[SWITCH] = keywordScore - lowScore
- valid[SELECT] = keywordScore - lowScore
- valid[IF] = keywordScore - lowScore
- valid[ELSE] = keywordScore - lowScore
- valid[VAR] = keywordScore - lowScore
- valid[CONST] = keywordScore - lowScore
+ addKeywords(keywordScore-lowScore, DEFER, RETURN, FOR, GO, SWITCH, SELECT, IF, ELSE, VAR, CONST, GOTO, TYPE)
}
}
}
- for ident, score := range valid {
- if c.matcher.Score(ident) > 0 {
- c.items = append(c.items, CompletionItem{
- Label: ident,
- Kind: protocol.KeywordCompletion,
- InsertText: ident,
- Score: score,
- })
- }
- }
- return nil
}
diff --git a/internal/lsp/source/util.go b/internal/lsp/source/util.go
index ffb166f..0a866bd 100644
--- a/internal/lsp/source/util.go
+++ b/internal/lsp/source/util.go
@@ -420,6 +420,11 @@
return ok
}
+func isASTFile(n ast.Node) bool {
+ _, ok := n.(*ast.File)
+ return ok
+}
+
// isSelector returns the enclosing *ast.SelectorExpr when pos is in the
// selector.
func enclosingSelector(path []ast.Node, pos token.Pos) *ast.SelectorExpr {
diff --git a/internal/lsp/testdata/lsp/primarymod/foo/foo.go b/internal/lsp/testdata/lsp/primarymod/foo/foo.go
index 277ac53..20ea183 100644
--- a/internal/lsp/testdata/lsp/primarymod/foo/foo.go
+++ b/internal/lsp/testdata/lsp/primarymod/foo/foo.go
@@ -27,4 +27,4 @@
}
}
-type IntFoo int //@item(IntFoo, "IntFoo", "int", "type"),complete("", Foo, IntFoo, StructFoo)
+type IntFoo int //@item(IntFoo, "IntFoo", "int", "type")
diff --git a/internal/lsp/testdata/lsp/primarymod/keywords/keywords.go b/internal/lsp/testdata/lsp/primarymod/keywords/keywords.go
index 5fda68d..7e7fd5b 100644
--- a/internal/lsp/testdata/lsp/primarymod/keywords/keywords.go
+++ b/internal/lsp/testdata/lsp/primarymod/keywords/keywords.go
@@ -1,5 +1,7 @@
package keywords
+//@rank("", type),rank("", func),rank("", var),rank("", const),rank("", import)
+
func _() {
var test int
var tChan chan int
@@ -42,7 +44,7 @@
f //@complete(" //", for)
d //@complete(" //", defer)
- g //@complete(" //", go)
+ g //@rank(" //", go),rank(" //", goto)
r //@complete(" //", return)
i //@complete(" //", if)
e //@complete(" //", else)
@@ -72,3 +74,4 @@
/* return */ //@item(return, "return", "", "keyword")
/* var */ //@item(var, "var", "", "keyword")
/* const */ //@item(const, "const", "", "keyword")
+/* goto */ //@item(goto, "goto", "", "keyword")
diff --git a/internal/lsp/testdata/lsp/summary.txt.golden b/internal/lsp/testdata/lsp/summary.txt.golden
index 4845142..b36331b 100644
--- a/internal/lsp/testdata/lsp/summary.txt.golden
+++ b/internal/lsp/testdata/lsp/summary.txt.golden
@@ -1,11 +1,11 @@
-- summary --
CodeLensCount = 0
-CompletionsCount = 228
+CompletionsCount = 226
CompletionSnippetCount = 67
UnimportedCompletionsCount = 11
DeepCompletionsCount = 5
FuzzyCompletionsCount = 8
-RankedCompletionsCount = 102
+RankedCompletionsCount = 109
CaseSensitiveCompletionsCount = 4
DiagnosticsCount = 38
FoldingRangesCount = 2
