cmd/compile: cleanup addmethod

Change-Id: Icb1671187d70edd962e2bda2cc45771b17a8e770
Reviewed-on: https://go-review.googlesource.com/28175
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/cmd/compile/internal/gc/dcl.go b/src/cmd/compile/internal/gc/dcl.go
index 48ba1f545ee62d5b46d9f2cdd7b5457ac6389525..ae5bb557aa8f5ad252651edaf874426278e003d9 100644 (file)
--- a/src/cmd/compile/internal/gc/dcl.go
+++ b/src/cmd/compile/internal/gc/dcl.go
@@ -1167,52 +1167,37 @@ func addmethod(msym *Sym, t *Type, tpkg *Pkg, local, nointerface bool) {
                return
        }
 
-       pa := rf.Type // base type
-       mt := methtype(pa)
+       mt := methtype(rf.Type)
        if mt == nil || mt.Sym == nil {
-               t = pa
-               if t == nil { // rely on typecheck having complained before
-                       return
-               }
-               if t != nil {
-                       if t.IsPtr() {
-                               if t.Sym != nil {
-                                       Yyerror("invalid receiver type %v (%v is a pointer type)", pa, t)
-                                       return
-                               }
-
-                               t = t.Elem()
-                       }
-
-                       if t.Broke { // rely on typecheck having complained before
-                               return
-                       }
-                       if t.Sym == nil {
-                               Yyerror("invalid receiver type %v (%v is an unnamed type)", pa, t)
-                               return
-                       }
-
-                       if t.IsPtr() {
+               pa := rf.Type
+               t := pa
+               if t != nil && t.IsPtr() {
+                       if t.Sym != nil {
                                Yyerror("invalid receiver type %v (%v is a pointer type)", pa, t)
                                return
                        }
-
-                       if t.IsInterface() {
-                               Yyerror("invalid receiver type %v (%v is an interface type)", pa, t)
-                               return
-                       }
+                       t = t.Elem()
                }
 
-               // Should have picked off all the reasons above,
-               // but just in case, fall back to generic error.
-               Yyerror("invalid receiver type %v (%v / %v)", pa, Tconv(pa, FmtLong), Tconv(t, FmtLong))
-
+               switch {
+               case t == nil || t.Broke:
+                       // rely on typecheck having complained before
+               case t.Sym == nil:
+                       Yyerror("invalid receiver type %v (%v is an unnamed type)", pa, t)
+               case t.IsPtr():
+                       Yyerror("invalid receiver type %v (%v is a pointer type)", pa, t)
+               case t.IsInterface():
+                       Yyerror("invalid receiver type %v (%v is an interface type)", pa, t)
+               default:
+                       // Should have picked off all the reasons above,
+                       // but just in case, fall back to generic error.
+                       Yyerror("invalid receiver type %v (%v / %v)", pa, Tconv(pa, FmtLong), Tconv(t, FmtLong))
+               }
                return
        }
 
-       pa = mt
-       if local && !pa.Local {
-               Yyerror("cannot define new methods on non-local type %v", pa)
+       if local && !mt.Local {
+               Yyerror("cannot define new methods on non-local type %v", mt)
                return
        }
 
@@ -1220,10 +1205,10 @@ func addmethod(msym *Sym, t *Type, tpkg *Pkg, local, nointerface bool) {
                return
        }
 
-       if pa.IsStruct() {
-               for _, f := range pa.Fields().Slice() {
+       if mt.IsStruct() {
+               for _, f := range mt.Fields().Slice() {
                        if f.Sym == msym {
-                               Yyerror("type %v has both field and method named %v", pa, msym)
+                               Yyerror("type %v has both field and method named %v", mt, msym)
                                return
                        }
                }
@@ -1232,14 +1217,14 @@ func addmethod(msym *Sym, t *Type, tpkg *Pkg, local, nointerface bool) {
        n := Nod(ODCLFIELD, newname(msym), nil)
        n.Type = t
 
-       for _, f := range pa.Methods().Slice() {
+       for _, f := range mt.Methods().Slice() {
                if msym.Name != f.Sym.Name {
                        continue
                }
                // Eqtype only checks that incoming and result parameters match,
                // so explicitly check that the receiver parameters match too.
                if !Eqtype(t, f.Type) || !Eqtype(t.Recv().Type, f.Type.Recv().Type) {
-                       Yyerror("method redeclared: %v.%v\n\t%v\n\t%v", pa, msym, f.Type, t)
+                       Yyerror("method redeclared: %v.%v\n\t%v\n\t%v", mt, msym, f.Type, t)
                }
                return
        }
@@ -1252,7 +1237,7 @@ func addmethod(msym *Sym, t *Type, tpkg *Pkg, local, nointerface bool) {
                Fatalf("imported method name %v in wrong package %s\n", sconv(f.Sym, FmtSign), tpkg.Name)
        }
 
-       pa.Methods().Append(f)
+       mt.Methods().Append(f)
 }
 
 func funccompile(n *Node) {