gc: clearer error for struct == struct
cmp6.go:48: invalid operation: t3 == t3 (operator == not defined on struct)
Fixes #1438.
R=ken2
CC=golang-dev
https://golang.org/cl/4003045
diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 88e0fc0..6711f69 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -56,6 +56,34 @@
typecheck(&l->n, top);
}
+static char* typekind[] = {
+ [TINT] = "int",
+ [TUINT] = "uint",
+ [TINT8] = "int8",
+ [TUINT8] = "uint8",
+ [TINT16] = "int16",
+ [TUINT16] = "uint16",
+ [TINT32] = "int32",
+ [TUINT32] = "uint32",
+ [TINT64] = "int64",
+ [TUINT64] = "uint64",
+ [TUINTPTR] = "uintptr",
+ [TCOMPLEX64] = "complex64",
+ [TCOMPLEX128] = "complex128",
+ [TFLOAT32] = "float32",
+ [TFLOAT64] = "float64",
+ [TBOOL] = "bool",
+ [TSTRING] = "string",
+ [TPTR32] = "pointer",
+ [TPTR64] = "pointer",
+ [TSTRUCT] = "struct",
+ [TINTER] = "interface",
+ [TCHAN] = "chan",
+ [TMAP] = "map",
+ [TARRAY] = "array",
+ [TFUNC] = "func",
+};
+
/*
* type check node *np.
* replaces *np with a new pointer in some cases.
@@ -372,21 +400,25 @@
et = t->etype;
}
if(t->etype != TIDEAL && !eqtype(l->type, r->type)) {
- badbinary:
defaultlit2(&l, &r, 1);
- yyerror("invalid operation: %#N (type %T %#O %T)", n, l->type, op, r->type);
+ yyerror("invalid operation: %#N (mismatched types %T and %T)", n, l->type, r->type);
goto error;
}
- if(!okfor[op][et])
- goto badbinary;
+ if(!okfor[op][et]) {
+ notokfor:
+ yyerror("invalid operation: %#N (operator %#O not defined on %s)", n, op, typekind[et]);
+ goto error;
+ }
// okfor allows any array == array;
// restrict to slice == nil and nil == slice.
if(l->type->etype == TARRAY && !isslice(l->type))
- goto badbinary;
+ goto notokfor;
if(r->type->etype == TARRAY && !isslice(r->type))
- goto badbinary;
- if(isslice(l->type) && !isnil(l) && !isnil(r))
- goto badbinary;
+ goto notokfor;
+ if(isslice(l->type) && !isnil(l) && !isnil(r)) {
+ yyerror("invalid operation: %#N (slice can only be compared to nil)", n);
+ goto error;
+ }
t = l->type;
if(iscmp[n->op]) {
evconst(n);
