Merge pull request #7981 from cooldome/Fix_-7980

Fixes 7980

compiler/patterns.nim

@@ -77,7 +77,7 @@ proc checkTypes(c: PPatternContext, p: PSym, n: PNode): bool =
   if isNil(n.typ):
     result = p.typ.kind in {tyVoid, tyStmt}
   else:
-    result = sigmatch.argtypeMatches(c.c, p.typ, n.typ)
+    result = sigmatch.argtypeMatches(c.c, p.typ, n.typ, fromHlo = true)
 
 proc isPatternParam(c: PPatternContext, p: PNode): bool {.inline.} =
   result = p.kind == nkSym and p.sym.kind == skParam and p.sym.owner == c.owner

compiler/sigmatch.nim

@@ -2366,14 +2366,18 @@ proc matches*(c: PContext, n, nOrig: PNode, m: var TCandidate) =
     for t in m.inferredTypes:
       if t.sonsLen > 1: t.sons.setLen 1
 
-proc argtypeMatches*(c: PContext, f, a: PType): bool =
+proc argtypeMatches*(c: PContext, f, a: PType, fromHlo = false): bool =
   var m: TCandidate
   initCandidate(c, m, f)
   let res = paramTypesMatch(m, f, a, c.graph.emptyNode, nil)
   #instantiateGenericConverters(c, res, m)
   # XXX this is used by patterns.nim too; I think it's better to not
   # instantiate generic converters for that
-  result = res != nil
+  if not fromHlo:
+    res != nil
+  else:
+    # pattern templates do not allow for conversions except from int literal
+    res != nil and m.convMatches == 0 and m.intConvMatches in [0, 256]
 
 proc instTypeBoundOp*(c: PContext; dc: PSym; t: PType; info: TLineInfo;
                       op: TTypeAttachedOp; col: int): PSym {.procvar.} =

tests/template/tpattern_with_converter.nim

@@ -0,0 +1,27 @@
+discard """
+  output: 10.0
+"""
+
+type
+  MyFloat = object
+    val: float
+
+converter to_myfloat*(x: float): MyFloat {.inline.} =
+  MyFloat(val: x)
+
+proc `+`(x1, x2: MyFloat): MyFloat =
+  MyFloat(val: x1.val + x2.val)
+
+proc `*`(x1, x2: MyFloat): MyFloat =
+    MyFloat(val: x1.val * x2.val)
+
+template optMul{`*`(a, 2.0)}(a: MyFloat): MyFloat =
+  a + a
+
+func floatMyFloat(x: MyFloat): MyFloat =
+  result = x * 2.0
+
+func floatDouble(x: float): float =
+  result = x * 2.0
+
+echo floatDouble(5)