fix #12864 static params were mutating arg types during sigmatch; fix #12713 ; refs #13529 (#13976)

* fix #12864 static params were mutating arg types during sigmatch

* fix test

* fix StaticParam

* also fixes #12713; added test case

compiler/sigmatch.nim

@@ -2004,6 +2004,7 @@ proc paramTypesMatchAux(m: var TCandidate, f, a: PType,
         let typ = newTypeS(tyStatic, c)
         typ.sons = @[evaluated.typ]
         typ.n = evaluated
+        arg = copyTree(arg) # fix #12864
         arg.typ = typ
         a = typ
       else:

lib/pure/typetraits.nim

@@ -93,7 +93,7 @@ since (1, 1):
     # Note: `[]` currently gives: `Error: no generic parameters allowed for ...`
     type(default(T)[i])
 
-  type StaticParam*[value] = object
+  type StaticParam*[value: static type] = object
     ## used to wrap a static value in `genericParams`
 
 # NOTE: See https://github.com/nim-lang/Nim/issues/13758 - `import std/macros` does not work on OpenBSD
@@ -118,13 +118,12 @@ macro genericParamsImpl(T: typedesc): untyped =
           let ai = impl[i]
           var ret: NimNode
           case ai.typeKind
-          of ntyStatic:
-            since (1, 1):
-              ret = newTree(nnkBracketExpr, @[bindSym"StaticParam", ai])
           of ntyTypeDesc:
             ret = ai
+          of ntyStatic: doAssert false
           else:
-            assert false, $(ai.typeKind, ai.kind)
+            since (1, 1):
+              ret = newTree(nnkBracketExpr, @[bindSym"StaticParam", ai])
           result.add ret
         break
       else:

tests/metatype/tstaticparams.nim

@@ -171,3 +171,27 @@ echo inSize([
   [1, 2, 3],
   [4, 5, 6]
 ])
+
+block: # #12864
+  template fun() =
+    type Object = object
+    proc fun(f: Object): int = 1
+    proc fun(f: static[int]): int = 2
+    doAssert fun(Object()) == 1
+
+    var a: Object
+    doAssert fun(a) == 1
+
+    proc fun2(f: Object): int = 1
+    proc fun2(f: static[Object]): int = 2
+    doAssert fun2(Object()) == 2
+    doAssert fun2(a) == 1
+    const a2 = Object()
+    doAssert fun2(a2) == 2
+
+  fun()
+  static: fun()
+
+when true: #12864 original snippet
+  import times
+  discard times.format(initDateTime(30, mMar, 2017, 0, 0, 0, 0, utc()), TimeFormat())

tests/metatype/ttypetraits.nim

@@ -145,6 +145,7 @@ block genericParams:
   doAssert genericParams(Bar3).get(0) is StaticParam
   doAssert genericParams(Bar3).get(0).value == 3
   doAssert genericParams(Bar[3, float]).get(0).value == 3
+  static: doAssert genericParams(Bar[3, float]).get(0).value == 3
 
   type
     VectorElementType = SomeNumber | bool

tests/statictypes/t9255.nim

@@ -1,6 +1,6 @@
 discard """
   errormsg: '''
-type mismatch: got <static[proc (a0: int): string{.noSideEffect, gcsafe, locks: 0.}](bar)>
+type mismatch: got <proc (a0: int): string{.noSideEffect, gcsafe, locks: 0.}>
 '''
   line: 13
 """

tests/statictypes/tstatictypes.nim

@@ -170,3 +170,49 @@ var
   s: StringValue16
 
 echo s
+
+block: #13529
+  block:
+    type Foo[T: static type] = object
+    var foo: Foo["test"]
+    doAssert $foo == "()"
+    doAssert foo.T is string
+    static: doAssert foo.T == "test"
+    doAssert not compiles(
+      block:
+        type Foo2[T: static type] = object
+          x: T)
+
+  block:
+    type Foo[T: static[float]] = object
+    var foo: Foo[1.2]
+    doAssert $foo == "()"
+    doAssert foo.T == 1.2
+
+  block: # routines also work
+    proc fun(a: static) = (const a2 = a)
+    fun(1)
+    fun(1.2)
+  block: # routines also work
+    proc fun(a: static type) = (const a2 = a)
+    fun(1)
+    fun(1.2)
+
+  block: # this also works
+    proc fun[T](a: static[T]) = (const a2 = a)
+    fun(1)
+    fun(1.2)
+
+block: # #12713
+  block:
+    type Cell = object
+      c: int
+    proc test(c: static string) = discard #Remove this and it compiles
+    proc test(c: Cell) = discard
+    test Cell(c: 0)
+  block:
+    type Cell = object
+      c: int
+    proc test(c: static string) = discard #Remove this and it compiles
+    proc test(c: Cell) = discard
+    test Cell()