diagnose various conversion problems

R=ken
OCL=17320
CL=17320

7 files changed, 78 insertions, 17 deletions

diff --git a/src/cmd/gc/const.c b/src/cmd/gc/const.c
index b624e2aba..9ee33ad11 100644
--- a/src/cmd/gc/const.c
+++ b/src/cmd/gc/const.c
@@ -8,7 +8,7 @@
 void
 convlit(Node *n, Type *t)
 {
-	int et;
+	int et, wt;
 
 	if(n == N || t == T)
 		return;
@@ -25,18 +25,10 @@ convlit(Node *n, Type *t)
 	}
 
 	et = t->etype;
-	switch(et) {
-	case TARRAY:
-	case TFUNC:
-	case TCHAN:
-	case TMAP:
-	case TSTRUCT:
-//	case TPTR32:
-//	case TPTR64:
-		return;
-	}
 
-	switch(whatis(n)) {
+	wt = whatis(n);
+
+	switch(wt) {
 	default:
 		goto bad1;
 
@@ -125,6 +117,8 @@ convlit(Node *n, Type *t)
 				goto bad2;
 			if(mpcmpfltfix(fv, maxintval[et]) > 0)
 				goto bad2;
+			if(floor(mpgetflt(fv)) != mpgetflt(fv))
+				goto bad3;
 			n->val.u.xval = mal(sizeof(*n->val.u.xval));
 			mpmovefltfix(n->val.u.xval, fv);
 			n->val.ctype = CTINT;
@@ -144,12 +138,16 @@ convlit(Node *n, Type *t)
 	return;
 
 bad1:
-	yyerror("illegal conversion of constant to %T", t);
+	yyerror("illegal conversion of %W to %T", wt, t);
 	return;
 
 bad2:
 	yyerror("overflow converting constant to %T", t);
 	return;
+
+bad3:
+	yyerror("cannot convert non-integer constant to %T", t);
+	return;
 }
 
 void
@@ -212,7 +210,7 @@ evconst(Node *n)
 			nl->val.ctype = CTFLT;
 			wl = whatis(nl);
 		} else {
-			yyerror("illegal combination of literals %E %E", nl->etype, nr->etype);
+			yyerror("illegal combination of literals %O %E, %E", n->op, wl, wr);
 			return;
 		}
 	}
@@ -230,7 +228,7 @@ evconst(Node *n)
 
 	switch(TUP(n->op, wl)) {
 	default:
-		yyerror("illegal combination of literals %O %E", n->op, nl->etype);
+		yyerror("illegal literal %O %E", n->op, wl);
 		return;
 
 	case TUP(OADD, Wlitint):
diff --git a/src/cmd/gc/dcl.c b/src/cmd/gc/dcl.c
index 725bfd2ae..6368fa4bd 100644
--- a/src/cmd/gc/dcl.c
+++ b/src/cmd/gc/dcl.c
@@ -27,6 +27,13 @@ dodclvar(Node *n, Type *t)
 		dodclvar(n->left, t);
 
 	dowidth(t);
+
+	// in case of type checking error,
+	// use "undefined" type for variable type,
+	// to avoid fatal in addvar.
+	if(t == T)
+		t = typ(TFORW);
+
 	addvar(n, t, dclcontext);
 	if(exportadj)
 		exportsym(n->sym);
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 92dc1260c..42b068c8d 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -598,6 +598,7 @@ Node*	syslook(char*, int);
 Node*	treecopy(Node*);
 int	isselect(Node*);
 void	tempname(Node*, Type*);
+int	iscomposite(Type*);
 
 Type**	getthis(Type*);
 Type**	getoutarg(Type*);
@@ -621,6 +622,7 @@ int	Oconv(Fmt*);
 int	Sconv(Fmt*);
 int	Tconv(Fmt*);
 int	Nconv(Fmt*);
+int	Wconv(Fmt*);
 int	Zconv(Fmt*);
 
 /*
diff --git a/src/cmd/gc/go.y b/src/cmd/gc/go.y
index 3e69c305e..4afc1c6e8 100644
--- a/src/cmd/gc/go.y
+++ b/src/cmd/gc/go.y
@@ -872,6 +872,8 @@ pexpr:
 	{
 		$$ = nod(OCONV, $3, N);
 		$$->type = oldtype($1);
+		if(iscomposite($$->type))
+			yyerror("illegal conversion type %T", $$->type);
 	}
 |	convtype '{' braced_keyexpr_list '}'
 	{
@@ -879,6 +881,8 @@ pexpr:
 		$$ = rev($3);
 		if($$ == N)
 			$$ = nod(OEMPTY, N, N);
+		if(!iscomposite($1))
+			yyerror("illegal composite literal type %T", $1);
 		$$ = nod(OCONV, $$, N);
 		$$->type = $1;
 	}
diff --git a/src/cmd/gc/lex.c b/src/cmd/gc/lex.c
index 41bc1c74b..d0bff2741 100644
--- a/src/cmd/gc/lex.c
+++ b/src/cmd/gc/lex.c
@@ -53,6 +53,7 @@ mainlex(int argc, char *argv[])
 	fmtinstall('Z', Zconv);		// escaped string
 	fmtinstall('L', Lconv);		// line number
 	fmtinstall('B', Bconv);		// big numbers
+	fmtinstall('W', Wconv);		// whatis numbers (Wlitint)
 
 	lexinit();
 	lineno = 1;
diff --git a/src/cmd/gc/subr.c b/src/cmd/gc/subr.c
index 76c585d67..c086aeb85 100644
--- a/src/cmd/gc/subr.c
+++ b/src/cmd/gc/subr.c
@@ -822,6 +822,8 @@ etnames[] =
 	[TSTRING]	= "STRING",
 	[TCHAN]		= "CHAN",
 	[TANY]		= "ANY",
+	[TFORWINTER]	= "FORWINTER",
+	[TFORWSTRUCT]	= "FORWSTRUCT",
 };
 
 int
@@ -1327,6 +1329,36 @@ out:
 	return fmtstrcpy(fp, buf);
 }
 
+
+static char*
+wnames[] =
+{
+	[Wnil] =	"Wnil",
+	[Wtnil] =	"Wtnil",
+
+	[Wtfloat] =	"Wtfloat",
+	[Wtint] =	"Wtint",
+	[Wtbool] =	"Wtbool",
+	[Wtstr] =	"Wtstr",
+
+	[Wlitfloat] =	"float constant",
+	[Wlitint] =	"int constant",
+	[Wlitbool] =	"bool",
+	[Wlitstr] =	"string",
+	[Wlitnil] =	"nil",
+};
+
+int
+Wconv(Fmt *fp)
+{
+	char buf[500];
+	int w;
+
+	w = va_arg(fp->args, int);
+	if(w < 0 || w >= nelem(wnames) || wnames[w] == nil)
+		return fmtprint(fp, "W-%d", w);
+	return fmtstrcpy(fp, wnames[w]);
+}
 int
 isnil(Node *n)
 {
@@ -1466,6 +1498,20 @@ out:
 	return t;
 }
 
+int
+iscomposite(Type *t)
+{
+	if(t == T)
+		return 0;
+	switch(t->etype) {
+	case TMAP:
+	case TARRAY:
+	case TSTRUCT:
+		return 1;
+	}
+	return 0;
+}
+
 Sym*
 globalsig(Type *t)
 {
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 761a723dc..610051a50 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -521,13 +521,15 @@ loop:
 		l = n->left;
 		if(l == N)
 			goto ret;
+
 		walktype(l, Erv);
 
 		t = n->type;
 		if(t == T)
 			goto ret;
 
-		convlit(l, t);
+		if(!iscomposite(t))
+			convlit(l, t);
 
 		// nil conversion
 		if(eqtype(t, l->type, 0)) {
@@ -589,7 +591,8 @@ loop:
 			goto ret;
 		}
 
-		badtype(n->op, l->type, t);
+		if(l->type != T)
+			yyerror("cannot convert %T to %T", l->type, t);
 		goto ret;
 
 	case ORETURN: