[Bug-kawa] [bug #36863] then clause grows stack with no else clause

[Helmut Eller]

URL:
  <http://savannah.gnu.org/bugs/?36863>

                 Summary: then clause grows stack with no else clause
                 Project: Kawa
            Submitted by: ellerh
            Submitted on: Tue 17 Jul 2012 01:50:55 PM GMT
                Category: Code generation
                Severity: 3 - Normal
              Item Group: Compile-time exception
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any

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Details:

This example

(define (first (iterable java.lang.Iterable))
  (let ((f (lambda (x) #t))
        (iter (iterable:iterator)))
    (let loop ()
      (if (iter:hasNext)
          (let ((item (iter:next)))
            (if (f item)
                item
                (loop)))
          #f))))


causes this error:

shell> kawa --version -C x.scm 
Kawa 1.12.1 (revision 7274M)
Copyright (C) 2011 Per Bothner
(compiling x.scm to x)
x.scm:7: internal error while compiling x.scm
java.lang.Error: at PC 30 then clause grows stack with no else clause
        at gnu.bytecode.CodeAttr.emitFi(CodeAttr.java:1902)
        at gnu.expr.IfExp.compile(IfExp.java:138)
        at gnu.expr.IfExp.compile(IfExp.java:52)
        at gnu.expr.Expression.compileNotePosition(Expression.java:156)
        at gnu.expr.Expression.compileWithPosition(Expression.java:127)
        at gnu.expr.LetExp.compile(LetExp.java:193)
        at gnu.expr.Expression.compileNotePosition(Expression.java:156)
        at gnu.expr.Expression.compileWithPosition(Expression.java:127)
        at gnu.expr.IfExp.compile(IfExp.java:123)
        at gnu.expr.IfExp.compile(IfExp.java:52)
        at gnu.expr.Expression.compileNotePosition(Expression.java:156)
        at gnu.expr.Expression.compileWithPosition(Expression.java:127)
        at gnu.expr.ApplyExp.compile(ApplyExp.java:327)
        at gnu.expr.ApplyExp.compile(ApplyExp.java:126)
        at gnu.expr.Expression.compileNotePosition(Expression.java:156)
        at gnu.expr.Expression.compileWithPosition(Expression.java:127)
        at gnu.expr.BeginExp.compile(BeginExp.java:153)
        at gnu.expr.Expression.compileNotePosition(Expression.java:156)
        at gnu.expr.Expression.compileWithPosition(Expression.java:127)
        at gnu.expr.LetExp.compile(LetExp.java:193)
        at gnu.expr.Expression.compileNotePosition(Expression.java:156)
        at gnu.expr.Expression.compileWithPosition(Expression.java:127)
        at gnu.expr.LetExp.compile(LetExp.java:193)
        at gnu.expr.Expression.compileNotePosition(Expression.java:156)
        at gnu.expr.Expression.compileWithPosition(Expression.java:142)
        at gnu.expr.LambdaExp.compileBody(LambdaExp.java:1671)
        at gnu.expr.LambdaExp.compileAsMethod(LambdaExp.java:1647)
        at gnu.expr.LambdaExp.compileSetField(LambdaExp.java:689)
        at gnu.expr.SetExp.compile(SetExp.java:170)
        at gnu.expr.Expression.compileNotePosition(Expression.java:156)
        at gnu.expr.Expression.compileWithPosition(Expression.java:142)
        at gnu.expr.LambdaExp.compileBody(LambdaExp.java:1671)
        at gnu.expr.Compilation.generateBytecode(Compilation.java:2074)
        at gnu.expr.Compilation.process(Compilation.java:1952)
        at gnu.expr.ModuleInfo.loadByStages(ModuleInfo.java:305)
        at gnu.expr.ModuleInfo.loadByStages(ModuleInfo.java:290)
        at kawa.repl.compileFiles(repl.java:824)
        at kawa.repl.processArgs(repl.java:444)
        at kawa.repl.main(repl.java:870)






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