From e7219cc093aca07bdb7179fa1a42d44e56eaf9d4 Mon Sep 17 00:00:00 2001
From: Matthew Dempsky <mdempsky@google.com>
Date: Fri, 24 Jun 2022 14:19:06 -0700
Subject: [dev.unified] cmd/compile/internal/noder: refactor N:1 expression
 handling

Pull all multi-value expression handling logic into a new multiExpr
helper method.

Change-Id: I78ec2dfc523abcfa3368a1064df7045aade8e468
Reviewed-on: https://go-review.googlesource.com/c/go/+/415243
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
---
 src/cmd/compile/internal/noder/reader.go | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

(limited to 'src/cmd/compile/internal/noder/reader.go')

diff --git a/src/cmd/compile/internal/noder/reader.go b/src/cmd/compile/internal/noder/reader.go
index c8ed8552cd..ea1465693c 100644
--- a/src/cmd/compile/internal/noder/reader.go
+++ b/src/cmd/compile/internal/noder/reader.go
@@ -1240,7 +1240,7 @@ func (r *reader) stmt1(tag codeStmt, out *ir.Nodes) ir.Node {
 		pos := r.pos()
 
 		names, lhs := r.assignList()
-		rhs := r.exprList()
+		rhs := r.multiExpr()
 
 		if len(rhs) == 0 {
 			for _, name := range names {
@@ -1308,7 +1308,7 @@ func (r *reader) stmt1(tag codeStmt, out *ir.Nodes) ir.Node {
 
 	case stmtReturn:
 		pos := r.pos()
-		results := r.exprList()
+		results := r.multiExpr()
 		return ir.NewReturnStmt(pos, results)
 
 	case stmtSelect:
@@ -1734,15 +1734,8 @@ func (r *reader) expr() (res ir.Node) {
 			fun = typecheck.Callee(ir.NewSelectorExpr(pos, ir.OXDOT, fun, sym))
 		}
 		pos := r.pos()
-		var args ir.Nodes
-		var dots bool
-		if r.Bool() { // f(g())
-			call := r.expr()
-			args = []ir.Node{call}
-		} else {
-			args = r.exprs()
-			dots = r.Bool()
-		}
+		args := r.multiExpr()
+		dots := r.Bool()
 		n := typecheck.Call(pos, fun, args, dots)
 		switch n.Op() {
 		case ir.OAPPEND:
@@ -1814,6 +1807,20 @@ func (r *reader) optExpr() ir.Node {
 	return nil
 }
 
+func (r *reader) multiExpr() []ir.Node {
+	r.Sync(pkgbits.SyncMultiExpr)
+
+	exprs := make([]ir.Node, r.Len())
+	if len(exprs) == 0 {
+		return nil
+	}
+
+	for i := range exprs {
+		exprs[i] = r.expr()
+	}
+	return exprs
+}
+
 func (r *reader) compLit() ir.Node {
 	r.Sync(pkgbits.SyncCompLit)
 	pos := r.pos()
-- 
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