From 1b1f39eb862187b4e3a69679cf9746ad42546e9b Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Thu, 7 Jan 2010 23:24:48 -0800
Subject: [PATCH] gc: bug219, bug239, bug240

Fixes #475.

R=ken2
CC=golang-dev
https://golang.org/cl/183157
---
 src/cmd/gc/lex.c                   | 28 ++++++++++++++++++++++------
 test/{bugs => fixedbugs}/bug219.go |  3 +++
 test/{bugs => fixedbugs}/bug239.go |  0
 test/{bugs => fixedbugs}/bug240.go |  2 +-
 4 files changed, 26 insertions(+), 7 deletions(-)
 rename test/{bugs => fixedbugs}/bug219.go (94%)
 rename test/{bugs => fixedbugs}/bug239.go (100%)
 rename test/{bugs => fixedbugs}/bug240.go (91%)

diff --git a/src/cmd/gc/lex.c b/src/cmd/gc/lex.c
index 43b676d6fcc..75d6d2200a2 100644
--- a/src/cmd/gc/lex.c
+++ b/src/cmd/gc/lex.c
@@ -358,7 +358,6 @@ cannedimports(char *file, char *cp)
 	curio.cp = cp;
 	curio.nlsemi = 0;
 
-	pkgmyname = S;
 	typecheckok = 1;
 	incannedimport = 1;
 }
@@ -379,6 +378,12 @@ isfrog(int c)
 	return 0;
 }
 
+typedef struct Loophack Loophack;
+struct Loophack {
+	int v;
+	Loophack *next;
+};
+
 static int32
 _yylex(void)
 {
@@ -387,6 +392,8 @@ _yylex(void)
 	char *cp;
 	Rune rune;
 	Sym *s;
+	static Loophack *lstk;
+	Loophack *h;
 
 	prevlineno = lineno;
 
@@ -718,18 +725,27 @@ l0:
 	 * non-parenthesized '{' becomes an LBODY.
 	 * loophack is normally 0.
 	 * a keyword makes it go up to 1.
-	 * parens increment and decrement when loophack > 0.
+	 * parens push loophack onto a stack and go back to 0.
 	 * a '{' with loophack == 1 becomes LBODY and disables loophack.
 	 *
 	 * i said it was clumsy.
 	 */
 	case '(':
-		if(loophack > 0)
-			loophack++;
+		if(loophack || lstk != nil) {
+			h = malloc(sizeof *h);
+			h->v = loophack;
+			h->next = lstk;
+			lstk = h;
+			loophack = 0;
+		}
 		goto lx;
 	case ')':
-		if(loophack > 0)
-			loophack--;
+		if(lstk != nil) {
+			h = lstk;
+			loophack = h->v;
+			lstk = h->next;
+			free(h);
+		}
 		goto lx;
 	case '{':
 		if(loophack == 1) {
diff --git a/test/bugs/bug219.go b/test/fixedbugs/bug219.go
similarity index 94%
rename from test/bugs/bug219.go
rename to test/fixedbugs/bug219.go
index aee07cce7e0..21361a2aab3 100644
--- a/test/bugs/bug219.go
+++ b/test/fixedbugs/bug219.go
@@ -14,6 +14,7 @@ func g1() {
 	if x := f(func() {
 		if {}
 	}); {
+		_ = x;
 	}
 }
 
@@ -22,6 +23,7 @@ func g2() {
 	if x := f(func() {
 		//if {}
 	}); {
+		_ = x;
 	}
 }
 
@@ -31,5 +33,6 @@ func g3() {
 		if {}
 	});
 	if {
+		_ = x;
 	}
 }
diff --git a/test/bugs/bug239.go b/test/fixedbugs/bug239.go
similarity index 100%
rename from test/bugs/bug239.go
rename to test/fixedbugs/bug239.go
diff --git a/test/bugs/bug240.go b/test/fixedbugs/bug240.go
similarity index 91%
rename from test/bugs/bug240.go
rename to test/fixedbugs/bug240.go
index dc7cdd8963a..6cba9c8b1e5 100644
--- a/test/bugs/bug240.go
+++ b/test/fixedbugs/bug240.go
@@ -6,7 +6,7 @@
 
 package main
 
-import . "unsafe"
+import . "unsafe"	// ERROR "not used"
 
 func main() {
 	var x int