go/parser: require label after goto

mateusz834 · mateusz834 · commit 272e0ea9fde1 · 2024-12-22T11:46:12.000+01:00
Change-Id: I0209f9d1870a2932dfbd347c252e3f9af055afd3
diff --git a/src/go/parser/parser.go b/src/go/parser/parser.go
@@ -2050,7 +2050,7 @@ func (p *parser) parseBranchStmt(tok token.Token) *ast.BranchStmt {
 
 	pos := p.expect(tok)
 	var label *ast.Ident
-	if tok != token.FALLTHROUGH && p.tok == token.IDENT {
+	if (tok != token.FALLTHROUGH && p.tok == token.IDENT) || tok == token.GOTO {
 		label = p.parseIdent()
 	}
 	p.expectSemi()
diff --git a/src/go/parser/short_test.go b/src/go/parser/short_test.go
@@ -204,6 +204,10 @@ var invalids = []string{
 	`package p; func (T) _[ /* ERROR "must have no type parameters" */ A, B C[A, B]](a A) B`,
 
 	`package p; func(*T[e, e /* ERROR "e redeclared" */ ]) _()`,
+
+	// go.dev/issue/70957
+	`package p; func f() {goto; /* ERROR "expected 'IDENT', found ';'" */ }`,
+	`package p; func f() {goto} /* ERROR "expected 'IDENT', found '}'" */ }`,
 }
 
 func TestInvalid(t *testing.T) {

Original file line number	Diff line number	Diff line change
`@@ -2050,7 +2050,7 @@ func (p parser) parseBranchStmt(tok token.Token) ast.BranchStmt {`
`2050`	`2050`
`2051`	`2051`	`pos := p.expect(tok)`
`2052`	`2052`	`var label *ast.Ident`
`2053`		`- if tok != token.FALLTHROUGH && p.tok == token.IDENT {`
	`2053`	`+ if (tok != token.FALLTHROUGH && p.tok == token.IDENT) \|\| tok == token.GOTO {`
`2054`	`2054`	`label = p.parseIdent()`
`2055`	`2055`	`}`
`2056`	`2056`	`p.expectSemi()`
Original file line number	Diff line number	Diff line change
`@@ -204,6 +204,10 @@ var invalids = []string{`
`204`	`204`	`package p; func (T) _[ /* ERROR "must have no type parameters" */ A, B C[A, B]](a A) B`,
`205`	`205`
`206`	`206`	`package p; func(T[e, e / ERROR "e redeclared" */ ]) _()`,
	`207`	`+`
	`208`	`+ // go.dev/issue/70957`
	`209`	+ `package p; func f() {goto; /* ERROR "expected 'IDENT', found ';'" */ }`,
	`210`	+ `package p; func f() {goto} /* ERROR "expected 'IDENT', found '}'" */ }`,
`207`	`211`	`}`
`208`	`212`
`209`	`213`	`func TestInvalid(t *testing.T) {`