fixes unnamed block generated invalid C code

src/nimony/sem.nim

@@ -1206,8 +1206,11 @@ proc semWhile(c: var SemContext; it: var Item) =
   takeToken c, it.n
   semBoolExpr c, it.n
   inc c.routine.inLoop
+  let oldBreakInLoop = c.routine.breakInLoop
+  c.routine.breakInLoop = true
   withNewScope c:
     semStmt c, it.n, true
+  c.routine.breakInLoop = oldBreakInLoop
   dec c.routine.inLoop
   takeParRi c, it.n
   producesVoid c, info, it.typ
@@ -1217,6 +1220,8 @@ proc semBlock(c: var SemContext; it: var Item) =
   takeToken c, it.n
 
   inc c.routine.inBlock
+  let oldBreakInLoop = c.routine.breakInLoop
+  c.routine.breakInLoop = false
   withNewScope c:
     if it.n.kind == DotToken:
       takeToken c, it.n
@@ -1227,6 +1232,7 @@ proc semBlock(c: var SemContext; it: var Item) =
       publish c, delayed.s.name, declStart
 
     semStmtBranch c, it, true
+  c.routine.breakInLoop = oldBreakInLoop
   dec c.routine.inBlock
 
   takeParRi c, it.n
@@ -1242,6 +1248,8 @@ proc semBreak(c: var SemContext; it: var Item) =
   else:
     if it.n.kind == DotToken:
       wantDot c, it.n
+      if not c.routine.breakInLoop:
+        buildErr c, info, "Using an unnamed break in a block is not allowed"
     else:
       let labelInfo = it.n.info
       var a = Item(n: it.n, typ: c.types.autoType)
@@ -2600,7 +2608,10 @@ proc semFor(c: var SemContext; it: var Item) =
       takeTree c.dest, it.n # don't touch the body
     else:
       inc c.routine.inLoop
+      let oldBreakInLoop = c.routine.breakInLoop
+      c.routine.breakInLoop = true
       semStmt c, it.n, true
+      c.routine.breakInLoop = oldBreakInLoop
       dec c.routine.inLoop
 
   takeParRi c, it.n

src/nimony/semdata.nim

@@ -9,7 +9,7 @@
 import std / [tables, sets, os, syncio, formatfloat, assertions]
 include ".." / lib / nifprelude
 import ".." / lib / [symparser, nifindexes]
 import nimony_model, symtabs, builtintypes, decls, programs, magics, reporters, nifconfig, xints
 
 import ".." / gear2 / modnames
 
@@ -19,6 +19,7 @@
     kind*: SymKind
     hasDefer*: bool
     inGeneric*, inLoop*, inBlock*, inInst*: int
+    breakInLoop*: bool        # whether we are in a loop without block
     returnType*: TypeCursor
     pragmas*: set[PragmaKind]
     resId*: SymId

src/nimony/semdecls.nim

@@ -550,6 +550,7 @@ proc semProcImpl(c: var SemContext; it: var Item; kind: SymKind; pass: PassKind;
   if kind == TemplateY:
     inc c.routine.inLoop
     inc c.routine.inGeneric
+    c.routine.breakInLoop = true
 
   try:
     c.openScope() # open parameter scope

tests/nimony/nosystem/t1.nim

@@ -71,9 +71,9 @@ proc foo_block* =
     var s = 12
     break lab
 
-  block:
-    var s = 13
-    break
+  # block:
+  #   var s = 13
+  #   break
 
   block lab:
     var s = 14

tests/nimony/sysbasics/tblocks.nim

@@ -8,9 +8,9 @@ proc foo =
 foo()
 
 proc main =
-  block endLess:
-    let s = 12
-    break
+  # block endLess:
+  #   let s = 12
+  #   break
 
   block endLess:
     let s = 12
@@ -37,3 +37,21 @@ proc test(): int {.discardable.} =
 
 block:
   test()
+
+
+for i in 1..2: # works
+  break
+
+block: # works
+  for i in 1..2:
+    break
+
+block: # works
+  block:
+    discard 12 + 3
+  for i in 1..2:
+    break
+
+block named: # works
+  if true:
+    break named

tests/nimony/sysbasics/tunnamedblock.msgs

@@ -0,0 +1,2 @@
+tests/nimony/sysbasics/tunnamedblock.nim(2, 3) Error: Using an unnamed break in a block is not allowed
+tests/nimony/sysbasics/tunnamedblock.nim(6, 5) Error: Using an unnamed break in a block is not allowed

tests/nimony/sysbasics/tunnamedblock.nim

@@ -0,0 +1,6 @@
+block: # errors
+  break
+
+for i in 1..2: # errors
+  block:
+    break