Check if all segment exist right after parsing

src/main/scala/millfork/Main.scala

@@ -217,6 +217,8 @@ object Main {
       OptimizationPresets.NodeOpt0.foldLeft(unoptimized)((p, opt) => p.applyNodeOptimization(opt, options))
     }
     val callGraph = new StandardCallGraph(program, options.log)
+    program.checkSegments(options.log, platform.codeAllocators.keySet)
+    options.log.assertNoErrors("Build failed due to undefined segments")
 
     val env = new Environment(None, "", platform.cpuFamily, options)
     env.collectDeclarations(program, options)

src/main/scala/millfork/node/Program.scala

@@ -1,6 +1,7 @@
 package millfork.node
 
 import millfork.CompilationOptions
+import millfork.error.Logger
 import millfork.node.opt.NodeOptimization
 
 /**
@@ -18,6 +19,17 @@ case class Program(declarations: List[DeclarationStatement]) {
     })
   }
 
+  def checkSegments(log: Logger, existingBanks: Set[String]): Unit = {
+    declarations.foreach {
+      case s: BankedDeclarationStatement =>
+        s.bank.foreach{ b =>
+          if (!existingBanks(b)) {
+            log.error(s"Cannot allocate ${s.name}: Segment $b doesn't exist")
+          }
+        }
+      case _ =>
+    }
+  }
   def applyNodeOptimization(o: NodeOptimization, options: CompilationOptions) = Program(o.optimize(declarations, options).asInstanceOf[List[DeclarationStatement]])
   def +(p:Program): Program = Program(this.declarations ++ p.declarations)
 }

src/test/scala/millfork/test/emu/EmuRun.scala

@@ -184,6 +184,8 @@ class EmuRun(cpu: millfork.Cpu.Value, nodeOptimizations: List[NodeOptimization],
           tmp
         }
         val program = nodeOptimizations.foldLeft(withLibraries.applyImportantAliases)((p, opt) => p.applyNodeOptimization(opt, options))
+        program.checkSegments(log, platform.codeAllocators.keySet)
+        log.assertNoErrors("Failed")
         val callGraph = new StandardCallGraph(program, log)
         val env = new Environment(None, "", CpuFamily.M6502, options)
         env.collectDeclarations(program, options)

src/test/scala/millfork/test/emu/EmuZ80Run.scala

@@ -111,6 +111,8 @@ class EmuZ80Run(cpu: millfork.Cpu.Value, nodeOptimizations: List[NodeOptimizatio
           tmp
         }
         val program = nodeOptimizations.foldLeft(withLibraries.applyImportantAliases)((p, opt) => p.applyNodeOptimization(opt, options))
+        program.checkSegments(log, platform.codeAllocators.keySet)
+        log.assertNoErrors("Failed")
         val callGraph = new StandardCallGraph(program, log)
         val env = new Environment(None, "", CpuFamily.I80, options)
         env.collectDeclarations(program, options)