internal/lsp: set severity levels for compiler errors and vet checks

This change adds severity levels to source.Diagnostics, allowing us to
pass this information along to the LSP. This allows compiler errors to
show up in red, while vet results show up in green.

Change-Id: I2bc0b27ed6629f987c05affe00fdbe4b9bfb3b3e
Reviewed-on: https://go-review.googlesource.com/c/164299
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>

internal/lsp/diagnostics.go

@@ -51,15 +51,22 @@ func toProtocolDiagnostics(ctx context.Context, v source.View, diagnostics []sou
 	reports := []protocol.Diagnostic{}
 	for _, diag := range diagnostics {
 		tok := v.FileSet().File(diag.Start)
-		source := diag.Source
+		src := diag.Source
-		if source == "" {
+		if src == "" {
-			source = "LSP"
+			src = "LSP"
+		}
+		var severity protocol.DiagnosticSeverity
+		switch diag.Severity {
+		case source.SeverityError:
+			severity = protocol.SeverityError
+		case source.SeverityWarning:
+			severity = protocol.SeverityWarning
 		}
 		reports = append(reports, protocol.Diagnostic{
 			Message:  diag.Message,
 			Range:    toProtocolRange(tok, diag.Range),
-			Severity: protocol.SeverityError, // all diagnostics have error severity for now
+			Severity: severity,
-			Source:   source,
+			Source:   src,
 		})
 	}
 	return reports

internal/lsp/lsp_test.go

@@ -182,9 +182,13 @@ func (d diagnostics) collect(fset *token.FileSet, rng packagestest.Range, msgSou
 	if msg == "" {
 		return
 	}
+	severity := protocol.SeverityError
+	if strings.Contains(f.Name(), "analyzer") {
+		severity = protocol.SeverityWarning
+	}
 	want := protocol.Diagnostic{
 		Range:    toProtocolRange(f, source.Range(rng)),
-		Severity: protocol.SeverityError,
+		Severity: severity,
 		Source:   msgSource,
 		Message:  msg,
 	}

internal/lsp/source/diagnostics.go

@@ -41,10 +41,18 @@ import (
 
 type Diagnostic struct {
 	Range
-	Message string
+	Message  string
-	Source  string
+	Source   string
+	Severity DiagnosticSeverity
 }
 
+type DiagnosticSeverity int
+
+const (
+	SeverityWarning DiagnosticSeverity = iota
+	SeverityError
+)
+
 func Diagnostics(ctx context.Context, v View, uri URI) (map[string][]Diagnostic, error) {
 	f, err := v.GetFile(ctx, uri)
 	if err != nil {
@@ -98,7 +106,8 @@ func Diagnostics(ctx context.Context, v View, uri URI) (map[string][]Diagnostic,
 				Start: startPos,
 				End:   endPos,
 			},
-			Message: diag.Msg,
+			Message:  diag.Msg,
+			Severity: SeverityError,
 		}
 		if _, ok := reports[pos.Filename]; ok {
 			reports[pos.Filename] = append(reports[pos.Filename], diagnostic)
@@ -116,9 +125,10 @@ func Diagnostics(ctx context.Context, v View, uri URI) (map[string][]Diagnostic,
 		}
 
 		reports[pos.Filename] = append(reports[pos.Filename], Diagnostic{
-			Source:  category,
+			Source:   category,
-			Range:   Range{Start: diag.Pos, End: diag.Pos},
+			Range:    Range{Start: diag.Pos, End: diag.Pos},
-			Message: fmt.Sprintf(diag.Message),
+			Message:  fmt.Sprintf(diag.Message),
+			Severity: SeverityWarning,
 		})
 	})