description: Changes to the language
labels: ["Proposal", "v2", "LanguageChange"]
title: "proposal: Go 2: proposal title"


body:
  - type: markdown
    attributes:
      value: |
       ## Our process for evaluating language changes can be found [here](https://go.googlesource.com/proposal/+/refs/heads/master#language-changes)

  - type: dropdown
    id: author-go-experience
    attributes:
      label: "Go Programming Experience"

	{"(1<<63)>>2", "right shift of value with high bit set"},
	{"(1<<62)>>2", ""},
	{`'\x80'`, "illegal UTF-8 encoding for character constant"},
	{"(23*4", "missing closing paren"},
	{")23*4", "unexpected ) evaluating expression"},
	{"18446744073709551616", "value out of range"},
}

func TestBadExpr(t *testing.T) {
	for i, test := range badExprTests {
		err := runBadTest(i, test, t)
		if err == nil {

precision, and vice versa.
</p>


<h3 id="Order_of_evaluation">Order of evaluation</h3>

<p>
At package level, <a href="#Package_initialization">initialization dependencies</a>
determine the evaluation order of individual initialization expressions in
<a href="#Variable_declarations">variable declarations</a>.
Otherwise, when evaluating the <a href="#Operands">operands</a> of an
expression, assignment, or

		}
		return v
	case '+':
		return +p.floatExpr()
	case '-':
		return -p.floatExpr()
	case scanner.Float:
		return p.atof(tok.String())
	}
	p.errorf("unexpected %s evaluating float expression", tok)
	return 0
}

// term = factor | factor ('*' | '/' | '%' | '>>' | '<<' | '&') factor
func (p *Parser) term() uint64 {
	value := p.factor()
	for {
		switch p.peek() {

precision, and vice versa.
</p>


<h3 id="Order_of_evaluation">Order of evaluation</h3>

<p>
At package level, <a href="#Package_initialization">initialization dependencies</a>
determine the evaluation order of individual initialization expressions in
<a href="#Variable_declarations">variable declarations</a>.
Otherwise, when evaluating the <a href="#Operands">operands</a> of an
expression, assignment, or

</pre>

<h3 id="constants">Constants</h3>

<p>
Although the assembler takes its guidance from the Plan 9 assemblers,
it is a distinct program, so there are some differences.
One is in constant evaluation.
Constant expressions in the assembler are parsed using Go's operator
precedence, not the C-like precedence of the original.
Thus <code>3&amp;1&lt;&lt;2</code> is 4, not 0—it parses as <code>(3&amp;1)&lt;&lt;2</code>

defined as the partial order requirements set out by the <a href="/ref/spec">Go language specification</a>
for Go's control flow constructs as well as the <a href="/ref/spec#Order_of_evaluation">order of evaluation for expressions</a>.
</p>

<p>
A Go <i>program execution</i> is modeled as a set of goroutine executions,