// errorcheck // Copyright 2011 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. // Verify goto semantics. // Does not compile. // // Each test is in a separate function just so that if the // compiler stops processing after one error, we don't // lose other ones. package main var ( i, n int x []int c chan int m map[int]int s string ) // goto after declaration okay func _() { x := 1 goto L L: _ = x } // goto before declaration okay func _() { goto L L: x := 1 _ = x } // goto across declaration not okay func _() { goto L // ERROR "goto L jumps over declaration of x at LINE+1|goto jumps over declaration" x := 1 // GCCGO_ERROR "defined here" _ = x L: } // goto across declaration in inner scope okay func _() { goto L { x := 1 _ = x } L: } // goto across declaration after inner scope not okay func _() { goto L // ERROR "goto L jumps over declaration of x at LINE+5|goto jumps over declaration" { x := 1 _ = x } x := 1 // GCCGO_ERROR "defined here" _ = x L: } // goto across declaration in reverse okay func _() { L: x := 1 _ = x goto L } // error shows first offending variable func _() { goto L // ERROR "goto L jumps over declaration of y at LINE+3|goto jumps over declaration" x := 1 // GCCGO_ERROR "defined here" _ = x y := 1 _ = y L: } // goto not okay even if code path is dead func _() { goto L // ERROR "goto L jumps over declaration of y at LINE+3|goto jumps over declaration" x := 1 // GCCGO_ERROR "defined here" _ = x y := 1 _ = y return L: } // goto into outer block okay func _() { { goto L } L: } // goto backward into outer block okay func _() { L: { goto L } } // goto into inner block not okay func _() { goto L // ERROR "goto L jumps into block starting at LINE+1|goto jumps into block" { // GCCGO_ERROR "block starts here" L: } } // goto backward into inner block still not okay func _() { { // GCCGO_ERROR "block starts here" L: } goto L // ERROR "goto L jumps into block starting at LINE-3|goto jumps into block" } // error shows first (outermost) offending block func _() { goto L // ERROR "goto L jumps into block starting at LINE+3|goto jumps into block" { { { // GCCGO_ERROR "block starts here" L: } } } } // error prefers block diagnostic over declaration diagnostic func _() { goto L // ERROR "goto L jumps into block starting at LINE+3|goto jumps into block" x := 1 _ = x { // GCCGO_ERROR "block starts here" L: } } // many kinds of blocks, all invalid to jump into or among, // but valid to jump out of // if func _() { L: if true { goto L } } func _() { L: if true { goto L } else { } } func _() { L: if false { } else { goto L } } func _() { goto L // ERROR "goto L jumps into block starting at LINE+1|goto jumps into block" if true { // GCCGO_ERROR "block starts here" L: } } func _() { goto L // ERROR "goto L jumps into block starting at LINE+1|goto jumps into block" if true { // GCCGO_ERROR "block starts here" L: } else { } } func _() { goto L // ERROR "goto L jumps into block starting at LINE+2|goto jumps into block" if true { } else { // GCCGO_ERROR "block starts here" L: } } func _() { if false { // GCCGO_ERROR "block starts here" L: } else { goto L // ERROR "goto L jumps into block starting at LINE-3|goto jumps into block" } } func _() { if true { goto L // ERROR "goto L jumps into block starting at LINE+1|goto jumps into block" } else { // GCCGO_ERROR "block starts here" L: } } func _() { if true { goto L // ERROR "goto L jumps into block starting at LINE+1|goto jumps into block" } else if false { // GCCGO_ERROR "block starts here" L: } } func _() { if true { goto L // ERROR "goto L jumps into block starting at LINE+1|goto jumps into block" } else if false { // GCCGO_ERROR "block starts here" L: } else { } } func _() { // This one is tricky. There is an implicit scope // starting at the second if statement, and it contains // the final else, so the outermost offending scope // really is LINE+1 (like in the previous test), // even though it looks like it might be LINE+3 instead. if true { goto L // ERROR "goto L jumps into block starting at LINE+2|goto jumps into block" } else if false { } else { // GCCGO_ERROR "block starts here" L: } } /* Want to enable these tests but gofmt mangles them. Issue 1972. func _() { // This one is okay, because the else is in the // implicit whole-if block and has no inner block // (no { }) around it. if true { goto L } else L: } func _() { // Still not okay. if true { //// GCCGO_ERROR "block starts here" L: } else goto L //// ERROR "goto L jumps into block starting at LINE-3|goto jumps into block" } */ // for func _() { for { goto L } L: } func _() { for { goto L L: } } func _() { for { // GCCGO_ERROR "block starts here" L: } goto L // ERROR "goto L jumps into block starting at LINE-3|goto jumps into block" } func _() { for { // GCCGO_ERROR "block starts here" goto L L1: } L: goto L1 // ERROR "goto L1 jumps into block starting at LINE-5|goto jumps into block" } func _() { for i < n { // GCCGO_ERROR "block starts here" L: } goto L // ERROR "goto L jumps into block starting at LINE-3|goto jumps into block" } func _() { for i = 0; i < n; i++ { // GCCGO_ERROR "block starts here" L: } goto L // ERROR "goto L jumps into block starting at LINE-3|goto jumps into block" } func _() { for i = range x { // GCCGO_ERROR "block starts here" L: } goto L // ERROR "goto L jumps into block starting at LINE-3|goto jumps into block" } func _() { for i = range c { // GCCGO_ERROR "block starts here" L: } goto L // ERROR "goto L jumps into block starting at LINE-3|goto jumps into block" } func _() { for i = range m { // GCCGO_ERROR "block starts here" L: } goto L // ERROR "goto L jumps into block starting at LINE-3|goto jumps into block" } func _() { for i = range s { // GCCGO_ERROR "block starts here" L: } goto L // ERROR "goto L jumps into block starting at LINE-3|goto jumps into block" } // switch func _() { L: switch i { case 0: goto L } } func _() { L: switch i { case 0: default: goto L } } func _() { switch i { case 0: default: L: goto L } } func _() { switch i { case 0: default: goto L L: } } func _() { switch i { case 0: goto L L: ; default: } } func _() { goto L // ERROR "goto L jumps into block starting at LINE+2|goto jumps into block" switch i { case 0: L: // GCCGO_ERROR "block starts here" } } func _() { goto L // ERROR "goto L jumps into block starting at LINE+2|goto jumps into block" switch i { case 0: L: // GCCGO_ERROR "block starts here" ; default: } } func _() { goto L // ERROR "goto L jumps into block starting at LINE+3|goto jumps into block" switch i { case 0: default: L: // GCCGO_ERROR "block starts here" } } func _() { switch i { default: goto L // ERROR "goto L jumps into block starting at LINE+1|goto jumps into block" case 0: L: // GCCGO_ERROR "block starts here" } } func _() { switch i { case 0: L: // GCCGO_ERROR "block starts here" ; default: goto L // ERROR "goto L jumps into block starting at LINE-4|goto jumps into block" } } // select // different from switch. the statement has no implicit block around it. func _() { L: select { case <-c: goto L } } func _() { L: select { case c <- 1: default: goto L } } func _() { select { case <-c: default: L: goto L } } func _() { select { case c <- 1: default: goto L L: } } func _() { select { case <-c: goto L L: ; default: } } func _() { goto L // ERROR "goto L jumps into block starting at LINE+2|goto jumps into block" select { case c <- 1: L: // GCCGO_ERROR "block starts here" } } func _() { goto L // ERROR "goto L jumps into block starting at LINE+2|goto jumps into block" select { case c <- 1: L: // GCCGO_ERROR "block starts here" ; default: } } func _() { goto L // ERROR "goto L jumps into block starting at LINE+3|goto jumps into block" select { case <-c: default: L: // GCCGO_ERROR "block starts here" } } func _() { select { default: goto L // ERROR "goto L jumps into block starting at LINE+1|goto jumps into block" case <-c: L: // GCCGO_ERROR "block starts here" } } func _() { select { case <-c: L: // GCCGO_ERROR "block starts here" ; default: goto L // ERROR "goto L jumps into block starting at LINE-4|goto jumps into block" } }