gopls/internal/lsp: separate some requests from source.Identifier

Start to unwind source.Identifier by unrolling definition, type
definition, and call hierarchy handlers.

Along the way, introduce a couple primitive helper functions, which may
be made obsolete in the future but allowed preserving source.Identifier
behavior:
- referencedObject returns the object referenced by the cursor position,
  as defined by source.Identifier.
- mapPosition is a helper to map token.Pos to MappedRange in the narrow
  context of a package fileset.

After this change, the only remaining use of source.Identifier is for
Hover, but that is a sizeable refactoring and therefore left to a
subsequent CL.

Updates golang/go#57987

Change-Id: Iba4b0a574e6a6d3d54253f3b4bff8fe6e13a1b15
Reviewed-on: https://go-review.googlesource.com/c/tools/+/463955
gopls-CI: kokoro <noreply+kokoro@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/gopls/internal/lsp/source/view.go b/gopls/internal/lsp/source/view.go
index cbcc9b4e6..5f4e3f567 100644
--- a/gopls/internal/lsp/source/view.go
+++ b/gopls/internal/lsp/source/view.go
@@ -697,6 +697,23 @@ const (
 	Work
 )
 
+func (k FileKind) String() string {
+	switch k {
+	case Go:
+		return "go"
+	case Mod:
+		return "go.mod"
+	case Sum:
+		return "go.sum"
+	case Tmpl:
+		return "tmpl"
+	case Work:
+		return "go.work"
+	default:
+		return fmt.Sprintf("internal error: unknown file kind %d", k)
+	}
+}
+
 // Analyzer represents a go/analysis analyzer with some boolean properties
 // that let the user know how to use the analyzer.
 type Analyzer struct {