x/tools: use new astutil.EnclosingFile helper

Change-Id: Iec730e8decfee3d1cba818155c59ddb4ef001476
Reviewed-on: https://go-review.googlesource.com/c/tools/+/710715
Reviewed-by: Robert Findley <rfindley@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Alan Donovan <adonovan@google.com>

Author: adonovan

go/analysis/passes/inline/gofix.go

@@ -172,7 +172,7 @@ func (a *analyzer) inlineCall(call *ast.CallExpr, cur inspector.Cursor) {
 			a.pass.Reportf(call.Lparen, "invalid inlining candidate: cannot read source file: %v", err)
 			return
 		}
-		curFile := currentFile(cur)
+		curFile := astutil.EnclosingFile(cur)
 		caller := &inline.Caller{
 			Fset:    a.pass.Fset,
 			Types:   a.pass.Pkg,
@@ -251,7 +251,7 @@ func (a *analyzer) inlineAlias(tn *types.TypeName, curId inspector.Cursor) {
 	}
 	rhs := alias.Rhs()
 	curPath := a.pass.Pkg.Path()
-	curFile := currentFile(curId)
+	curFile := astutil.EnclosingFile(curId)
 	id := curId.Node().(*ast.Ident)
 	// We have an identifier A here (n), possibly qualified by a package
 	// identifier (sel.n), and an inlinable "type A = rhs" elsewhere.
@@ -425,7 +425,7 @@ func (a *analyzer) inlineConst(con *types.Const, cur inspector.Cursor) {
 	}
 
 	// If n is qualified by a package identifier, we'll need the full selector expression.
-	curFile := currentFile(cur)
+	curFile := astutil.EnclosingFile(cur)
 	n := cur.Node().(*ast.Ident)
 
 	// We have an identifier A here (n), possibly qualified by a package identifier (sel.X,
@@ -503,14 +503,6 @@ func (a *analyzer) readFile(node ast.Node) ([]byte, error) {
 	return content, nil
 }
 
-// currentFile returns the unique ast.File for a cursor.
-func currentFile(c inspector.Cursor) *ast.File {
-	for cf := range c.Enclosing((*ast.File)(nil)) {
-		return cf.Node().(*ast.File)
-	}
-	panic("no *ast.File enclosing a cursor: impossible")
-}
-
 // A goFixInlineFuncFact is exported for each function marked "//go:fix inline".
 // It holds information about the callee to support inlining.
 type goFixInlineFuncFact struct{ Callee *inline.Callee }

gopls/internal/analysis/unusedparams/unusedparams.go

@@ -16,6 +16,7 @@ import (
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/gopls/internal/util/moreslices"
 	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/astutil"
 	"golang.org/x/tools/internal/typesinternal"
 )
 
@@ -243,10 +244,8 @@ funcloop:
 
 		// Don't report diagnostics on generated files.
 		// (We can't skip analysis of generated files, though.)
-		for curFile := range c.Enclosing((*ast.File)(nil)) {
-			if ast.IsGenerated(curFile.Node().(*ast.File)) {
-				continue funcloop
-			}
+		if ast.IsGenerated(astutil.EnclosingFile(c)) {
+			continue funcloop
 		}
 
 		// Report each unused parameter.