From: Matthew Dempsky <mdempsky@google.com>
Date: Sat, 19 Aug 2023 01:13:58 +0000 (-0700)
Subject: cmd/compile/internal/typecheck: simplify NewMethodExpr
X-Git-Tag: go1.22rc1~1189
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=3761e3fbfd1a1e40074cc123e1912007abfd0e92;p=gostls13.git

cmd/compile/internal/typecheck: simplify NewMethodExpr

This CL changes NewMethodExpr to directly construct the OMETHEXPR
node, instead of running through the generic OXDOT typechecking
machinery.

Change-Id: Ic2af0bab6ff1aef45e8463bccb1f69c50db68f65
Reviewed-on: https://go-review.googlesource.com/c/go/+/520919
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
---

diff --git a/src/cmd/compile/internal/typecheck/expr.go b/src/cmd/compile/internal/typecheck/expr.go
index 2d25f80473..7e4b9f5621 100644
--- a/src/cmd/compile/internal/typecheck/expr.go
+++ b/src/cmd/compile/internal/typecheck/expr.go
@@ -447,7 +447,7 @@ func tcDot(n *ir.SelectorExpr, top int) ir.Node {
 		}
 	}
 
-	n.X = typecheck(n.X, ctxExpr|ctxType)
+	n.X = Expr(n.X)
 	n.X = DefaultLit(n.X, nil)
 
 	t := n.X.Type()
@@ -458,7 +458,7 @@ func tcDot(n *ir.SelectorExpr, top int) ir.Node {
 	}
 
 	if n.X.Op() == ir.OTYPE {
-		return typecheckMethodExpr(n)
+		base.FatalfAt(n.Pos(), "use NewMethodExpr to construct OMETHEXPR")
 	}
 
 	if t.IsPtr() && !t.Elem().IsInterface() {
diff --git a/src/cmd/compile/internal/typecheck/typecheck.go b/src/cmd/compile/internal/typecheck/typecheck.go
index 3bd384a0a7..a272f2a86b 100644
--- a/src/cmd/compile/internal/typecheck/typecheck.go
+++ b/src/cmd/compile/internal/typecheck/typecheck.go
@@ -846,58 +846,32 @@ func Lookdot1(errnode ir.Node, s *types.Sym, t *types.Type, fs *types.Fields, do
 // NewMethodExpr returns an OMETHEXPR node representing method
 // expression "recv.sym".
 func NewMethodExpr(pos src.XPos, recv *types.Type, sym *types.Sym) *ir.SelectorExpr {
-	n := Expr(ir.NewSelectorExpr(pos, ir.OXDOT, ir.TypeNode(recv), sym)).(*ir.SelectorExpr)
-	base.Assert(n.Op() == ir.OMETHEXPR)
-	return n
-}
-
-// typecheckMethodExpr checks selector expressions (ODOT) where the
-// base expression is a type expression (OTYPE).
-func typecheckMethodExpr(n *ir.SelectorExpr) (res ir.Node) {
-	if base.EnableTrace && base.Flag.LowerT {
-		defer tracePrint("typecheckMethodExpr", n)(&res)
-	}
-
-	t := n.X.Type()
-
-	// Compute the method set for t.
+	// Compute the method set for recv.
 	var ms *types.Fields
-	if t.IsInterface() {
-		ms = t.AllMethods()
+	if recv.IsInterface() {
+		ms = recv.AllMethods()
 	} else {
-		mt := types.ReceiverBaseType(t)
+		mt := types.ReceiverBaseType(recv)
 		if mt == nil {
-			base.Errorf("%v undefined (type %v has no method %v)", n, t, n.Sel)
-			n.SetType(nil)
-			return n
+			base.FatalfAt(pos, "type %v has no receiver base type", recv)
 		}
 		CalcMethods(mt)
 		ms = mt.AllMethods()
 	}
 
-	s := n.Sel
-	m := Lookdot1(n, s, t, ms, 0)
+	m := Lookdot1(nil, sym, recv, ms, 0)
 	if m == nil {
-		if Lookdot1(n, s, t, ms, 1) != nil {
-			base.Errorf("%v undefined (cannot refer to unexported method %v)", n, s)
-		} else if _, ambig := dotpath(s, t, nil, false); ambig {
-			base.Errorf("%v undefined (ambiguous selector)", n) // method or field
-		} else {
-			base.Errorf("%v undefined (type %v has no method %v)", n, t, s)
-		}
-		n.SetType(nil)
-		return n
+		base.FatalfAt(pos, "type %v has no method %v", recv, sym)
 	}
 
-	if !types.IsMethodApplicable(t, m) {
-		base.Errorf("invalid method expression %v (needs pointer receiver: (*%v).%S)", n, t, s)
-		n.SetType(nil)
-		return n
+	if !types.IsMethodApplicable(recv, m) {
+		base.FatalfAt(pos, "invalid method expression %v.%v (needs pointer receiver)", recv, sym)
 	}
 
-	n.SetOp(ir.OMETHEXPR)
+	n := ir.NewSelectorExpr(pos, ir.OMETHEXPR, ir.TypeNode(recv), sym)
 	n.Selection = m
-	n.SetType(NewMethodType(m.Type, n.X.Type()))
+	n.SetType(NewMethodType(m.Type, recv))
+	n.SetTypecheck(1)
 	return n
 }