1 files changed, 329 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/syntax/nodes_test.go b/src/cmd/compile/internal/syntax/nodes_test.go
new file mode 100644
index 0000000..a39f08c
--- /dev/null
+++ b/src/cmd/compile/internal/syntax/nodes_test.go
@@ -0,0 +1,329 @@
+// Copyright 2017 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.
+
+package syntax
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+)
+
+// A test is a source code snippet of a particular node type.
+// In the snippet, a '@' indicates the position recorded by
+// the parser when creating the respective node.
+type test struct {
+	nodetyp string
+	snippet string
+}
+
+var decls = []test{
+	// The position of declarations is always the
+	// position of the first token of an individual
+	// declaration, independent of grouping.
+	{"ImportDecl", `import @"math"`},
+	{"ImportDecl", `import @mymath "math"`},
+	{"ImportDecl", `import @. "math"`},
+	{"ImportDecl", `import (@"math")`},
+	{"ImportDecl", `import (@mymath "math")`},
+	{"ImportDecl", `import (@. "math")`},
+
+	{"ConstDecl", `const @x`},
+	{"ConstDecl", `const @x = 0`},
+	{"ConstDecl", `const @x, y, z = 0, 1, 2`},
+	{"ConstDecl", `const (@x)`},
+	{"ConstDecl", `const (@x = 0)`},
+	{"ConstDecl", `const (@x, y, z = 0, 1, 2)`},
+
+	{"TypeDecl", `type @T int`},
+	{"TypeDecl", `type @T = int`},
+	{"TypeDecl", `type (@T int)`},
+	{"TypeDecl", `type (@T = int)`},
+
+	{"VarDecl", `var @x int`},
+	{"VarDecl", `var @x, y, z int`},
+	{"VarDecl", `var @x int = 0`},
+	{"VarDecl", `var @x, y, z int = 1, 2, 3`},
+	{"VarDecl", `var @x = 0`},
+	{"VarDecl", `var @x, y, z = 1, 2, 3`},
+	{"VarDecl", `var (@x int)`},
+	{"VarDecl", `var (@x, y, z int)`},
+	{"VarDecl", `var (@x int = 0)`},
+	{"VarDecl", `var (@x, y, z int = 1, 2, 3)`},
+	{"VarDecl", `var (@x = 0)`},
+	{"VarDecl", `var (@x, y, z = 1, 2, 3)`},
+
+	{"FuncDecl", `func @f() {}`},
+	{"FuncDecl", `func @(T) f() {}`},
+	{"FuncDecl", `func @(x T) f() {}`},
+}
+
+var exprs = []test{
+	// The position of an expression is the position
+	// of the left-most token that identifies the
+	// kind of expression.
+	{"Name", `@x`},
+
+	{"BasicLit", `@0`},
+	{"BasicLit", `@0x123`},
+	{"BasicLit", `@3.1415`},
+	{"BasicLit", `@.2718`},
+	{"BasicLit", `@1i`},
+	{"BasicLit", `@'a'`},
+	{"BasicLit", `@"abc"`},
+	{"BasicLit", "@`abc`"},
+
+	{"CompositeLit", `@{}`},
+	{"CompositeLit", `T@{}`},
+	{"CompositeLit", `struct{x, y int}@{}`},
+
+	{"KeyValueExpr", `"foo"@: true`},
+	{"KeyValueExpr", `"a"@: b`},
+
+	{"FuncLit", `@func (){}`},
+	{"ParenExpr", `@(x)`},
+	{"SelectorExpr", `a@.b`},
+	{"IndexExpr", `a@[i]`},
+
+	{"SliceExpr", `a@[:]`},
+	{"SliceExpr", `a@[i:]`},
+	{"SliceExpr", `a@[:j]`},
+	{"SliceExpr", `a@[i:j]`},
+	{"SliceExpr", `a@[i:j:k]`},
+
+	{"AssertExpr", `x@.(T)`},
+
+	{"Operation", `@*b`},
+	{"Operation", `@+b`},
+	{"Operation", `@-b`},
+	{"Operation", `@!b`},
+	{"Operation", `@^b`},
+	{"Operation", `@&b`},
+	{"Operation", `@<-b`},
+
+	{"Operation", `a @|| b`},
+	{"Operation", `a @&& b`},
+	{"Operation", `a @== b`},
+	{"Operation", `a @+ b`},
+	{"Operation", `a @* b`},
+
+	{"CallExpr", `f@()`},
+	{"CallExpr", `f@(x, y, z)`},
+	{"CallExpr", `obj.f@(1, 2, 3)`},
+	{"CallExpr", `func(x int) int { return x + 1 }@(y)`},
+
+	// ListExpr: tested via multi-value const/var declarations
+}
+
+var types = []test{
+	{"Operation", `@*T`},
+	{"Operation", `@*struct{}`},
+
+	{"ArrayType", `@[10]T`},
+	{"ArrayType", `@[...]T`},
+
+	{"SliceType", `@[]T`},
+	{"DotsType", `@...T`},
+	{"StructType", `@struct{}`},
+	{"InterfaceType", `@interface{}`},
+	{"FuncType", `func@()`},
+	{"MapType", `@map[T]T`},
+
+	{"ChanType", `@chan T`},
+	{"ChanType", `@chan<- T`},
+	{"ChanType", `@<-chan T`},
+}
+
+var fields = []test{
+	{"Field", `@T`},
+	{"Field", `@(T)`},
+	{"Field", `@x T`},
+	{"Field", `@x *(T)`},
+	{"Field", `@x, y, z T`},
+	{"Field", `@x, y, z (*T)`},
+}
+
+var stmts = []test{
+	{"EmptyStmt", `@`},
+
+	{"LabeledStmt", `L@:`},
+	{"LabeledStmt", `L@: ;`},
+	{"LabeledStmt", `L@: f()`},
+
+	{"BlockStmt", `@{}`},
+
+	// The position of an ExprStmt is the position of the expression.
+	{"ExprStmt", `@<-ch`},
+	{"ExprStmt", `f@()`},
+	{"ExprStmt", `append@(s, 1, 2, 3)`},
+
+	{"SendStmt", `ch @<- x`},
+
+	{"DeclStmt", `@const x = 0`},
+	{"DeclStmt", `@const (x = 0)`},
+	{"DeclStmt", `@type T int`},
+	{"DeclStmt", `@type T = int`},
+	{"DeclStmt", `@type (T1 = int; T2 = float32)`},
+	{"DeclStmt", `@var x = 0`},
+	{"DeclStmt", `@var x, y, z int`},
+	{"DeclStmt", `@var (a, b = 1, 2)`},
+
+	{"AssignStmt", `x @= y`},
+	{"AssignStmt", `a, b, x @= 1, 2, 3`},
+	{"AssignStmt", `x @+= y`},
+	{"AssignStmt", `x @:= y`},
+	{"AssignStmt", `x, ok @:= f()`},
+	{"AssignStmt", `x@++`},
+	{"AssignStmt", `a[i]@--`},
+
+	{"BranchStmt", `@break`},
+	{"BranchStmt", `@break L`},
+	{"BranchStmt", `@continue`},
+	{"BranchStmt", `@continue L`},
+	{"BranchStmt", `@fallthrough`},
+	{"BranchStmt", `@goto L`},
+
+	{"CallStmt", `@defer f()`},
+	{"CallStmt", `@go f()`},
+
+	{"ReturnStmt", `@return`},
+	{"ReturnStmt", `@return x`},
+	{"ReturnStmt", `@return a, b, a + b*f(1, 2, 3)`},
+
+	{"IfStmt", `@if cond {}`},
+	{"IfStmt", `@if cond { f() } else {}`},
+	{"IfStmt", `@if cond { f() } else { g(); h() }`},
+	{"ForStmt", `@for {}`},
+	{"ForStmt", `@for { f() }`},
+	{"SwitchStmt", `@switch {}`},
+	{"SwitchStmt", `@switch { default: }`},
+	{"SwitchStmt", `@switch { default: x++ }`},
+	{"SelectStmt", `@select {}`},
+	{"SelectStmt", `@select { default: }`},
+	{"SelectStmt", `@select { default: ch <- false }`},
+}
+
+var ranges = []test{
+	{"RangeClause", `@range s`},
+	{"RangeClause", `i = @range s`},
+	{"RangeClause", `i := @range s`},
+	{"RangeClause", `_, x = @range s`},
+	{"RangeClause", `i, x = @range s`},
+	{"RangeClause", `_, x := @range s.f`},
+	{"RangeClause", `i, x := @range f(i)`},
+}
+
+var guards = []test{
+	{"TypeSwitchGuard", `x@.(type)`},
+	{"TypeSwitchGuard", `x := x@.(type)`},
+}
+
+var cases = []test{
+	{"CaseClause", `@case x:`},
+	{"CaseClause", `@case x, y, z:`},
+	{"CaseClause", `@case x == 1, y == 2:`},
+	{"CaseClause", `@default:`},
+}
+
+var comms = []test{
+	{"CommClause", `@case <-ch:`},
+	{"CommClause", `@case x <- ch:`},
+	{"CommClause", `@case x = <-ch:`},
+	{"CommClause", `@case x := <-ch:`},
+	{"CommClause", `@case x, ok = <-ch: f(1, 2, 3)`},
+	{"CommClause", `@case x, ok := <-ch: x++`},
+	{"CommClause", `@default:`},
+	{"CommClause", `@default: ch <- true`},
+}
+
+func TestPos(t *testing.T) {
+	// TODO(gri) Once we have a general tree walker, we can use that to find
+	// the first occurrence of the respective node and we don't need to hand-
+	// extract the node for each specific kind of construct.
+
+	testPos(t, decls, "package p; ", "",
+		func(f *File) Node { return f.DeclList[0] },
+	)
+
+	// embed expressions in a composite literal so we can test key:value and naked composite literals
+	testPos(t, exprs, "package p; var _ = T{ ", " }",
+		func(f *File) Node { return f.DeclList[0].(*VarDecl).Values.(*CompositeLit).ElemList[0] },
+	)
+
+	// embed types in a function  signature so we can test ... types
+	testPos(t, types, "package p; func f(", ")",
+		func(f *File) Node { return f.DeclList[0].(*FuncDecl).Type.ParamList[0].Type },
+	)
+
+	testPos(t, fields, "package p; func f(", ")",
+		func(f *File) Node { return f.DeclList[0].(*FuncDecl).Type.ParamList[0] },
+	)
+
+	testPos(t, stmts, "package p; func _() { ", "; }",
+		func(f *File) Node { return f.DeclList[0].(*FuncDecl).Body.List[0] },
+	)
+
+	testPos(t, ranges, "package p; func _() { for ", " {} }",
+		func(f *File) Node { return f.DeclList[0].(*FuncDecl).Body.List[0].(*ForStmt).Init.(*RangeClause) },
+	)
+
+	testPos(t, guards, "package p; func _() { switch ", " {} }",
+		func(f *File) Node { return f.DeclList[0].(*FuncDecl).Body.List[0].(*SwitchStmt).Tag.(*TypeSwitchGuard) },
+	)
+
+	testPos(t, cases, "package p; func _() { switch { ", " } }",
+		func(f *File) Node { return f.DeclList[0].(*FuncDecl).Body.List[0].(*SwitchStmt).Body[0] },
+	)
+
+	testPos(t, comms, "package p; func _() { select { ", " } }",
+		func(f *File) Node { return f.DeclList[0].(*FuncDecl).Body.List[0].(*SelectStmt).Body[0] },
+	)
+}
+
+func testPos(t *testing.T, list []test, prefix, suffix string, extract func(*File) Node) {
+	for _, test := range list {
+		// complete source, compute @ position, and strip @ from source
+		src, index := stripAt(prefix + test.snippet + suffix)
+		if index < 0 {
+			t.Errorf("missing @: %s (%s)", src, test.nodetyp)
+			continue
+		}
+
+		// build syntax tree
+		file, err := Parse(nil, strings.NewReader(src), nil, nil, 0)
+		if err != nil {
+			t.Errorf("parse error: %s: %v (%s)", src, err, test.nodetyp)
+			continue
+		}
+
+		// extract desired node
+		node := extract(file)
+		if typ := typeOf(node); typ != test.nodetyp {
+			t.Errorf("type error: %s: type = %s, want %s", src, typ, test.nodetyp)
+			continue
+		}
+
+		// verify node position with expected position as indicated by @
+		if pos := int(node.Pos().Col()); pos != index+colbase {
+			t.Errorf("pos error: %s: pos = %d, want %d (%s)", src, pos, index+colbase, test.nodetyp)
+			continue
+		}
+	}
+}
+
+func stripAt(s string) (string, int) {
+	if i := strings.Index(s, "@"); i >= 0 {
+		return s[:i] + s[i+1:], i
+	}
+	return s, -1
+}
+
+func typeOf(n Node) string {
+	const prefix = "*syntax."
+	k := fmt.Sprintf("%T", n)
+	if strings.HasPrefix(k, prefix) {
+		return k[len(prefix):]
+	}
+	return k
+}