fixes #19603; some pragmas were really only supported as top level statements. Now this is enforced properly. (#19646)

(cherry picked from commit 51df9ff1c7)

compiler/pragmas.nim

@@ -44,18 +44,21 @@ const
     wDiscardable, wGensym, wInject, wRaises, wEffectsOf,
     wTags, wLocks, wGcSafe, wRequires, wEnsures}
   exprPragmas* = {wLine, wLocks, wNoRewrite, wGcSafe, wNoSideEffect}
-  stmtPragmas* = {wChecks, wObjChecks, wFieldChecks, wRangeChecks,
-    wBoundChecks, wOverflowChecks, wNilChecks, wStaticBoundchecks,
-    wStyleChecks, wAssertions,
-    wWarnings, wHints,
-    wLineDir, wStackTrace, wLineTrace, wOptimization, wHint, wWarning, wError,
+  stmtPragmas* = {
+    wHint, wWarning, wError,
     wFatal, wDefine, wUndef, wCompile, wLink, wLinksys, wPure, wPush, wPop,
     wPassl, wPassc, wLocalPassc,
     wDeadCodeElimUnused,  # deprecated, always on
     wDeprecated,
-    wFloatChecks, wInfChecks, wNanChecks, wPragma, wEmit, wUnroll,
+    wPragma, wEmit, wUnroll,
     wLinearScanEnd, wPatterns, wTrMacros, wEffects, wNoForward, wReorder, wComputedGoto,
     wExperimental, wThis, wUsed, wInvariant, wAssume, wAssert}
+  stmtPragmasTopLevel* = {wChecks, wObjChecks, wFieldChecks, wRangeChecks,
+    wBoundChecks, wOverflowChecks, wNilChecks, wStaticBoundchecks,
+    wStyleChecks, wAssertions,
+    wWarnings, wHints,
+    wLineDir, wStackTrace, wLineTrace, wOptimization,
+    wFloatChecks, wInfChecks, wNanChecks}
   lambdaPragmas* = {FirstCallConv..LastCallConv,
     wNoSideEffect, wSideEffect, wNoreturn, wNosinks, wDynlib, wHeader,
     wThread, wAsmNoStackFrame,

compiler/semexprs.nim

@@ -2786,6 +2786,12 @@ proc enumFieldSymChoice(c: PContext, n: PNode, s: PSym): PNode =
         onUse(info, a)
       a = nextOverloadIter(o, c, n)
 
+proc semPragmaStmt(c: PContext; n: PNode) =
+  if c.p.owner.kind == skModule:
+    pragma(c, c.p.owner, n, stmtPragmas+stmtPragmasTopLevel, true)
+  else:
+    pragma(c, c.p.owner, n, stmtPragmas, true)
+
 proc semExpr(c: PContext, n: PNode, flags: TExprFlags = {}): PNode =
   when defined(nimCompilerStacktraceHints):
     setFrameMsg c.config$n.info & " " & $n.kind
@@ -3047,7 +3053,7 @@ proc semExpr(c: PContext, n: PNode, flags: TExprFlags = {}): PNode =
   of nkUsingStmt: result = semUsing(c, n)
   of nkAsmStmt: result = semAsm(c, n)
   of nkYieldStmt: result = semYield(c, n)
-  of nkPragma: pragma(c, c.p.owner, n, stmtPragmas, true)
+  of nkPragma: semPragmaStmt(c, n)
   of nkIteratorDef: result = semIterator(c, n)
   of nkProcDef: result = semProc(c, n)
   of nkFuncDef: result = semFunc(c, n)