[dev.regabi] cmd/compile: merge {Selector,CallPart,Method}Expr

These three expression nodes all represent the same syntax, and so
they're represented the same within types2. And also they're not
handled that meaningfully differently throughout the rest of the
compiler to merit unique representations.

Method expressions are somewhat unique today that they're very
frequently turned into plain function names. But eventually that can
be handled by a post-typecheck desugaring phase that reduces the
number of redundant AST forms.

Passes toolstash -cmp.

Change-Id: I20df91bbd0d885c1f18ec67feb61ae1558670719
Reviewed-on: https://go-review.googlesource.com/c/go/+/280636
Trust: Matthew Dempsky <mdempsky@google.com>
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/src/cmd/compile/internal/escape/escape.go b/src/cmd/compile/internal/escape/escape.go
index d8f0111d2d..7b4037e028 100644
--- a/src/cmd/compile/internal/escape/escape.go
+++ b/src/cmd/compile/internal/escape/escape.go
@@ -612,10 +612,10 @@ func (e *escape) exprSkipInit(k hole, n ir.Node) {
 		// Flow the receiver argument to both the closure and
 		// to the receiver parameter.
 
-		n := n.(*ir.CallPartExpr)
+		n := n.(*ir.SelectorExpr)
 		closureK := e.spill(k, n)
 
-		m := n.Method
+		m := n.Selection
 
 		// We don't know how the method value will be called
 		// later, so conservatively assume the result
@@ -1542,7 +1542,7 @@ func (e *escape) finish(fns []*ir.Func) {
 					n := n.(*ir.ClosureExpr)
 					n.SetTransient(true)
 				case ir.OCALLPART:
-					n := n.(*ir.CallPartExpr)
+					n := n.(*ir.SelectorExpr)
 					n.SetTransient(true)
 				case ir.OSLICELIT:
 					n := n.(*ir.CompLitExpr)
@@ -1863,7 +1863,7 @@ func HeapAllocReason(n ir.Node) string {
 	if n.Op() == ir.OCLOSURE && typecheck.ClosureType(n.(*ir.ClosureExpr)).Size() >= ir.MaxImplicitStackVarSize {
 		return "too large for stack"
 	}
-	if n.Op() == ir.OCALLPART && typecheck.PartialCallType(n.(*ir.CallPartExpr)).Size() >= ir.MaxImplicitStackVarSize {
+	if n.Op() == ir.OCALLPART && typecheck.PartialCallType(n.(*ir.SelectorExpr)).Size() >= ir.MaxImplicitStackVarSize {
 		return "too large for stack"
 	}