fixes a C code generator regression, no need to backport, only the 1.4 line is affected (#15569)

compiler/ccgcalls.nim

@@ -249,7 +249,7 @@ proc openArrayLoc(p: BProc, formalType: PType, n: PNode): Rope =
     else: internalError(p.config, "openArrayLoc: " & typeToString(a.t))
 
 proc withTmpIfNeeded(p: BProc, a: TLoc, needsTmp: bool): TLoc =
-  if needsTmp:
+  if needsTmp and a.lode.typ != nil:
     var tmp: TLoc
     getTemp(p, a.lode.typ, tmp, needsInit=false)
     genAssignment(p, tmp, a, {})

tests/ccgbugs/t2procs.nim

@@ -0,0 +1,18 @@
+discard """
+  output: '''before
+1
+before
+2'''
+"""
+
+proc fn[T1, T2](a: T1, b: T2) =
+  a(1)
+  b(2)
+
+fn( (proc(x: int) =
+      echo "before" # example block, can span multiple lines
+      echo x),
+    (proc (y: int) =
+      echo "before"
+      echo y)
+)