This method is called by the parser when a full-context prediction
results in an ambiguity.
<p>Each full-context prediction which does not result in a syntax error
will call either {@link #reportContextSensitivity} or
{@link #reportAmbiguity}.</p>
<p>When {@code ambigAlts} is not null, it contains the set of potentially
viable alternatives identified by the prediction algorithm. When
{@code ambigAlts} is null, use {@link ATNConfigSet#getAlts} to obtain the
represented alternatives from the {@code configs} argument.</p>
<p>When {@code exact} is {@code true}, <em>all</em> of the potentially
viable alternatives are truly viable, i.e. this is reporting an exact
ambiguity. When {@code exact} is {@code false}, <em>at least two</em> of
the potentially viable alternatives are viable for the current input, but
the prediction algorithm terminated as soon as it determined that at
least the <em>minimum</em> potentially viable alternative is truly
viable.</p>
<p>When the {@link PredictionMode#LL_EXACT_AMBIG_DETECTION} prediction
mode is used, the parser is required to identify exact ambiguities so
{@code exact} will always be {@code true}.</p>
<p>This method is not used by lexers.</p>
@param recognizer the parser instance
@param dfa the DFA for the current decision
@param startIndex the input index where the decision started
@param stopIndex the input input where the ambiguity was identified
@param exact {@code true} if the ambiguity is exactly known, otherwise
{@code false}. This is always {@code true} when
{@link PredictionMode#LL_EXACT_AMBIG_DETECTION} is used.
@param ambigAlts the potentially ambiguous alternatives, or {@code null}
to indicate that the potentially ambiguous alternatives are the complete
set of represented alternatives in {@code configs}
@param configs the ATN configuration set where the ambiguity was
identified
This method is called by the parser when a full-context prediction results in an ambiguity.
<p>Each full-context prediction which does not result in a syntax error will call either {@link #reportContextSensitivity} or {@link #reportAmbiguity}.</p>
<p>When {@code ambigAlts} is not null, it contains the set of potentially viable alternatives identified by the prediction algorithm. When {@code ambigAlts} is null, use {@link ATNConfigSet#getAlts} to obtain the represented alternatives from the {@code configs} argument.</p>
<p>When {@code exact} is {@code true}, <em>all</em> of the potentially viable alternatives are truly viable, i.e. this is reporting an exact ambiguity. When {@code exact} is {@code false}, <em>at least two</em> of the potentially viable alternatives are viable for the current input, but the prediction algorithm terminated as soon as it determined that at least the <em>minimum</em> potentially viable alternative is truly viable.</p>
<p>When the {@link PredictionMode#LL_EXACT_AMBIG_DETECTION} prediction mode is used, the parser is required to identify exact ambiguities so {@code exact} will always be {@code true}.</p>
<p>This method is not used by lexers.</p>
@param recognizer the parser instance @param dfa the DFA for the current decision @param startIndex the input index where the decision started @param stopIndex the input input where the ambiguity was identified @param exact {@code true} if the ambiguity is exactly known, otherwise {@code false}. This is always {@code true} when {@link PredictionMode#LL_EXACT_AMBIG_DETECTION} is used. @param ambigAlts the potentially ambiguous alternatives, or {@code null} to indicate that the potentially ambiguous alternatives are the complete set of represented alternatives in {@code configs} @param configs the ATN configuration set where the ambiguity was identified