internal/lsp: add additional tests for completion

New tests include cases for anonymous structs, composite literals,
ranking of results in binary expressions, and import cycles.

Change-Id: Ic02e84e09101bb9873fc1705bba2594d655bb45b
Reviewed-on: https://go-review.googlesource.com/c/153443
Reviewed-by: Ian Cottrell <iancottrell@google.com>

internal/lsp/completion.go

@@ -14,28 +14,28 @@ import (
 	"golang.org/x/tools/internal/lsp/source"
 )
 
-func toProtocolCompletionItems(items []source.CompletionItem, prefix string, pos protocol.Position, snippetsSupported, signatureHelpEnabled bool) []protocol.CompletionItem {
-	var results []protocol.CompletionItem
-	sort.Slice(items, func(i, j int) bool {
-		return items[i].Score > items[j].Score
-	})
+func toProtocolCompletionItems(candidates []source.CompletionItem, prefix string, pos protocol.Position, snippetsSupported, signatureHelpEnabled bool) []protocol.CompletionItem {
 	insertTextFormat := protocol.PlainTextFormat
 	if snippetsSupported {
 		insertTextFormat = protocol.SnippetTextFormat
 	}
-	for i, item := range items {
+	sort.SliceStable(candidates, func(i, j int) bool {
+		return candidates[i].Score > candidates[j].Score
+	})
+	var items []protocol.CompletionItem
+	for i, candidate := range candidates {
 		// Matching against the label.
-		if !strings.HasPrefix(item.Label, prefix) {
+		if !strings.HasPrefix(candidate.Label, prefix) {
 			continue
 		}
-		insertText, triggerSignatureHelp := labelToProtocolSnippets(item.Label, item.Kind, insertTextFormat, signatureHelpEnabled)
+		insertText, triggerSignatureHelp := labelToProtocolSnippets(candidate.Label, candidate.Kind, insertTextFormat, signatureHelpEnabled)
 		if strings.HasPrefix(insertText, prefix) {
 			insertText = insertText[len(prefix):]
 		}
-		i := protocol.CompletionItem{
-			Label:            item.Label,
-			Detail:           item.Detail,
-			Kind:             float64(toProtocolCompletionItemKind(item.Kind)),
+		item := protocol.CompletionItem{
+			Label:            candidate.Label,
+			Detail:           candidate.Detail,
+			Kind:             float64(toProtocolCompletionItemKind(candidate.Kind)),
 			InsertTextFormat: insertTextFormat,
 			TextEdit: &protocol.TextEdit{
 				NewText: insertText,
@@ -53,13 +53,13 @@ func toProtocolCompletionItems(items []source.CompletionItem, prefix string, pos
 		}
 		// If we are completing a function, we should trigger signature help if possible.
 		if triggerSignatureHelp && signatureHelpEnabled {
-			i.Command = &protocol.Command{
+			item.Command = &protocol.Command{
 				Command: "editor.action.triggerParameterHints",
 			}
 		}
-		results = append(results, i)
+		items = append(items, item)
 	}
-	return results
+	return items
 }
 
 func toProtocolCompletionItemKind(kind source.CompletionItemKind) protocol.CompletionItemKind {

internal/lsp/lsp_test.go

@@ -35,8 +35,8 @@ func testLSP(t *testing.T, exporter packagestest.Exporter) {
 
 	// 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 = 44
-	const expectedDiagnosticsCount = 14
+	const expectedCompletionsCount = 60
+	const expectedDiagnosticsCount = 15
 	const expectedFormatCount = 3
 	const expectedDefinitionsCount = 16
 	const expectedTypeDefinitionsCount = 2

internal/lsp/testdata/anon/anon.go.in

@@ -0,0 +1,23 @@
+package anon
+
+func _() {
+	for _, _ := range []struct {
+		i, j int //@item(anonI, "i", "int", "field"),item(anonJ, "j", "int", "field")
+	}{
+		{
+			i: 1,
+			//@complete("", anonJ)
+		},
+		{
+			//@complete("", anonI, anonJ)
+		},
+	} {
+		continue
+	}
+
+	s := struct{ f int }{  } //@item(anonF, "f", "int", "field"),item(structS, "s", "struct{...}", "var"),complete("  }", anonF)
+
+	_ = map[struct{ x int }]int{ //@item(anonX, "x", "int", "field")
+		struct{ x int }{  }: 1, //@complete("  }", anonX, structS)
+	}
+}

internal/lsp/testdata/assign_rank/assign_rank.go.in

@@ -1,19 +0,0 @@
-package assign_rank
-
-var (
-  apple int = 3         //@item(apple, "apple", "int", "var")
-  pear string = "hello" //@item(pear, "pear", "string", "var")
-)
-
-func _() {
-	orange := 1      //@item(orange, "orange", "int", "var")
-	grape := "hello" //@item(grape, "grape", "string", "var")
- 	orange, grape = 2, "hello"  //@complete(" \"", grape, pear, orange, apple)
-}
-
-func _() {
-  var pineapple int //@item(pineapple, "pineapple", "int", "var")
-  pineapple =       //@complete(" /", pineapple, apple, pear)
-
-  y :=              //@complete(" /", pineapple, apple, pear)
-}

internal/lsp/testdata/builtins/builtins.go

@@ -0,0 +1,6 @@
+package builtins
+
+func _() {
+	// TODO(rstambler): Add testing for completion of builtin symbols.
+	//@complete("")
+}

internal/lsp/testdata/complit/complit.go.in

@@ -0,0 +1,26 @@
+package complit
+
+type position struct { //@item(structPosition, "position", "struct{...}", "struct")
+	X, Y int //@item(fieldX, "X", "int", "field"),item(fieldY, "Y", "int", "field")
+}
+
+func _() {
+	_ := position{
+		//@complete("", fieldX, fieldY, structPosition)
+	}
+	_ := position{
+		X: 1,
+		//@complete("", fieldY)
+	}
+	_ := position{
+		//@complete("", fieldX)
+		Y: 1,
+	}
+}
+
+func _() {
+	_ := position{
+		X: 1, //@complete("X", fieldX),complete(" 1", structPosition)
+		Y: ,  //@complete(":", fieldY),complete(" ,", structPosition)
+	}
+}

internal/lsp/testdata/errors/errors.go

@@ -0,0 +1,5 @@
+package errors
+
+func _() {
+	bob.Bob() //@complete(".")
+}

internal/lsp/testdata/rank/assign_rank.go.in

@@ -0,0 +1,19 @@
+package rank
+
+var (
+	apple int = 3         //@item(apple, "apple", "int", "var")
+	pear string = "hello" //@item(pear, "pear", "string", "var")
+)
+
+func _() {
+	orange := 1      //@item(orange, "orange", "int", "var")
+	grape := "hello" //@item(grape, "grape", "string", "var")
+	orange, grape = 2, "hello"  //@complete(" \"", grape, pear, orange, apple)
+}
+
+func _() {
+	var pineapple int //@item(pineapple, "pineapple", "int", "var")
+	pineapple =     //@complete(" /", pineapple, apple, pear)
+
+	y :=  //@complete(" /", pineapple, apple, pear)
+}

internal/lsp/testdata/rank/binexpr_rank.go.in

@@ -0,0 +1,8 @@
+package rank
+
+func _() {
+  _ = 5 +  ; //@complete(" ;", apple, pear)
+  y :=  + 5; //@complete(" +", apple, pear)
+
+  if 6 ==  {} //@complete(" {", apple, pear)
+}

internal/lsp/testdata/self/self.go.in

@@ -0,0 +1,13 @@
+// +build go1.11
+
+package self
+
+import (
+	"golang.org/x/tools/internal/lsp/self" //@diag("\"", "could not import golang.org/x/tools/internal/lsp/self (import cycle: [golang.org/x/tools/internal/lsp/self])")
+)
+
+func Hello() {}
+
+func _() {
+	self.Hello()
+}