Fix use of custom pragmas in generic procs (#8165)

Fixes #7626

compiler/semgnrc.nim

@@ -54,7 +54,8 @@ template macroToExpand(s): untyped =
   s.kind in {skMacro, skTemplate} and (s.typ.len == 1 or sfAllUntyped in s.flags)
 
 template macroToExpandSym(s): untyped =
-  s.kind in {skMacro, skTemplate} and (s.typ.len == 1) and not fromDotExpr
+  sfCustomPragma notin s.flags and s.kind in {skMacro, skTemplate} and
+    (s.typ.len == 1) and not fromDotExpr
 
 template isMixedIn(sym): bool =
   let s = sym

tests/pragmas/tcustom_pragma.nim

@@ -137,4 +137,12 @@ block:
   static:
     assert hasIntSerKey
     assert strSerKey == "string"
-    assert nestedItemDefVal == "Nimmers of the world, unite!"
+    assert nestedItemDefVal == "Nimmers of the world, unite!"
+
+block:
+  template simpleAttr {.pragma.}
+
+  type Annotated {.simpleAttr.} = object
+
+  proc generic_proc[T]() =
+    assert Annotated.hasCustomPragma(simpleAttr)