From 933913f816ea34d10a3c2904c46c7e59498f00fa Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sat, 2 Mar 2024 14:18:26 +0000
Subject: Convert to imperative loop

---
 .../compiler/typechecker/TypeCheckerSubTyping.java | 24 +++++++++-------------
 1 file changed, 10 insertions(+), 14 deletions(-)

(limited to 'src/main/java')

diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerSubTyping.java b/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerSubTyping.java
index 90f3db71..0456317c 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerSubTyping.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerSubTyping.java
@@ -9,9 +9,7 @@ import org.shedlang.compiler.types.*;
 import org.shedlang.compiler.util.P;
 import org.shedlang.compiler.util.PCollectors;
 
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
+import java.util.*;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
@@ -81,20 +79,19 @@ public class TypeCheckerSubTyping {
             // TODO: handle type params that are constrained by other type params
             // TODO: handle unconstrained types
 
-            var map = this.typeBounds.keySet().stream()
-                .map(typeArg -> {
-                    var inferredType = inferTypeArgType(typeArg);
+            var map = new HashMap<TypeLevelParam, TypeLevelValue>();
 
-                    return Map.<TypeLevelParam, TypeLevelValue>entry(typeArg.param(), inferredType);
-                })
-                .collect(Collectors.toMap(x -> x.getKey(), x -> x.getValue()));
+            for (var typeBoundsEntry : this.typeBounds.entrySet()) {
+                var typeArg = typeBoundsEntry.getKey();
+                var typeBounds = typeBoundsEntry.getValue();
+                var inferredType = solveBounds(typeBounds);
+                map.put(typeArg.param(), inferredType);
+            }
 
             return new TypeSubstitutionMap(map);
         }
 
-        private Type inferTypeArgType(TypeArg typeArg) {
-            var typeParamBounds = this.typeBounds.getOrDefault(typeArg, TypeBounds.EMPTY);
-
+        private Type solveBounds(TypeBounds typeParamBounds) {
             var lowerBound = Types.BOTTOM;
             for (var lower : typeParamBounds.lower) {
                 lowerBound = Types.commonSupertype(
@@ -116,10 +113,9 @@ public class TypeCheckerSubTyping {
                 throw new IllegalStateException("Incompatible type bounds");
             }
 
-            var inferredType = typeParamBounds.lower.isEmpty() && !typeParamBounds.upper.isEmpty()
+            return typeParamBounds.lower.isEmpty() && !typeParamBounds.upper.isEmpty()
                 ? upperBound
                 : lowerBound;
-            return inferredType;
         }
     }
 
-- 
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