fixes 7980

compiler/hlo.nim

@@ -36,27 +36,35 @@ proc applyPatterns(c: PContext, n: PNode): PNode =
   # we apply the last pattern first, so that pattern overriding is possible;
   # however the resulting AST would better not trigger the old rule then
   # anymore ;-)
-  for i in countdown(c.patterns.len-1, 0):
-    let pattern = c.patterns[i]
-    if not isNil(pattern):
-      let x = applyRule(c, pattern, result)
-      if not isNil(x):
-        assert x.kind in {nkStmtList, nkCall}
-        # better be safe than sorry, so check evalTemplateCounter too:
-        inc(evalTemplateCounter)
-        if evalTemplateCounter > evalTemplateLimit:
-          globalError(c.config, n.info, "template instantiation too nested")
-        # deactivate this pattern:
-        c.patterns[i] = nil
-        if x.kind == nkStmtList:
-          assert x.len == 3
-          x.sons[1] = evalPattern(c, x.sons[1], result)
-          result = flattenStmts(x)
-        else:
-          result = evalPattern(c, x, result)
-        dec(evalTemplateCounter)
-        # activate this pattern again:
-        c.patterns[i] = pattern
+  if c.patterns.len > 0:
+
+    # temporary disable converters
+    var ctx_converters: TSymSeq
+    shallowCopy(ctx_converters, c.converters)
+    c.converters = @[]
+    defer: shallowCopy(c.converters, ctx_converters)
+
+    for i in countdown(c.patterns.len-1, 0):
+      let pattern = c.patterns[i]
+      if not isNil(pattern):
+        let x = applyRule(c, pattern, result)
+        if not isNil(x):
+          assert x.kind in {nkStmtList, nkCall}
+          # better be safe than sorry, so check evalTemplateCounter too:
+          inc(evalTemplateCounter)
+          if evalTemplateCounter > evalTemplateLimit:
+            globalError(c.config, n.info, "template instantiation too nested")
+          # deactivate this pattern:
+          c.patterns[i] = nil
+          if x.kind == nkStmtList:
+            assert x.len == 3
+            x.sons[1] = evalPattern(c, x.sons[1], result)
+            result = flattenStmts(x)
+          else:
+            result = evalPattern(c, x, result)
+          dec(evalTemplateCounter)
+          # activate this pattern again:
+          c.patterns[i] = pattern
 
 proc hlo(c: PContext, n: PNode): PNode =
   inc(c.hloLoopDetector)