JavaScript: Add support for parsing postfix generator comprehensions.

Max Schaefer · Max Schaefer · commit d3ae2954ff75 · 2019-02-24T20:45:41.000Z
diff --git a/javascript/extractor/src/com/semmle/jcorn/CustomParser.java b/javascript/extractor/src/com/semmle/jcorn/CustomParser.java
@@ -314,7 +314,29 @@ protected Expression parseParenAndDistinguishExpression(boolean canBeArrow) {
 			}
 		}
 
-		return super.parseParenAndDistinguishExpression(canBeArrow);
+		Expression res = super.parseParenAndDistinguishExpression(canBeArrow);
+		if (res instanceof ParenthesizedExpression) {
+			ParenthesizedExpression p = (ParenthesizedExpression) res;
+			if (p.getExpression() instanceof ComprehensionExpression) {
+				ComprehensionExpression c = (ComprehensionExpression) p.getExpression();
+				if (c.isGenerator())
+					return new ComprehensionExpression(p.getLoc(), c.getBody(), c.getBlocks(), c.getFilter(), c.isGenerator());
+			}
+		}
+		return res;
+	}
+
+	@Override
+	protected boolean parseParenthesisedExpression(DestructuringErrors refDestructuringErrors,
+			boolean allowTrailingComma, ParenthesisedExpressions parenExprs, boolean first) {
+		boolean cont = super.parseParenthesisedExpression(refDestructuringErrors, allowTrailingComma, parenExprs, first);
+		if (options.mozExtensions() && parenExprs.exprList.size() == 1 && this.type == TokenType._for) {
+			Expression body = parenExprs.exprList.remove(0);
+			ComprehensionExpression c = parseComprehension(body.getLoc().getStart(), true, body);
+			parenExprs.exprList.add(this.finishNode(c));
+			return false;
+		}
+		return cont;
 	}
 
 	// add parsing of for-each loops
diff --git a/javascript/extractor/tests/mozilla/input/generator_expressions.js b/javascript/extractor/tests/mozilla/input/generator_expressions.js
@@ -1,4 +1,5 @@
 (for (year of years) if (year > 2000) year);
 year;
 (for (i of numbers) for (j of letters) i+j);
-(for (i of numbers) for (j of letters) if (i<j) i+j);
+(for (i of numbers) for (j of letters) if (i<j) i+j);
+(x.p for (x in xs));
diff --git a/javascript/extractor/tests/mozilla/output/trap/generator_expressions.js.trap b/javascript/extractor/tests/mozilla/output/trap/generator_expressions.js.trap
