From 62138107dfcf98a2a23c0fb5a91983423e39973a Mon Sep 17 00:00:00 2001
From: Rebecca Stambler <rstambler@golang.org>
Date: Thu, 20 Dec 2018 17:31:55 -0500
Subject: [PATCH] internal/lsp: fix diagnostics range computation

Diagnostics were failing because of
https://go-review.googlesource.com/c/tools/+/154742, where I was using
the wrong *token.File for the position calculations. This should fix the
problem.

Change-Id: Ic44e7799da56010b5014d56029fb4e0a8a6bb0e8
Reviewed-on: https://go-review.googlesource.com/c/155479
Reviewed-by: Ian Cottrell <iancottrell@google.com>
---
 internal/lsp/diagnostics.go        | 16 ++++------------
 internal/lsp/lsp_test.go           |  2 +-
 internal/lsp/source/definition.go  |  4 ++--
 internal/lsp/source/diagnostics.go | 12 ++++++++++--
 4 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/internal/lsp/diagnostics.go b/internal/lsp/diagnostics.go
index 02102867..49743dc0 100644
--- a/internal/lsp/diagnostics.go
+++ b/internal/lsp/diagnostics.go
@@ -23,10 +23,9 @@ func (s *server) cacheAndDiagnose(ctx context.Context, uri protocol.DocumentURI,
 			return // handle error?
 		}
 		for filename, diagnostics := range reports {
-			uri := source.ToURI(filename)
 			s.client.PublishDiagnostics(ctx, &protocol.PublishDiagnosticsParams{
-				URI:         protocol.DocumentURI(uri),
-				Diagnostics: toProtocolDiagnostics(ctx, s.view, uri, diagnostics),
+				URI:         protocol.DocumentURI(source.ToURI(filename)),
+				Diagnostics: toProtocolDiagnostics(ctx, s.view, diagnostics),
 			})
 		}
 	}()
@@ -45,17 +44,10 @@ func (s *server) setContent(ctx context.Context, uri source.URI, content []byte)
 	return nil
 }
 
-func toProtocolDiagnostics(ctx context.Context, v source.View, uri source.URI, diagnostics []source.Diagnostic) []protocol.Diagnostic {
+func toProtocolDiagnostics(ctx context.Context, v source.View, diagnostics []source.Diagnostic) []protocol.Diagnostic {
 	reports := []protocol.Diagnostic{}
 	for _, diag := range diagnostics {
-		f, err := v.GetFile(ctx, uri)
-		if err != nil {
-			continue // handle error?
-		}
-		tok, err := f.GetToken()
-		if err != nil {
-			continue // handle error?
-		}
+		tok := v.FileSet().File(diag.Start)
 		reports = append(reports, protocol.Diagnostic{
 			Message:  diag.Message,
 			Range:    toProtocolRange(tok, diag.Range),
diff --git a/internal/lsp/lsp_test.go b/internal/lsp/lsp_test.go
index 73c1d4fb..264e4e01 100644
--- a/internal/lsp/lsp_test.go
+++ b/internal/lsp/lsp_test.go
@@ -157,7 +157,7 @@ func (d diagnostics) test(t *testing.T, exported *packagestest.Exported, v sourc
 		if err != nil {
 			t.Fatal(err)
 		}
-		got := toProtocolDiagnostics(ctx, v, source.ToURI(filename), sourceDiagnostics[filename])
+		got := toProtocolDiagnostics(ctx, v, sourceDiagnostics[filename])
 		sorted(got)
 		if diff := diffDiagnostics(filename, want, got); diff != "" {
 			t.Error(diff)
diff --git a/internal/lsp/source/definition.go b/internal/lsp/source/definition.go
index 79eb93ff..778566cb 100644
--- a/internal/lsp/source/definition.go
+++ b/internal/lsp/source/definition.go
@@ -139,8 +139,8 @@ func checkIdentifier(f *ast.File, pos token.Pos) (ident, error) {
 
 func objToRange(ctx context.Context, v View, fset *token.FileSet, obj types.Object) Range {
 	p := obj.Pos()
-	f := fset.File(p)
-	pos := f.Position(p)
+	tok := fset.File(p)
+	pos := tok.Position(p)
 	if pos.Column == 1 {
 		// We do not have full position information because exportdata does not
 		// store the column. For now, we attempt to read the original source
diff --git a/internal/lsp/source/diagnostics.go b/internal/lsp/source/diagnostics.go
index 1b84d3c5..7c393aec 100644
--- a/internal/lsp/source/diagnostics.go
+++ b/internal/lsp/source/diagnostics.go
@@ -70,10 +70,18 @@ func Diagnostics(ctx context.Context, v View, uri URI) (map[string][]Diagnostic,
 		if err != nil || diag.Kind != packages.TypeError {
 			end = 0
 		}
+		startPos := fromTokenPosition(diagTok, pos.Line, pos.Column)
+		if !startPos.IsValid() {
+			continue
+		}
+		endPos := fromTokenPosition(diagTok, pos.Line, pos.Column+end)
+		if !endPos.IsValid() {
+			continue
+		}
 		diagnostic := Diagnostic{
 			Range: Range{
-				Start: fromTokenPosition(diagTok, pos.Line, pos.Column),
-				End:   fromTokenPosition(diagTok, pos.Line, pos.Column+end),
+				Start: startPos,
+				End:   endPos,
 			},
 			Message: diag.Msg,
 		}