From be28caf0aa1649c4422f64e687a388a027686e6e Mon Sep 17 00:00:00 2001
From: Robert Griesemer <gri@golang.org>
Date: Mon, 26 Apr 2021 12:50:44 -0700
Subject: [PATCH] cmd/compile/internal/types2: respect IgnoreFuncBodies for
 function literals

Updates #45783.

Change-Id: Id552a60f262e2da62125acd6aec0901a82f5a29a
Reviewed-on: https://go-review.googlesource.com/c/go/+/313650
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
---
 src/cmd/compile/internal/types2/expr.go | 26 +++++++++++++------------
 src/cmd/compile/internal/types2/stmt.go |  4 ++++
 2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/src/cmd/compile/internal/types2/expr.go b/src/cmd/compile/internal/types2/expr.go
index 76c6e7a3b30..8dbe6ea5379 100644
--- a/src/cmd/compile/internal/types2/expr.go
+++ b/src/cmd/compile/internal/types2/expr.go
@@ -1132,18 +1132,20 @@ func (check *Checker) exprInternal(x *operand, e syntax.Expr, hint Type) exprKin
 
 	case *syntax.FuncLit:
 		if sig, ok := check.typ(e.Type).(*Signature); ok {
-			// Anonymous functions are considered part of the
-			// init expression/func declaration which contains
-			// them: use existing package-level declaration info.
-			decl := check.decl // capture for use in closure below
-			iota := check.iota // capture for use in closure below (#22345)
-			// Don't type-check right away because the function may
-			// be part of a type definition to which the function
-			// body refers. Instead, type-check as soon as possible,
-			// but before the enclosing scope contents changes (#22992).
-			check.later(func() {
-				check.funcBody(decl, "<function literal>", sig, e.Body, iota)
-			})
+			if !check.conf.IgnoreFuncBodies && e.Body != nil {
+				// Anonymous functions are considered part of the
+				// init expression/func declaration which contains
+				// them: use existing package-level declaration info.
+				decl := check.decl // capture for use in closure below
+				iota := check.iota // capture for use in closure below (#22345)
+				// Don't type-check right away because the function may
+				// be part of a type definition to which the function
+				// body refers. Instead, type-check as soon as possible,
+				// but before the enclosing scope contents changes (#22992).
+				check.later(func() {
+					check.funcBody(decl, "<function literal>", sig, e.Body, iota)
+				})
+			}
 			x.mode = value
 			x.typ = sig
 		} else {
diff --git a/src/cmd/compile/internal/types2/stmt.go b/src/cmd/compile/internal/types2/stmt.go
index 9e3a45b6a8c..c3e646c80c1 100644
--- a/src/cmd/compile/internal/types2/stmt.go
+++ b/src/cmd/compile/internal/types2/stmt.go
@@ -13,6 +13,10 @@ import (
 )
 
 func (check *Checker) funcBody(decl *declInfo, name string, sig *Signature, body *syntax.BlockStmt, iota constant.Value) {
+	if check.conf.IgnoreFuncBodies {
+		panic("internal error: function body not ignored")
+	}
+
 	if check.conf.Trace {
 		check.trace(body.Pos(), "--- %s: %s", name, sig)
 		defer func() {