gopls/internal/golang: fix panic in inlineOneVariable

I excluded selectors expr.field and expr.method, but
forgot about field references {field: ...} in composite
literals, which are of course also non-lexical references.

+ regression test

For golang/go#74347

Change-Id: I3edb148c1be88314a29dc004e5b07c48a2be58b8
Reviewed-on: https://go-review.googlesource.com/c/tools/+/711860
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Alan Donovan <adonovan@google.com>
Reviewed-by: Madeline Kalil <mkalil@google.com>

Author: adonovan

gopls/internal/golang/inline.go

@@ -240,10 +240,14 @@ func inlineVariableOne(pkg *cache.Package, pgf *parsego.File, start, end token.P
 		if obj1 == nil {
 			continue // undefined; or a def, not a use
 		}
+		if v, ok := obj1.(*types.Var); ok && v.IsField() {
+			continue // a field reference T{F: 0} is non-lexical
+		}
 		if internalastutil.NodeContains(curRHS.Node(), obj1.Pos()) {
 			continue // not free (id is defined within RHS)
 		}
 		_, obj2 := scope.LookupParent(id.Name, pos)
+		// Inv: obj2 is non-nil.
 		if obj1 != obj2 {
 			return nil, nil, fmt.Errorf("cannot inline variable: its initializer expression refers to %q, which is shadowed by the declaration at line %d", id.Name, safetoken.Position(pgf.Tok, obj2.Pos()).Line)
 		}

gopls/internal/test/marker/testdata/codeaction/inline-var-74347.txt

@@ -1,4 +1,4 @@
-This is a regressoon test of a crash in refactor.inline.variable.
+This is a regression test of a crash in refactor.inline.variable.
 
 -- go.mod --
 module example.com/a

gopls/internal/test/marker/testdata/codeaction/inline-var-74347b.txt

@@ -0,0 +1,25 @@
+This is regression test of a second crash in
+refactor.inline.variable covered by #74347.
+
+-- go.mod --
+module example.com/a
+go 1.18
+
+-- a/a.go --
+package a
+
+func _() {
+	type S struct{ F int }
+	x := S{F: 0}
+	_ = x //@codeaction("x", "refactor.inline.variable", result=out)
+}
+
+-- @out/a/a.go --
+package a
+
+func _() {
+	type S struct{ F int }
+	x := S{F: 0}
+	_ = S{F: 0} //@codeaction("x", "refactor.inline.variable", result=out)
+}
+