From 1e6382c564629f8a3998800f0273a44c7cb84c14 Mon Sep 17 00:00:00 2001
From: "A. R. Shajii" <ars@ars.me>
Date: Tue, 3 Oct 2023 17:04:15 -0400
Subject: [PATCH] Fix domination within deeply nested blocks (#485)
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Co-authored-by: Ibrahim Numanagić <ibrahimpasa@gmail.com>
---
 codon/parser/visitors/simplify/ctx.cpp |  9 ++++++--
 test/parser/types.codon                | 32 ++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/codon/parser/visitors/simplify/ctx.cpp b/codon/parser/visitors/simplify/ctx.cpp
index 35b1112f..cecc53f8 100644
--- a/codon/parser/visitors/simplify/ctx.cpp
+++ b/codon/parser/visitors/simplify/ctx.cpp
@@ -126,11 +126,16 @@ SimplifyContext::Item SimplifyContext::findDominatingBinding(const std::string &
     // We went outside the function scope. Break.
     if (!isOutside && (*i)->getBaseName() != getBaseName())
       break;
+    bool completeDomination =
+        (*i)->scope.size() <= scope.blocks.size() &&
+        (*i)->scope.back() == scope.blocks[(*i)->scope.size() - 1];
+    if (!completeDomination && prefix < int(scope.blocks.size()) && prefix != p) {
+      break;
+    }
     prefix = p;
     lastGood = i;
     // The binding completely dominates the current scope. Break.
-    if ((*i)->scope.size() <= scope.blocks.size() &&
-        (*i)->scope.back() == scope.blocks[(*i)->scope.size() - 1])
+    if (completeDomination)
       break;
   }
   seqassert(lastGood != it->second.end(), "corrupted scoping ({})", name);
diff --git a/test/parser/types.codon b/test/parser/types.codon
index c90d0b04..3852deb1 100644
--- a/test/parser/types.codon
+++ b/test/parser/types.codon
@@ -1998,3 +1998,35 @@ print(Tuple[-5, int].__class__.__name__)
 #: Tuple
 print(Tuple[5, int, str].__class__.__name__)
 #: Tuple[int,str,int,str,int,str,int,str,int,str]
+
+
+#%% domination_nested,barebones
+def correlate(a, b, mode = 'valid'):
+    if mode == 'valid':
+        if isinstance(a, List):
+            xret = '1'
+        else:
+            xret = '2'
+        for i in a:
+            for j in b:
+                xret += 'z'
+    elif mode == 'same':
+        if isinstance(a, List):
+            xret = '3'
+        else:
+            xret = '4'
+        for i in a:
+            for j in b:
+                xret += 'z'
+    elif mode == 'full':
+        if isinstance(a, List):
+            xret = '5'
+        else:
+            xret = '6'
+        for i in a:
+            for j in b:
+                xret += 'z'
+    else:
+        raise ValueError(f"mode must be one of 'valid', 'same', or 'full' (got {repr(mode)})")
+    return xret
+print(correlate([1], [2], 'full'))  # 5z