java/1426: Compiler fails to catch constructor problem
green@cygnus.com
green@cygnus.com
Wed Dec 20 12:26:00 GMT 2000
>Number: 1426
>Category: java
>Synopsis: Compiler fails to catch constructor problem
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: apbianco
>State: closed
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Wed Dec 20 12:19:43 PST 2000
>Closed-Date: Mon Nov 01 01:59:54 PST 1999
>Last-Modified: Mon Nov 1 02:00:00 PST 1999
>Originator: Anthony Green
>Release: 2.96 (trunk)
>Organization:
>Environment:
>Description:
The compiler fails to catch the use of `this' in a
constructor before calling the superclass constructor.
>How-To-Repeat:
The following patch corrects invalid
code in java/io/OutputStreamWriter.java.
Revert this patch. The compiler should issue an error.
Compiling it with javac produces:
./java/io/OutputStreamWriter.java:35: Can't reference this before the superclass constructor has been called.
super((this.out = (out instanceof BufferedOutputStream
Index: java/io/OutputStreamWriter.java
===================================================================
RCS file: /cvs/java/libgcj/libjava/java/io/OutputStreamWriter.java,v
retrieving revision 1.2
diff -u -r1.2 OutputStreamWriter.java
--- OutputStreamWriter.java 1999/04/16 18:35:01 1.2
+++ OutputStreamWriter.java 1999/09/21 19:44:32
@@ -32,9 +32,11 @@
private OutputStreamWriter(OutputStream out, UnicodeToBytes encoder)
{
- super((this.out = (out instanceof BufferedOutputStream
- ? (BufferedOutputStream) out
- : new BufferedOutputStream(out, 250))));
+ BufferedOutputStream buf = (out instanceof BufferedOutputStream
+ ? (BufferedOutputStream) out
+ : new BufferedOutputStream(out, 250));
+ super (buf);
+ this.out = buf;
this.converter = encoder;
}
>Fix:
>Release-Note:
>Audit-Trail:
Formerly PR gcj/48
From: Tom Tromey <tromey@cygnus.com>
To: Java Gnats Server <java-gnats@sourceware.cygnus.com>
Cc:
Subject: gcj/48
Date: 21 Sep 1999 15:53:52 -0600
Note that PR #50 refers to the java.io side of this problem.
The patch that was checked in was reverted due to incorrectness :-(.
Tom
State-Changed-From-To: open->feedback
State-Changed-By: apbianco
State-Changed-When: Fri Oct 29 08:51:27 1999
State-Changed-Why:
Patch send to the mailing list.
From: apbianco@cygnus.com
To: apbianco@cygnus.com, green@cygnus.com, java-gnats@sourceware.cygnus.com
Cc:
Subject: Re: gcj/48
Date: 29 Oct 1999 15:51:27 -0000
Synopsis: Compiler fails to catch constructor problem
State-Changed-From-To: open->feedback
State-Changed-By: apbianco
State-Changed-When: Fri Oct 29 08:51:27 1999
State-Changed-Why:
Patch send to the mailing list.
http://sourceware.cygnus.com/cgi-bin/gnatsweb.pl?cmd=view&database=java&pr=48
From: Alexandre Petit-Bianco <apbianco@cygnus.com>
To: green@cygnus.com
Cc: java-gnats@sourceware.cygnus.com
Subject: Re: gcj/48: Compiler fails to catch constructor problem
Date: Fri, 29 Oct 1999 08:51:34 -0700 (PDT)
green@cygnus.com writes:
> The compiler fails to catch the use of `this' in a
> constructor before calling the superclass constructor.
I have a patch for that, see below. With that patch, I get several
failures compiling libjava:
--
java/io/InputStreamReader.java:47: Can't reference `this' before the superclass constructor has been called.
super((this.in = (in instanceof BufferedInputStream
^
1 error
java/io/OutputStreamWriter.java:35: Can't reference `this' before the superclass constructor has been called.
super((this.out = (out instanceof BufferedOutputStream
^
1 error
java/io/PrintStream.java:241: Can't reference `this' before the superclass constructor has been called.
super ((this.out = (out instanceof BufferedOutputStream
^
1 error
--
If someone can confirm these errors, I'll update PR #50 with the
mention of `InputStreamReader'.
./A
Index: parse.y
===================================================================
RCS file: /cvs/gcc/egcs/gcc/java/parse.y,v
retrieving revision 1.114
diff -u -p -r1.114 parse.y
--- parse.y 1999/10/22 06:06:47 1.114
+++ parse.y 1999/10/29 15:29:12
@@ -6716,6 +6716,12 @@ resolve_qualified_expression_name (wfl,
(wfl, "Keyword `this' used outside allowed context");
return 1;
}
+ if (ctxp->explicit_constructor_p)
+ {
+ parse_error_context (wfl, "Can't reference `this' before the "
+ "superclass constructor has been called");
+ return 1;
+ }
/* We have to generate code for intermediate acess */
*where_found = decl = current_this;
*type_found = type = QUAL_DECL_TYPE (decl);
@@ -8723,7 +8729,7 @@ complete_function_arguments (node)
int flag = 0;
tree cn;
- ctxp->explicit_constructor_p += (CALL_THIS_CONSTRUCTOR_P (node) ? 1 : 0);
+ ctxp->explicit_constructor_p += (CALL_EXPLICIT_CONSTRUCTOR_P (node) ? 1 : 0);
for (cn = TREE_OPERAND (node, 1); cn; cn = TREE_CHAIN (cn))
{
tree wfl = TREE_VALUE (cn), parm, temp;
@@ -8743,7 +8749,7 @@ complete_function_arguments (node)
TREE_VALUE (cn) = parm;
}
- ctxp->explicit_constructor_p -= (CALL_THIS_CONSTRUCTOR_P (node) ? 1 : 0);
+ ctxp->explicit_constructor_p -= (CALL_EXPLICIT_CONSTRUCTOR_P (node) ? 1 : 0);
return flag;
}
State-Changed-From-To: feedback->closed
State-Changed-By: apbianco
State-Changed-When: Mon Nov 1 01:59:54 1999
State-Changed-Why:
I checked in this patch:
http://egcs.cygnus.com/ml/gcc-patches/1999-11/msg00004.html
From: apbianco@cygnus.com
To: apbianco@cygnus.com, green@cygnus.com, java-gnats@sourceware.cygnus.com
Cc:
Subject: Re: gcj/48
Date: 1 Nov 1999 09:59:54 -0000
Synopsis: Compiler fails to catch constructor problem
State-Changed-From-To: feedback->closed
State-Changed-By: apbianco
State-Changed-When: Mon Nov 1 01:59:54 1999
State-Changed-Why:
I checked in this patch:
http://egcs.cygnus.com/ml/gcc-patches/1999-11/msg00004.html
http://sourceware.cygnus.com/cgi-bin/gnatsweb.pl?cmd=view&database=java&pr=48
>Unformatted:
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