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cmd/gc: clearer error for defer/go of conversion or invalid function call 

Fixes #4654.

R=ken2
CC=golang-dev
https://golang.org/cl/7229072
This commit is contained in:
Russ Cox 2013-02-01 21:02:15 -05:00
parent b396d1143b
commit 79a16a3b70
5 changed files with 192 additions and 36 deletions
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29
src/cmd/gc/const.c
View File

@ -469,6 +469,20 @@ isconst(Node *n, int ct)
return t == ct || (ct == CTINT && t == CTRUNE);
}
static Node*
saveorig(Node *n)
{
Node *n1;
if(n == n->orig) {
// duplicate node for n->orig.
n1 = nod(OLITERAL, N, N);
n->orig = n1;
*n1 = *n;
}
return n->orig;
}
/*
* if n is constant, rewrite as OLITERAL node.
*/
@ -934,15 +948,14 @@ unary:
}
ret:
if(n == n->orig) {
// duplicate node for n->orig.
norig = nod(OLITERAL, N, N);
*norig = *n;
} else
norig = n->orig;
norig = saveorig(n);
*n = *nl;
// restore value of n->orig.
n->orig = norig;
if(norig->op == OCONV) {
dump("N", n);
dump("NORIG", norig);
}
n->val = v;
// check range.
@ -956,11 +969,15 @@ ret:
return;
settrue:
norig = saveorig(n);
*n = *nodbool(1);
n->orig = norig;
return;
setfalse:
norig = saveorig(n);
*n = *nodbool(0);
n->orig = norig;
return;
}

14
src/cmd/gc/fmt.c
View File

@ -381,7 +381,13 @@ Vconv(Fmt *fp)
case CTCPLX:
if((fp->flags & FmtSharp) || fmtmode == FExp)
return fmtprint(fp, "(%F+%Fi)", &v->u.cval->real, &v->u.cval->imag);
return fmtprint(fp, "(%#F + %#Fi)", &v->u.cval->real, &v->u.cval->imag);
if(mpcmpfltc(&v->u.cval->real, 0) == 0)
return fmtprint(fp, "%#Fi", &v->u.cval->imag);
if(mpcmpfltc(&v->u.cval->imag, 0) == 0)
return fmtprint(fp, "%#F", &v->u.cval->real);
if(mpcmpfltc(&v->u.cval->imag, 0) < 0)
return fmtprint(fp, "(%#F%#Fi)", &v->u.cval->real, &v->u.cval->imag);
return fmtprint(fp, "(%#F+%#Fi)", &v->u.cval->real, &v->u.cval->imag);
case CTSTR:
return fmtprint(fp, "\"%Z\"", v->u.sval);
case CTBOOL:
@ -391,7 +397,7 @@ Vconv(Fmt *fp)
case CTNIL:
return fmtstrcpy(fp, "nil");
}
return fmtprint(fp, "<%d>", v->ctype);
return fmtprint(fp, "<ctype=%d>", v->ctype);
}
// Fmt "%Z": escaped string literals
@ -1110,8 +1116,8 @@ exprfmt(Fmt *f, Node *n, int prec)
case OLITERAL: // this is a bit of a mess
if(fmtmode == FErr && n->sym != S)
return fmtprint(f, "%S", n->sym);
if(n->val.ctype == CTNIL && n->orig != N)
n = n->orig; // if this node was a nil decorated with at type, print the original naked nil
if(n->val.ctype == CTNIL && n->orig != N && n->orig != n)
return exprfmt(f, n->orig, prec);
if(n->type != T && n->type != types[n->type->etype] && n->type != idealbool && n->type != idealstring) {
// Need parens when type begins with what might
// be misinterpreted as a unary operator: * or <-.

70
src/cmd/gc/typecheck.c
View File

@ -31,6 +31,7 @@ static void checkassign(Node*);
static void checkassignlist(NodeList*);
static void stringtoarraylit(Node**);
static Node* resolve(Node*);
static void checkdefergo(Node*);
static NodeList* typecheckdefstack;
@ -1122,10 +1123,12 @@ reswitch:
if(!iscomplex[t->etype])
goto badcall1;
if(isconst(l, CTCPLX)){
r = n;
if(n->op == OREAL)
n = nodfltconst(&l->val.u.cval->real);
else
n = nodfltconst(&l->val.u.cval->imag);
n->orig = r;
}
n->type = types[cplxsubtype(t->etype)];
goto ret;
@ -1185,7 +1188,9 @@ reswitch:
}
if(l->op == OLITERAL && r->op == OLITERAL) {
// make it a complex literal
n = nodcplxlit(l->val, r->val);
r = nodcplxlit(l->val, r->val);
r->orig = n;
n = r;
}
n->type = t;
goto ret;
@ -1336,6 +1341,10 @@ reswitch:
switch(n->op) {
case OCONVNOP:
if(n->left->op == OLITERAL) {
r = nod(OXXX, N, N);
n->op = OCONV;
n->orig = r;
*r = *n;
n->op = OLITERAL;
n->val = n->left->val;
}
@ -1539,12 +1548,15 @@ reswitch:
case ODEFER:
ok |= Etop;
typecheck(&n->left, Etop);
typecheck(&n->left, Etop|Erv);
if(!n->left->diag)
checkdefergo(n);
goto ret;
case OPROC:
ok |= Etop;
typecheck(&n->left, Etop|Eproc);
typecheck(&n->left, Etop|Eproc|Erv);
checkdefergo(n);
goto ret;
case OFOR:
@ -1664,7 +1676,7 @@ ret:
}
if((top & Etop) && !(top & (Ecall|Erv|Etype)) && !(ok & Etop)) {
if(n->diag == 0) {
yyerror("%N not used", n);
yyerror("%N evaluated but not used", n);
n->diag = 1;
}
goto error;
@ -1687,6 +1699,56 @@ out:
*np = n;
}
static void
checkdefergo(Node *n)
{
char *what;
what = "defer";
if(n->op == OPROC)
what = "go";
switch(n->left->op) {
case OCALLINTER:
case OCALLMETH:
case OCALLFUNC:
case OCLOSE:
case OCOPY:
case ODELETE:
case OPANIC:
case OPRINT:
case OPRINTN:
case ORECOVER:
// ok
break;
case OAPPEND:
case OCAP:
case OCOMPLEX:
case OIMAG:
case OLEN:
case OMAKE:
case OMAKESLICE:
case OMAKECHAN:
case OMAKEMAP:
case ONEW:
case OREAL:
case OLITERAL: // conversion or unsafe.Alignof, Offsetof, Sizeof
if(n->left->orig != N && n->left->orig->op == OCONV)
goto conv;
yyerror("%s discards result of %N", what, n->left);
break;
default:
conv:
if(!n->diag) {
// The syntax made sure it was a call, so this must be
// a conversion.
n->diag = 1;
yyerror("%s requires function call, not conversion", what);
}
break;
}
}
static void
implicitstar(Node **nn)
{

44
test/fixedbugs/issue4463.go
View File

@ -45,17 +45,17 @@ func F() {
(println("bar"))
(recover())
go append(a, 0) // ERROR "not used"
go cap(a) // ERROR "not used"
go complex(1, 2) // ERROR "not used"
go imag(1i) // ERROR "not used"
go len(a) // ERROR "not used"
go make([]int, 10) // ERROR "not used"
go new(int) // ERROR "not used"
go real(1i) // ERROR "not used"
go unsafe.Alignof(a) // ERROR "not used"
go unsafe.Offsetof(s.f) // ERROR "not used"
go unsafe.Sizeof(a) // ERROR "not used"
go append(a, 0) // ERROR "discards result"
go cap(a) // ERROR "discards result"
go complex(1, 2) // ERROR "discards result"
go imag(1i) // ERROR "discards result"
go len(a) // ERROR "discards result"
go make([]int, 10) // ERROR "discards result"
go new(int) // ERROR "discards result"
go real(1i) // ERROR "discards result"
go unsafe.Alignof(a) // ERROR "discards result"
go unsafe.Offsetof(s.f) // ERROR "discards result"
go unsafe.Sizeof(a) // ERROR "discards result"
go close(c)
go copy(a, a)
@ -65,17 +65,17 @@ func F() {
go println("bar")
go recover()
defer append(a, 0) // ERROR "not used"
defer cap(a) // ERROR "not used"
defer complex(1, 2) // ERROR "not used"
defer imag(1i) // ERROR "not used"
defer len(a) // ERROR "not used"
defer make([]int, 10) // ERROR "not used"
defer new(int) // ERROR "not used"
defer real(1i) // ERROR "not used"
defer unsafe.Alignof(a) // ERROR "not used"
defer unsafe.Offsetof(s.f) // ERROR "not used"
defer unsafe.Sizeof(a) // ERROR "not used"
defer append(a, 0) // ERROR "discards result"
defer cap(a) // ERROR "discards result"
defer complex(1, 2) // ERROR "discards result"
defer imag(1i) // ERROR "discards result"
defer len(a) // ERROR "discards result"
defer make([]int, 10) // ERROR "discards result"
defer new(int) // ERROR "discards result"
defer real(1i) // ERROR "discards result"
defer unsafe.Alignof(a) // ERROR "discards result"
defer unsafe.Offsetof(s.f) // ERROR "discards result"
defer unsafe.Sizeof(a) // ERROR "discards result"
defer close(c)
defer copy(a, a)

71
test/fixedbugs/issue4654.go Normal file
View File

@ -0,0 +1,71 @@
// errorcheck
// Copyright 2013 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.
// Issue 4654.
// Check error for conversion and 'not used' in defer/go.
package p
import "unsafe"
func f() {
defer int(0) // ERROR "defer requires function call, not conversion"
go string([]byte("abc")) // ERROR "go requires function call, not conversion"
var c complex128
var f float64
var t struct {X int}
var x []int
defer append(x, 1) // ERROR "defer discards result of append"
defer cap(x) // ERROR "defer discards result of cap"
defer complex(1, 2) // ERROR "defer discards result of complex"
defer complex(f, 1) // ERROR "defer discards result of complex"
defer imag(1i) // ERROR "defer discards result of imag"
defer imag(c) // ERROR "defer discards result of imag"
defer len(x) // ERROR "defer discards result of len"
defer make([]int, 1) // ERROR "defer discards result of make"
defer make(chan bool) // ERROR "defer discards result of make"
defer make(map[string]int) // ERROR "defer discards result of make"
defer new(int) // ERROR "defer discards result of new"
defer real(1i) // ERROR "defer discards result of real"
defer real(c) // ERROR "defer discards result of real"
defer append(x, 1) // ERROR "defer discards result of append"
defer append(x, 1) // ERROR "defer discards result of append"
defer unsafe.Alignof(t.X) // ERROR "defer discards result of unsafe.Alignof"
defer unsafe.Offsetof(t.X) // ERROR "defer discards result of unsafe.Offsetof"
defer unsafe.Sizeof(t) // ERROR "defer discards result of unsafe.Sizeof"
defer copy(x, x) // ok
m := make(map[int]int)
defer delete(m, 1) // ok
defer panic(1) // ok
defer print(1) // ok
defer println(1) // ok
defer recover() // ok
int(0) // ERROR "int\(0\) not used"
string([]byte("abc")) // ERROR "string\(\[\]byte literal\) not used"
append(x, 1) // ERROR "not used"
cap(x) // ERROR "not used"
complex(1, 2) // ERROR "not used"
complex(f, 1) // ERROR "not used"
imag(1i) // ERROR "not used"
imag(c) // ERROR "not used"
len(x) // ERROR "not used"
make([]int, 1) // ERROR "not used"
make(chan bool) // ERROR "not used"
make(map[string]int) // ERROR "not used"
new(int) // ERROR "not used"
real(1i) // ERROR "not used"
real(c) // ERROR "not used"
append(x, 1) // ERROR "not used"
append(x, 1) // ERROR "not used"
unsafe.Alignof(t.X) // ERROR "not used"
unsafe.Offsetof(t.X) // ERROR "not used"
unsafe.Sizeof(t) // ERROR "not used"
}