exp/types: process ast.Fun in checkObj; fix variadic function building

Fixed creation of Func's, taking IsVariadic from parameter list rather
than results.

Updated checkObj to process ast.Fun objects.

R=gri
CC=golang-dev
https://golang.org/cl/6402046

src/pkg/exp/types/check.go

@@ -158,8 +158,8 @@ func (c *checker) makeType(x ast.Expr, cycleOk bool) (typ Type) {
 		return &Struct{Fields: fields, Tags: tags}
 
 	case *ast.FuncType:
-		params, _, _ := c.collectFields(token.FUNC, t.Params, true)
-		results, _, isVariadic := c.collectFields(token.FUNC, t.Results, true)
+		params, _, isVariadic := c.collectFields(token.FUNC, t.Params, true)
+		results, _, _ := c.collectFields(token.FUNC, t.Results, true)
 		return &Func{Recv: nil, Params: params, Results: results, IsVariadic: isVariadic}
 
 	case *ast.InterfaceType:
@@ -200,7 +200,21 @@ func (c *checker) checkObj(obj *ast.Object, ref bool) {
 		// TODO(gri) complete this
 
 	case ast.Fun:
-		// TODO(gri) complete this
+		fdecl := obj.Decl.(*ast.FuncDecl)
+		ftyp := c.makeType(fdecl.Type, ref).(*Func)
+		obj.Type = ftyp
+		if fdecl.Recv != nil {
+			recvField := fdecl.Recv.List[0]
+			if len(recvField.Names) > 0 {
+				ftyp.Recv = recvField.Names[0].Obj
+			} else {
+				ftyp.Recv = ast.NewObj(ast.Var, "_")
+				ftyp.Recv.Decl = recvField
+			}
+			c.checkObj(ftyp.Recv, ref)
+			// TODO(axw) add method to a list in the receiver type.
+		}
+		// TODO(axw) check function body, if non-nil.
 
 	default:
 		panic("unreachable")

src/pkg/exp/types/types_test.go

@@ -0,0 +1,67 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file contains tests verifying the types associated with an AST after
+// type checking.
+
+package types
+
+import (
+	"go/ast"
+	"go/parser"
+	"testing"
+)
+
+func checkSource(t *testing.T, src string) *ast.Package {
+	const filename = "<src>"
+	file, err := parser.ParseFile(fset, filename, src, parser.DeclarationErrors)
+	if err != nil {
+		t.Fatal(err)
+	}
+	files := map[string]*ast.File{filename: file}
+	pkg, err := ast.NewPackage(fset, files, GcImport, Universe)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = Check(fset, pkg)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return pkg
+}
+
+func TestVariadicFunctions(t *testing.T) {
+	pkg := checkSource(t, `
+package p
+func f1(arg ...int)
+func f2(arg1 string, arg2 ...int)
+func f3()
+func f4(arg int)
+	`)
+	f1 := pkg.Scope.Lookup("f1")
+	f2 := pkg.Scope.Lookup("f2")
+	for _, f := range [...](*ast.Object){f1, f2} {
+		ftype := f.Type.(*Func)
+		if !ftype.IsVariadic {
+			t.Errorf("expected %s to be variadic", f.Name)
+		}
+		param := ftype.Params[len(ftype.Params)-1]
+		if param.Type != Int {
+			t.Errorf("expected last parameter of %s to have type int, found %T", f.Name, param.Type)
+		}
+	}
+
+	f3 := pkg.Scope.Lookup("f3")
+	f4 := pkg.Scope.Lookup("f4")
+	for _, f := range [...](*ast.Object){f3, f4} {
+		ftype := f.Type.(*Func)
+		if ftype.IsVariadic {
+			t.Fatalf("expected %s to not be variadic", f.Name)
+		}
+	}
+	// TODO(axw) replace this function's innards with table driven tests.
+	// We should have a helper function that prints a type signature. Then
+	// we can have a table of function declarations and expected type
+	// signatures which can be easily expanded.
+}