To install:

1) chrome://extensions/
2) click "[+] Developer Mode" in top right
3) "Load unpacked extension..."
4) pick $GOROOT/misc/chrome/gophertool

	// For now, assume that the only instance of capital C is when
	// used as the imported package identifier.
	// The parser should take care of scoping in the future, so
	// that we will be able to distinguish a "top-level C" from a
	// local C.
	if l, ok := sel.X.(*ast.Ident); !ok || l.Name != "C" {
		return
	}
	if context == ctxAssign2 {
		context = ctxExpr
	}
	if context == ctxEmbedType {

}

// hasPointer is used by needsPointerCheck. If top is true it returns
// whether t is or contains a pointer that might point to a pointer.
// If top is false it reports whether t is or contains a pointer.
// f may be nil.
func (p *Package) hasPointer(f *File, t ast.Expr, top bool) bool {
	switch t := t.(type) {
	case *ast.ArrayType:
		if t.Len == nil {
			if !top {
				return true
			}

// Copyright 2015 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 flags implements top-level flags and the usage message for the assembler.
package flags

import (
	"cmd/internal/obj"
	"cmd/internal/objabi"
	"flag"
	"fmt"
	"os"
	"path/filepath"
	"strings"
)

var (

generated by cgo. A typical preamble #includes necessary definitions:

	// #include <stdio.h>
	import "C"

For more details about the usage of cgo, see the documentation
comment at the top of this file.

Understanding C

Cgo scans the Go source files that import "C" for uses of that
package, such as C.puts. It collects all such identifiers. The next

	<li>The scope of a <a href="#Predeclared_identifiers">predeclared identifier</a> is the universe block.</li>

	<li>The scope of an identifier denoting a constant, type, variable,
	    or function (but not method) declared at top level (outside any
	    function) is the package block.</li>

	<li>The scope of the package name of an imported package is the file block
	    of the file containing the import declaration.</li>

		output = output[1:]
	}

	// Checked printing.
	// Now check machine code layout.

	top := pList.Firstpc
	var text *obj.LSym
	ok = true
	ctxt.DiagFunc = func(format string, args ...interface{}) {
		t.Errorf(format, args...)
		ok = false
	}
	obj.Flushplist(ctxt, pList, nil)

	for p := top; p != nil; p = p.Link {
		if p.As == obj.ATEXT {
			text = p.From.Sym
		}
		hexes := hexByLine[p.Line()]

func (in *Input) expectText(args ...interface{}) {
	in.Error(append(args, "; got", strconv.Quote(in.Stack.Text()))...)
}

// enabled reports whether the input is enabled by an ifdef, or is at the top level.
func (in *Input) enabled() bool {
	return len(in.ifdefStack) == 0 || in.ifdefStack[len(in.ifdefStack)-1]
}

func (in *Input) expectNewline(directive string) {
	tok := in.Stack.Next()
	if tok != '\n' {

	<li>The scope of a <a href="#Predeclared_identifiers">predeclared identifier</a> is the universe block.</li>

	<li>The scope of an identifier denoting a constant, type, variable,
	    or function (but not method) declared at top level (outside any
	    function) is the package block.</li>

	<li>The scope of the package name of an imported package is the file block
	    of the file containing the import declaration.</li>

programs listing versions of Go earlier than Go 1.20 are configured to match Go 1.20,
not the older version.

To override these defaults, a main package's source files
can include one or more `//go:debug` directives at the top of the file
(preceding the `package` statement).
Continuing the `panicnil` example, if the module or workspace is updated
to say `go` `1.21`, the program can opt back into the old `panic(nil)`
behavior by including this directive: