From 077e16888454e79469490c84f2fffeda65612bbd Mon Sep 17 00:00:00 2001
From: flywind <xzsflywind@gmail.com>
Date: Tue, 18 Jan 2022 20:01:43 +0800
Subject: [PATCH 1/3] fix term rewriting with sideeffect

fix #6217
---
 compiler/parampatterns.nim          | 7 +++++--
 tests/template/template_various.nim | 8 ++++++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/compiler/parampatterns.nim b/compiler/parampatterns.nim
index eb99004ab3c1..bfbc7267588f 100644
--- a/compiler/parampatterns.nim
+++ b/compiler/parampatterns.nim
@@ -143,8 +143,11 @@ proc checkForSideEffects*(n: PNode): TSideEffectAnalysis =
       let s = op.sym
       if sfSideEffect in s.flags:
         return seSideEffect
-      # assume no side effect:
-      result = seNoSideEffect
+      elif tfNoSideEffect in op.typ.flags:
+        result = seNoSideEffect
+      else:
+        # assume side effect:
+        result = seSideEffect
     elif tfNoSideEffect in op.typ.flags:
       # indirect call without side effects:
       result = seNoSideEffect
diff --git a/tests/template/template_various.nim b/tests/template/template_various.nim
index e7a2be748df7..2b900e27f531 100644
--- a/tests/template/template_various.nim
+++ b/tests/template/template_various.nim
@@ -145,8 +145,16 @@ block pattern_with_converter:
 
   doAssert floatDouble(5) == 10.0
 
+block pattern_with_sideeffect:
+  template optMul{`*`(a, 2)}(a: int{noSideEffect}): int = a+a
 
+  var i = 0
+  proc f(): int =
+    i += 1
+    result = 55
 
+  doAssert f() * 2 == 110
+  doAssert i == 1
 
 block procparshadow:
   template something(name: untyped) =

From ca5718d200e83211b4e4ead150dc4fe867a40a5c Mon Sep 17 00:00:00 2001
From: flywind <xzsflywind@gmail.com>
Date: Tue, 18 Jan 2022 20:08:13 +0800
Subject: [PATCH 2/3] add tests

---
 tests/template/t6217.nim            | 19 +++++++++++++++++++
 tests/template/template_various.nim | 11 -----------
 2 files changed, 19 insertions(+), 11 deletions(-)
 create mode 100644 tests/template/t6217.nim

diff --git a/tests/template/t6217.nim b/tests/template/t6217.nim
new file mode 100644
index 000000000000..b27b61881dea
--- /dev/null
+++ b/tests/template/t6217.nim
@@ -0,0 +1,19 @@
+discard """
+  output: '''
+start
+side effect!
+end
+'''
+"""
+
+# bug #6217
+
+template optMul{`*`(a, 2)}(a: int{noSideEffect}): int = a+a
+
+proc f(): int =
+  echo "side effect!"
+  result = 55
+
+echo "start"
+doAssert f() * 2 == 110
+echo "end"
diff --git a/tests/template/template_various.nim b/tests/template/template_various.nim
index 2b900e27f531..5b99eec9c86a 100644
--- a/tests/template/template_various.nim
+++ b/tests/template/template_various.nim
@@ -145,17 +145,6 @@ block pattern_with_converter:
 
   doAssert floatDouble(5) == 10.0
 
-block pattern_with_sideeffect:
-  template optMul{`*`(a, 2)}(a: int{noSideEffect}): int = a+a
-
-  var i = 0
-  proc f(): int =
-    i += 1
-    result = 55
-
-  doAssert f() * 2 == 110
-  doAssert i == 1
-
 block procparshadow:
   template something(name: untyped) =
     proc name(x: int) =

From ab12de4314d887a5aafd6787e6d5f55921230812 Mon Sep 17 00:00:00 2001
From: flywind <xzsflywind@gmail.com>
Date: Tue, 18 Jan 2022 20:10:23 +0800
Subject: [PATCH 3/3] Update tests/template/template_various.nim

---
 tests/template/template_various.nim | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tests/template/template_various.nim b/tests/template/template_various.nim
index 5b99eec9c86a..e7a2be748df7 100644
--- a/tests/template/template_various.nim
+++ b/tests/template/template_various.nim
@@ -145,6 +145,9 @@ block pattern_with_converter:
 
   doAssert floatDouble(5) == 10.0
 
+
+
+
 block procparshadow:
   template something(name: untyped) =
     proc name(x: int) =