From 3c35557872654d6c563725e2965dc2603819bcaf Mon Sep 17 00:00:00 2001
From: Jakub Doka <jakub.doka2@gmail.com>
Date: Mon, 11 Nov 2024 09:06:34 +0100
Subject: [PATCH] fixing type variables in loops

---
 lang/README.md                               | 20 +++++++++++
 lang/src/lib.rs                              |  5 ++-
 lang/src/son.rs                              | 19 +++++++++--
 lang/tests/son_tests_generic_type_mishap.txt | 35 ++++++++++++++++++++
 4 files changed, 75 insertions(+), 4 deletions(-)
 create mode 100644 lang/tests/son_tests_generic_type_mishap.txt

diff --git a/lang/README.md b/lang/README.md
index f5c97293..695d936c 100644
--- a/lang/README.md
+++ b/lang/README.md
@@ -615,6 +615,26 @@ main := fn(): uint {
 
 ### Purely Testing Examples
 
+#### generic_type_mishap
+```hb
+opaque := fn($Expr: type, ptr: ^?Expr): void {
+}
+
+process := fn($Expr: type): void {
+	optional := @as(?Expr, null)
+	timer := 1000
+	loop if timer > 0 {
+		opaque(Expr, &optional)
+		if optional != null return {
+		}
+		timer -= 1
+	}
+	return
+}
+
+main := fn(): void process(uint)
+```
+
 #### storing_into_nullable_struct
 ```hb
 StructA := struct {b: StructB, c: ^uint, d: uint}
diff --git a/lang/src/lib.rs b/lang/src/lib.rs
index 5a41744a..bd6120a1 100644
--- a/lang/src/lib.rs
+++ b/lang/src/lib.rs
@@ -1032,7 +1032,10 @@ trait TypeParser {
 
             let Some((expr @ Expr::BinOp { left, right, .. }, name)) = f.find_decl(id) else {
                 return match id {
-                    Ok(_) => ty::Id::NEVER,
+                    Ok(_) => {
+                        debug_assert_eq!(from_file, file);
+                        self.report(file, pos, "somehow this was not found")
+                    }
                     Err("main") => self.report(
                         from_file,
                         pos,
diff --git a/lang/src/son.rs b/lang/src/son.rs
index eb73dbed..c45179e7 100644
--- a/lang/src/son.rs
+++ b/lang/src/son.rs
@@ -2022,6 +2022,12 @@ struct Variable {
 
 impl Variable {
     fn new(id: Ident, ty: ty::Id, ptr: bool, value: Nid, nodes: &mut Nodes) -> Self {
+        if value == NEVER {
+            if ty == ty::Id::NEVER {
+                panic!();
+            }
+        }
+
         Self { id, ty, ptr, value: StrongRef::new(value, nodes) }
     }
 
@@ -3400,7 +3406,7 @@ impl<'a> Codegen<'a> {
                 });
 
                 for var in self.ci.scope.vars.iter_mut().skip(self.ci.inline_var_base) {
-                    if !var.ptr {
+                    if !var.ptr && var.value() != NEVER {
                         var.set_value(VOID, &mut self.ci.nodes);
                     }
                 }
@@ -4331,7 +4337,7 @@ impl<'a> Codegen<'a> {
             self.ci.nodes.basic_blocks();
             self.ci.nodes.graphviz(self.ty_display(ty::Id::VOID));
         } else {
-            self.ci.nodes.graphviz_in_browser(self.ty_display(ty::Id::VOID));
+            //self.ci.nodes.graphviz_in_browser(self.ty_display(ty::Id::VOID));
         }
 
         self.errors.borrow().len() == prev_err_len
@@ -4664,7 +4670,13 @@ impl TypeParser for Codegen<'_> {
     }
 
     fn find_local_ty(&mut self, ident: Ident) -> Option<ty::Id> {
-        self.ci.scope.vars.iter().rfind(|v| (v.id == ident && v.value() == NEVER)).map(|v| v.ty)
+        self.ci
+            .scope
+            .vars
+            .iter()
+            .rfind(|v| (v.id == ident && v.value() == NEVER))
+            .map(|v| v.ty)
+            .inspect(|&ty| debug_assert_ne!(ty, ty::Id::NEVER))
     }
 }
 
@@ -4743,6 +4755,7 @@ mod tests {
         fb_driver;
 
         // Purely Testing Examples;
+        generic_type_mishap;
         storing_into_nullable_struct;
         scheduling_block_did_dirty;
         null_check_returning_small_global;
diff --git a/lang/tests/son_tests_generic_type_mishap.txt b/lang/tests/son_tests_generic_type_mishap.txt
new file mode 100644
index 00000000..ab5bb18c
--- /dev/null
+++ b/lang/tests/son_tests_generic_type_mishap.txt
@@ -0,0 +1,35 @@
+main:
+    ADDI64 r254, r254, -8d
+    ST r31, r254, 0a, 8h
+    JAL r31, r0, :process
+    LD r31, r254, 0a, 8h
+    ADDI64 r254, r254, 8d
+    JALA r0, r31, 0a
+opaque:
+    JALA r0, r31, 0a
+process:
+    ADDI64 r254, r254, -64d
+    ST r31, r254, 16a, 48h
+    LI64 r32, 0d
+    LI64 r33, 1000d
+    ADDI64 r34, r254, 0d
+    LI8 r35, 0b
+    ST r35, r254, 0a, 1h
+ 4: JGTU r33, r32, :0
+    JMP :1
+ 0: CP r2, r34
+    JAL r31, r0, :opaque
+    LD r36, r254, 0a, 1h
+    ANDI r36, r36, 255d
+    ANDI r35, r35, 255d
+    JEQ r36, r35, :2
+    JMP :3
+ 2: ADDI64 r33, r33, -1d
+ 1: JMP :4
+ 3: LD r31, r254, 16a, 48h
+    ADDI64 r254, r254, 64d
+    JALA r0, r31, 0a
+timed out
+code size: 272
+ret: 0
+status: Ok(())