Chapter 29: Tech Debt Cleanuplinear-chapter29linear

Co-authored-by: Hsiang-Ying Fu <66062782+fuhsnn@users.noreply.github.com>
Co-authored-by: fuhsnn <66062782+fuhsnn@users.noreply.github.com>
Co-authored-by: Symious <14933944+symious@users.noreply.github.com>
Co-authored-by: Jun Kawasaki <jun784@gmail.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 72 insertions, 0 deletions

diff --git a/src/main/java/com/seaofnodes/simple/parser/Conversions.java b/src/main/java/com/seaofnodes/simple/parser/Conversions.java
new file mode 100644
index 00000000..d50e2031
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/parser/Conversions.java
@@ -0,0 +1,72 @@
+package com.seaofnodes.simple.parser;
+
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.*;
+
+/** Shared declaration, assignment, and return conversions. */
+final class Conversions {
+    private final Parser P;
+
+    Conversions(Parser P) { this.P = P; }
+
+    // Widen ints to floats; narrow wide int types.
+    // Early error if types do not match variable.
+    Node convertExpr( Node expr, Type t ) {
+        if( !expr._type.accessISA(t) )
+            throw P.error("Type "+expr._type.str()+" is not of declared type "+t.str());
+        if( t instanceof TypeMemPtr tmp && tmp.isFinal() )
+            expr = P.peep(new ReadOnlyNode(expr));
+        // A FunPtr carries the semantic edge to its function's Return.  Do not
+        // hide that edge behind a Convert which can fold to a plain constant.
+        if( expr instanceof FunPtrNode && t instanceof TypeFunPtr )
+            return expr;
+        // Auto-widen array to i64 (cast ptr to raw int bits)
+        if( t == TypeInteger.BOT && expr._type instanceof TypeMemPtr tmp && tmp._obj.isAry() )
+            return P.peep(new AddNode(P.peep(new PtrToIntNode(expr)),Parser.off(tmp._obj,"[]")));
+        // Widen ints to floats, narrow wide types
+        return P.peep(new ConvertNode(t,expr));
+    }
+
+    // Inferred `var` declarations describe writable slots, not the exact
+    // value used to initialize them.  Explicitly typed locals retain the
+    // user's nullability and numeric-width guarantees; `val` retains the
+    // initializer's precise type.
+    static Type mutableInferredType(Type t) {
+        return switch( t ) {
+        case TypeInteger ti -> TypeInteger.BOT;
+        case TypeFloat   tf -> TypeFloat.F64;
+        case TypeMemPtr tmp -> tmp.makeVar();
+        case TypeFunPtr tfp -> tfp;
+        case TypeConAry<?> a -> a;
+        case TypePtr     ptr -> TypePtr.PTR;
+        case TypeScalar  ts -> TypeScalar.BOT;
+        default             -> t;
+        };
+    }
+
+    Type constructorFieldType(Type t) {
+        if( t instanceof TypeMemPtr ptr && ptr._obj.isConAry() ) {
+            TypeStruct declared = (TypeStruct)Parser.TYPES.get(ptr._obj._name);
+            TypeStruct shape = P.types.typeAry(declared._fields[1]._t,ptr._obj._fields[1]._final);
+            return TypeMemPtr.make((byte)2,shape,false).withAccess(ptr._ro);
+        }
+        return mutableInferredType(t);
+    }
+
+    // Seed an inferred return merge with the declared numeric family instead
+    // of a transient constant/range.  Pointer nullability remains part of the
+    // inferred function result and is combined by the later Phi.
+    static Type inferredReturnType(Type t) {
+        return switch( t ) {
+        case TypeInteger ti -> TypeInteger.BOT;
+        case TypeFloat   tf -> TypeFloat.F64;
+        default             -> t;
+        };
+    }
+
+    Node widenInt( Node expr, Type t ) {
+        return (expr._type instanceof TypeInteger || expr._type==Type.NIL) && t instanceof TypeFloat
+            ? P.peep(new ToFloatNode(expr)) : expr;
+    }
+
+}