don't warn/error symbols in semGenericStmt/templates (#24907)

fixes #24905
fixes #24903
fixes https://github.com/nim-lang/Nim/issues/11805
fixes https://github.com/nim-lang/Nim/issues/15650

In the first phase of generic checking, we cannot warn/error symbols
because they can belong a false branch of `when` or there is a
`push/pop` options using open symbols. So we cannot decide whether to
warn/error or not

(cherry picked from commit 0506d5b973)

compiler/semexprs.nim

@@ -113,6 +113,8 @@ proc semExprNoDeref(c: PContext, n: PNode, flags: TExprFlags = {}): PNode =
 
 proc semSymGenericInstantiation(c: PContext, n: PNode, s: PSym): PNode =
   result = symChoice(c, n, s, scClosed)
+  if result.kind == nkSym:
+    markUsed(c, n.info, s)
 
 proc semSym(c: PContext, n: PNode, sym: PSym, flags: TExprFlags): PNode
 
@@ -3288,6 +3290,7 @@ proc semExpr(c: PContext, n: PNode, flags: TExprFlags = {}, expectedType: PType
       #performProcvarCheck(c, n, s)
       result = symChoice(c, n, s, scClosed)
       if result.kind == nkSym:
+        markUsed(c, n.info, s)
         markIndirect(c, result.sym)
         # if isGenericRoutine(result.sym):
         #   localError(c.config, n.info, errInstantiateXExplicitly, s.name.s)

compiler/semgnrc.nim

@@ -274,7 +274,8 @@ proc semGenericStmt(c: PContext, n: PNode,
     result = lookup(c, n, flags, ctx)
     if result != nil and result.kind == nkSym:
       assert result.sym != nil
-      markUsed(c, n.info, result.sym)
+      incl result.sym.flags, sfUsed
+      markOwnerModuleAsUsed(c, result.sym)
   of nkDotExpr:
     #let luf = if withinMixin notin flags: {checkUndeclared} else: {}
     #var s = qualifiedLookUp(c, n, luf)

compiler/semtempl.nim

@@ -67,12 +67,9 @@ proc symChoice(c: PContext, n: PNode, s: PSym, r: TSymChoiceRule;
     # for instance 'nextTry' is both in tables.nim and astalgo.nim ...
     if not isField or sfGenSym notin s.flags:
       result = newSymNode(s, info)
-      if isField:
-        # possibly not final field sym
-        incl(s.flags, sfUsed)
-        markOwnerModuleAsUsed(c, s)
-      else:
-        markUsed(c, info, s)
+      # possibly not final field sym
+      incl(s.flags, sfUsed)
+      markOwnerModuleAsUsed(c, s)
       onUse(info, s)
     else:
       result = n

nimsuggest/tests/tqualified_highlight.nim

@@ -6,9 +6,6 @@ discard """
 $nimsuggest --tester $file
 >highlight $1
 highlight;;skProc;;1;;7;;4
-highlight;;skProc;;1;;7;;4
-highlight;;skTemplate;;2;;7;;4
-highlight;;skTemplate;;2;;7;;4
 highlight;;skTemplate;;2;;7;;4
 highlight;;skFunc;;3;;8;;1
 """

tests/generics/toptions.nim

@@ -0,0 +1,39 @@
+discard """
+  matrix: "--warningAsError:Deprecated"
+"""
+
+block: # bug #24905
+  proc y() {.deprecated.} = discard
+  proc v(_: int | int) =
+    {.push warning[Deprecated]: off.}
+    y()
+    {.pop.}
+
+  v(1)
+
+block: # bug #24903
+  block:
+    proc y() {.deprecated.} = discard
+    proc m(_: int | int) =
+      when false: y()
+
+  block:
+    proc y() {.error.} = discard
+    proc m(_: int | int) =
+      when false: y()
+
+  block:
+    proc y() {.error.} = discard
+    proc m(_: int | int) =
+      when true: y()
+
+block: # bug #15650
+  proc bar() {.deprecated.} = discard
+
+  template foo() =
+    when false:
+      bar()
+    else:
+      discard
+
+  foo()