gopls/internal/golang: eliminate dot import: skip keyed fields

This CL fixes a bug in "eliminate dot import" that would cause
it to change field F in T{F: ...} to T{pkg.F: ...}.

+ test

Fixes golang/go#73960

Change-Id: I090dacf855ec04137b5995d22a0b6fafc3f32d61
Reviewed-on: https://go-review.googlesource.com/c/tools/+/678595
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Robert Findley <rfindley@google.com>

Author: adonovan

gopls/internal/golang/codeaction.go

@@ -17,6 +17,7 @@ import (
 	"strings"
 
 	"golang.org/x/tools/go/ast/astutil"
+	"golang.org/x/tools/go/ast/edge"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/gopls/internal/analysis/fillstruct"
 	"golang.org/x/tools/gopls/internal/analysis/fillswitch"
@@ -733,11 +734,15 @@ func refactorRewriteEliminateDotImport(ctx context.Context, req *codeActionsRequ
 			continue
 		}
 
-		// Only qualify unqualified identifiers (due to dot imports).
+		// Only qualify unqualified identifiers (due to dot imports)
+		// that reference package-level symbols.
 		// All other references to a symbol imported from another package
 		// are nested within a select expression (pkg.Foo, v.Method, v.Field).
-		if is[*ast.SelectorExpr](curId.Parent().Node()) {
-			continue
+		if ek, _ := curId.ParentEdge(); ek == edge.SelectorExpr_Sel {
+			continue // qualified identifier (pkg.X) or selector (T.X or e.X)
+		}
+		if !typesinternal.IsPackageLevel(use) {
+			continue // unqualified field reference T{X: ...}
 		}
 
 		// Make sure that the package name will not be shadowed by something else in scope.

gopls/internal/test/marker/testdata/codeaction/eliminate_dot_import.txt

@@ -1,7 +1,7 @@
 This test checks the behavior of the 'remove dot import' code action.
 
 -- go.mod --
-module golang.org/lsptests/removedotimport
+module example.com
 
 go 1.18
 
@@ -13,6 +13,7 @@ package dotimport
 import (
 	. "fmt" //@codeaction(`.`, "refactor.rewrite.eliminateDotImport", edit=a1)
 	. "bytes" //@codeaction(`.`, "refactor.rewrite.eliminateDotImport", edit=a2)
+	. "time" //@codeaction(`.`, "refactor.rewrite.eliminateDotImport", edit=a3)
 )
 
 var _ = a
@@ -22,19 +23,28 @@ func a() {
 
 	buf := NewBuffer(nil)
 	buf.Grow(10)
+
+	_ = Ticker{C: nil}
 }
 
 -- @a1/a.go --
 @@ -6 +6 @@
 -	. "fmt" //@codeaction(`.`, "refactor.rewrite.eliminateDotImport", edit=a1)
 +	"fmt" //@codeaction(`.`, "refactor.rewrite.eliminateDotImport", edit=a1)
-@@ -13 +13 @@
+@@ -14 +14 @@
 -	Println("hello")
 +	fmt.Println("hello")
 -- @a2/a.go --
 @@ -7 +7 @@
 -	. "bytes" //@codeaction(`.`, "refactor.rewrite.eliminateDotImport", edit=a2)
 +	"bytes" //@codeaction(`.`, "refactor.rewrite.eliminateDotImport", edit=a2)
-@@ -15 +15 @@
+@@ -16 +16 @@
 -	buf := NewBuffer(nil)
 +	buf := bytes.NewBuffer(nil)
+-- @a3/a.go --
+@@ -8 +8 @@
+-	. "time" //@codeaction(`.`, "refactor.rewrite.eliminateDotImport", edit=a3)
++	"time" //@codeaction(`.`, "refactor.rewrite.eliminateDotImport", edit=a3)
+@@ -19 +19 @@
+-	_ = Ticker{C: nil}
++	_ = time.Ticker{C: nil}