internal/lsp: show comments for grouped variable declarations

Fixes golang/go#36139

Change-Id: I8aaf1a5d65b8d66ea7bb350439cc960c7505307d
Reviewed-on: https://go-review.googlesource.com/c/tools/+/211637
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>

internal/lsp/source/hover.go

@@ -212,13 +212,16 @@ func formatGenDecl(node *ast.GenDecl, obj types.Object, typ types.Type) (*HoverI
 
 func formatVar(node ast.Spec, obj types.Object, decl *ast.GenDecl) *HoverInformation {
 	var fieldList *ast.FieldList
-	if spec, ok := node.(*ast.TypeSpec); ok {
+	switch spec := node.(type) {
+	case *ast.TypeSpec:
 		switch t := spec.Type.(type) {
 		case *ast.StructType:
 			fieldList = t.Fields
 		case *ast.InterfaceType:
 			fieldList = t.Methods
 		}
+	case *ast.ValueSpec:
+		return &HoverInformation{source: obj, comment: spec.Doc}
 	}
 	// If we have a struct or interface declaration,
 	// we need to match the object to the corresponding field or method.

internal/lsp/testdata/godef/a/a.go

@@ -8,6 +8,11 @@ import (
 	"sync"
 )
 
+var (
+	// x is a variable.
+	x string //@x,hover("x", x)
+)
+
 type A string //@A
 
 func AStuff() { //@AStuff

internal/lsp/testdata/godef/a/a.go.golden

@@ -75,7 +75,7 @@ func Random2(y int) int
 func Random2(y int) int
 ```
 -- err-definition --
-godef/a/a.go:18:6-9: defined here as ```go
+godef/a/a.go:23:6-9: defined here as ```go
 var err error
 ```
 -- err-definition-json --
@@ -83,14 +83,14 @@ var err error
 	"span": {
 		"uri": "file://godef/a/a.go",
 		"start": {
-			"line": 18,
+			"line": 23,
 			"column": 6,
-			"offset": 228
+			"offset": 287
 		},
 		"end": {
-			"line": 18,
+			"line": 23,
 			"column": 9,
-			"offset": 231
+			"offset": 290
 		}
 	},
 	"description": "```go\nvar err error\n```"
@@ -112,3 +112,9 @@ func(t Type, size ...IntegerType) Type
 ```go
 string
 ```
+-- x-hover --
+x is a variable\.
+
+```go
+var x string
+```

internal/lsp/testdata/godef/b/b.go.golden

@@ -1,5 +1,5 @@
 -- A-definition --
-godef/a/a.go:11:6-7: defined here as [`a.A` on pkg.go.dev](https://pkg.go.dev/golang.org/x/tools/internal/lsp/godef/a#A)
+godef/a/a.go:16:6-7: defined here as [`a.A` on pkg.go.dev](https://pkg.go.dev/golang.org/x/tools/internal/lsp/godef/a#A)
 
 ```go
 A string //@A
@@ -10,14 +10,14 @@ A string //@A
 	"span": {
 		"uri": "file://godef/a/a.go",
 		"start": {
-			"line": 11,
+			"line": 16,
 			"column": 6,
-			"offset": 100
+			"offset": 159
 		},
 		"end": {
-			"line": 11,
+			"line": 16,
 			"column": 7,
-			"offset": 101
+			"offset": 160
 		}
 	},
 	"description": "[`a.A` on pkg.go.dev](https://pkg.go.dev/golang.org/x/tools/internal/lsp/godef/a#A)\n\n```go\nA string //@A\n\n```"
@@ -61,7 +61,7 @@ package a ("golang.org/x/tools/internal/lsp/godef/a")
 package a ("golang.org/x/tools/internal/lsp/godef/a")
 ```
 -- AStuff-definition --
-godef/a/a.go:13:6-12: defined here as [`a.AStuff` on pkg.go.dev](https://pkg.go.dev/golang.org/x/tools/internal/lsp/godef/a#AStuff)
+godef/a/a.go:18:6-12: defined here as [`a.AStuff` on pkg.go.dev](https://pkg.go.dev/golang.org/x/tools/internal/lsp/godef/a#AStuff)
 
 ```go
 func a.AStuff()
@@ -71,14 +71,14 @@ func a.AStuff()
 	"span": {
 		"uri": "file://godef/a/a.go",
 		"start": {
-			"line": 13,
+			"line": 18,
 			"column": 6,
-			"offset": 120
+			"offset": 179
 		},
 		"end": {
-			"line": 13,
+			"line": 18,
 			"column": 12,
-			"offset": 126
+			"offset": 185
 		}
 	},
 	"description": "[`a.AStuff` on pkg.go.dev](https://pkg.go.dev/golang.org/x/tools/internal/lsp/godef/a#AStuff)\n\n```go\nfunc a.AStuff()\n```"

internal/lsp/testdata/summary.txt.golden

@@ -11,7 +11,7 @@ FoldingRangesCount = 2
 FormatCount = 6
 ImportCount = 7
 SuggestedFixCount = 1
-DefinitionsCount = 42
+DefinitionsCount = 43
 TypeDefinitionsCount = 2
 HighlightsCount = 44
 ReferencesCount = 7