Use a special 'auto' type in type inference

src/builtins.ts

@@ -648,7 +648,7 @@ export function compileCall(
         checkTypeAbsent(typeArguments, reportNode, prototype) |
         checkArgsRequired(operands, 1, reportNode, compiler)
       ) return module.unreachable();
-      let expr = compiler.compileExpressionRetainType(operands[0], Type.i32);
+      let expr = compiler.compileExpression(operands[0], Type.auto);
       compiler.currentType = Type.bool;
       return module.i32(getExpressionId(expr) == ExpressionId.Const ? 1 : 0);
     }
@@ -1555,6 +1555,7 @@ export function compileCall(
       ) return module.unreachable();
       let type = typeArguments![0];
       let outType = (
+        contextualType != Type.auto &&
         type.is(TypeFlags.INTEGER) &&
         contextualType.is(TypeFlags.INTEGER) &&
         contextualType.size > type.size
@@ -1965,7 +1966,7 @@ export function compileCall(
       ) return module.unreachable();
       let arg0 = typeArguments
         ? compiler.compileExpression(operands[0], typeArguments[0], ContextualFlags.IMPLICIT)
-        : compiler.compileExpressionRetainType(operands[0], Type.i32);
+        : compiler.compileExpression(operands[0], Type.auto);
       let type = compiler.currentType;
       if (!type.isAny(TypeFlags.VALUE | TypeFlags.REFERENCE)) {
         compiler.error(
@@ -1976,7 +1977,7 @@ export function compileCall(
       }
       let arg1 = compiler.compileExpression(operands[1], type, ContextualFlags.IMPLICIT);
       let arg2 = compiler.makeIsTrueish(
-        compiler.compileExpressionRetainType(operands[2], Type.bool),
+        compiler.compileExpression(operands[2], Type.bool),
         compiler.currentType // ^
       );
       compiler.currentType = type;
@@ -2060,7 +2061,7 @@ export function compileCall(
         checkArgsRequired(operands, 1, reportNode, compiler)
       ) return module.unreachable();
       let toType = typeArguments![0];
-      let arg0 = compiler.compileExpressionRetainType(operands[0], toType);
+      let arg0 = compiler.compileExpression(operands[0], toType);
       let fromType = compiler.currentType;
       compiler.currentType = toType;
       if (fromType.size != toType.size) {
@@ -2085,7 +2086,7 @@ export function compileCall(
       }
       let arg0 = typeArguments
         ? compiler.compileExpression(operands[0], typeArguments[0], ContextualFlags.IMPLICIT | ContextualFlags.WRAP)
-        : compiler.compileExpressionRetainType(operands[0], Type.bool, ContextualFlags.WRAP);
+        : compiler.compileExpression(operands[0], Type.bool, ContextualFlags.WRAP);
       let type = compiler.currentType;
       compiler.currentType = type.nonNullableType;
 
@@ -2272,7 +2273,7 @@ export function compileCall(
         checkArgsOptional(operands, 1, i32.MAX_VALUE, reportNode, compiler)
       ) return module.unreachable();
       let returnType = typeArguments ? typeArguments[0] : contextualType;
-      let arg0 = compiler.compileExpressionRetainType(operands[0], Type.u32);
+      let arg0 = compiler.compileExpression(operands[0], Type.u32);
       let arg0Type = compiler.currentType;
       if (!(
         arg0Type == Type.u32 ||                                      // either plain index
@@ -2290,7 +2291,7 @@ export function compileCall(
       let parameterTypes = new Array<Type>(numOperands);
       let nativeParamTypes = new Array<NativeType>(numOperands);
       for (let i = 0; i < numOperands; ++i) {
-        operandExprs[i] = compiler.compileExpressionRetainType(operands[1 + i], Type.i32);
+        operandExprs[i] = compiler.compileExpression(operands[1 + i], Type.i32);
         let operandType = compiler.currentType;
         parameterTypes[i] = operandType;
         nativeParamTypes[i] = operandType.toNativeType();
@@ -4232,21 +4233,17 @@ function evaluateConstantType(
     return typeArguments[0];
   }
   if (operands.length == 1) { // optional type argument
-    if (typeArguments) {
+    if (typeArguments !== null && typeArguments.length) {
-      if (typeArguments.length == 1) {
+      if (typeArguments.length > 1) {
-        compiler.compileExpression(operands[0], typeArguments[0], ContextualFlags.IMPLICIT);
+        compiler.error(
-      } else {
+          DiagnosticCode.Expected_0_type_arguments_but_got_1,
-        if (typeArguments.length) {
+          reportNode.typeArgumentsRange, "1", typeArguments.length.toString(10)
-          compiler.error(
+        );
-            DiagnosticCode.Expected_0_type_arguments_but_got_1,
+        return null;
-            reportNode.typeArgumentsRange, "1", typeArguments.length.toString(10)
-          );
-          return null;
-        }
-        compiler.compileExpressionRetainType(operands[0], Type.i32);
       }
+      compiler.compileExpression(operands[0], typeArguments[0], ContextualFlags.IMPLICIT);
     } else {
-      compiler.compileExpressionRetainType(operands[0], Type.i32);
+      compiler.compileExpression(operands[0], Type.auto);
     }
     return compiler.currentType;
   }

src/compiler.ts

@@ -248,10 +248,8 @@ export const enum ContextualFlags {
   WILL_DROP = 1 << 3,
   /** Value is known to be immediately assigned to a retaining target.  */
   SKIP_AUTORELEASE = 1 << 4,
-  /** Is the last statement in a function body. */
-  LAST_IN_BODY = 1 << 5,
   /** Data can be compiled statically. */
-  STATIC_CAPABLE = 1 << 6
+  STATIC_CAPABLE = 1 << 5
 }
 
 /** Runtime features to be activated by the compiler. */
@@ -814,7 +812,7 @@ export class Compiler extends DiagnosticEmitter {
         if (global.hasDecorator(DecoratorFlags.LAZY)) {
           this.currentFlow = global.file.startFunction.flow;
         }
-        initExpr = this.compileExpression(initializerNode, Type.i32, // reports
+        initExpr = this.compileExpression(initializerNode, Type.auto, // reports
           ContextualFlags.WRAP | ContextualFlags.SKIP_AUTORELEASE
         );
         if (this.skippedAutoreleases.has(initExpr)) initAutoreleaseSkipped = true;
@@ -1686,70 +1684,70 @@ export class Compiler extends DiagnosticEmitter {
 
   compileStatement(
     statement: Statement,
-    contextualFlags: ContextualFlags = ContextualFlags.NONE
+    isLastInBody: bool = false
   ): ExpressionRef {
     var module = this.module;
     var stmt: ExpressionRef;
     switch (statement.kind) {
       case NodeKind.BLOCK: {
-        stmt = this.compileBlockStatement(<BlockStatement>statement, contextualFlags);
+        stmt = this.compileBlockStatement(<BlockStatement>statement);
         break;
       }
       case NodeKind.BREAK: {
-        stmt = this.compileBreakStatement(<BreakStatement>statement, contextualFlags);
+        stmt = this.compileBreakStatement(<BreakStatement>statement);
         break;
       }
       case NodeKind.CONTINUE: {
-        stmt = this.compileContinueStatement(<ContinueStatement>statement, contextualFlags);
+        stmt = this.compileContinueStatement(<ContinueStatement>statement);
         break;
       }
       case NodeKind.DO: {
-        stmt = this.compileDoStatement(<DoStatement>statement, contextualFlags);
+        stmt = this.compileDoStatement(<DoStatement>statement);
         break;
       }
       case NodeKind.EMPTY: {
-        stmt = this.compileEmptyStatement(<EmptyStatement>statement, contextualFlags);
+        stmt = this.compileEmptyStatement(<EmptyStatement>statement);
         break;
       }
       case NodeKind.EXPRESSION: {
-        stmt = this.compileExpressionStatement(<ExpressionStatement>statement, contextualFlags);
+        stmt = this.compileExpressionStatement(<ExpressionStatement>statement);
         break;
       }
       case NodeKind.FOR: {
-        stmt = this.compileForStatement(<ForStatement>statement, contextualFlags);
+        stmt = this.compileForStatement(<ForStatement>statement);
         break;
       }
       case NodeKind.IF: {
-        stmt = this.compileIfStatement(<IfStatement>statement, contextualFlags);
+        stmt = this.compileIfStatement(<IfStatement>statement);
         break;
       }
       case NodeKind.RETURN: {
-        stmt = this.compileReturnStatement(<ReturnStatement>statement, contextualFlags);
+        stmt = this.compileReturnStatement(<ReturnStatement>statement, isLastInBody);
         break;
       }
       case NodeKind.SWITCH: {
-        stmt = this.compileSwitchStatement(<SwitchStatement>statement, contextualFlags);
+        stmt = this.compileSwitchStatement(<SwitchStatement>statement);
         break;
       }
       case NodeKind.THROW: {
-        stmt = this.compileThrowStatement(<ThrowStatement>statement, contextualFlags);
+        stmt = this.compileThrowStatement(<ThrowStatement>statement);
         break;
       }
       case NodeKind.TRY: {
-        stmt = this.compileTryStatement(<TryStatement>statement, contextualFlags);
+        stmt = this.compileTryStatement(<TryStatement>statement);
         break;
       }
       case NodeKind.VARIABLE: {
-        stmt = this.compileVariableStatement(<VariableStatement>statement, contextualFlags);
+        stmt = this.compileVariableStatement(<VariableStatement>statement);
         if (!stmt) stmt = module.nop();
         break;
       }
       case NodeKind.VOID: {
-        stmt = this.compileVoidStatement(<VoidStatement>statement, contextualFlags);
+        stmt = this.compileVoidStatement(<VoidStatement>statement);
         break;
       }
       case NodeKind.WHILE: {
-        stmt = this.compileWhileStatement(<WhileStatement>statement, contextualFlags);
+        stmt = this.compileWhileStatement(<WhileStatement>statement);
         break;
       }
       case NodeKind.TYPEDECLARATION: {
@@ -1783,11 +1781,7 @@ export class Compiler extends DiagnosticEmitter {
     var module = this.module;
     var flow = this.currentFlow;
     for (let i = 0; i < numStatements; ++i) {
-      let stmt = this.compileStatement(statements[i],
+      let stmt = this.compileStatement(statements[i], isBody && i == numStatements - 1);
-        isBody && i == numStatements - 1
-          ? ContextualFlags.LAST_IN_BODY
-          : ContextualFlags.NONE
-      );
       switch (getExpressionId(stmt)) {
         case ExpressionId.Block: {
           if (!getBlockName(stmt)) {
@@ -1808,8 +1802,7 @@ export class Compiler extends DiagnosticEmitter {
   }
 
   compileBlockStatement(
-    statement: BlockStatement,
+    statement: BlockStatement
-    contextualFlags: ContextualFlags
   ): ExpressionRef {
     var statements = statement.statements;
     var outerFlow = this.currentFlow;
@@ -1825,8 +1818,7 @@ export class Compiler extends DiagnosticEmitter {
   }
 
   compileBreakStatement(
-    statement: BreakStatement,
+    statement: BreakStatement
-    contextualFlags: ContextualFlags
   ): ExpressionRef {
     var module = this.module;
     if (statement.label) {
@@ -1859,8 +1851,7 @@ export class Compiler extends DiagnosticEmitter {
   }
 
   compileContinueStatement(
-    statement: ContinueStatement,
+    statement: ContinueStatement
-    contextualFlags: ContextualFlags
   ): ExpressionRef {
     var module = this.module;
     var label = statement.label;
@@ -1895,8 +1886,7 @@ export class Compiler extends DiagnosticEmitter {
   }
 
   compileDoStatement(
-    statement: DoStatement,
+    statement: DoStatement
-    contextualFlags: ContextualFlags
   ): ExpressionRef {
     var module = this.module;
 
@@ -1967,24 +1957,19 @@ export class Compiler extends DiagnosticEmitter {
   }
 
   compileEmptyStatement(
-    statement: EmptyStatement,
+    statement: EmptyStatement
-    contextualFlags: ContextualFlags
   ): ExpressionRef {
     return this.module.nop();
   }
 
   compileExpressionStatement(
-    statement: ExpressionStatement,
+    statement: ExpressionStatement
-    contextualFlags: ContextualFlags,
   ): ExpressionRef {
-    return this.compileExpression(statement.expression, Type.void,
+    return this.compileExpression(statement.expression, Type.void, ContextualFlags.IMPLICIT);
-      contextualFlags | ContextualFlags.EXPLICIT | ContextualFlags.WILL_DROP
-    );
   }
 
   compileForStatement(
-    statement: ForStatement,
+    statement: ForStatement
-    contextualFlags: ContextualFlags
   ): ExpressionRef {
     var module = this.module;
 
@@ -2005,7 +1990,7 @@ export class Compiler extends DiagnosticEmitter {
     if (statement.condition) {
       condExpr = module.precomputeExpression(
         this.makeIsTrueish(
-          this.compileExpressionRetainType(<Expression>statement.condition, Type.bool),
+          this.compileExpression(<Expression>statement.condition, Type.bool),
           this.currentType
         )
       );
@@ -2113,8 +2098,7 @@ export class Compiler extends DiagnosticEmitter {
   }
 
   compileIfStatement(
-    statement: IfStatement,
+    statement: IfStatement
-    contextualFlags: ContextualFlags
   ): ExpressionRef {
     var module = this.module;
     var ifTrue = statement.ifTrue;
@@ -2124,7 +2108,7 @@ export class Compiler extends DiagnosticEmitter {
     // The condition doesn't initiate a branch yet
     var condExpr = module.precomputeExpression(
       this.makeIsTrueish(
-        this.compileExpressionRetainType(statement.condition, Type.bool),
+        this.compileExpression(statement.condition, Type.bool),
         this.currentType
       )
     );
@@ -2189,7 +2173,7 @@ export class Compiler extends DiagnosticEmitter {
 
   compileReturnStatement(
     statement: ReturnStatement,
-    contextualFlags: ContextualFlags
+    isLastInBody: bool
   ): ExpressionRef {
     var module = this.module;
     var expr: ExpressionRef = 0;
@@ -2256,7 +2240,7 @@ export class Compiler extends DiagnosticEmitter {
     flow.freeScopedLocals();
 
     // If the last statement anyway, make it the block's return value
-    if ((contextualFlags & ContextualFlags.LAST_IN_BODY) != 0 && expr && returnType != Type.void) {
+    if (isLastInBody && expr && returnType != Type.void) {
       if (!stmts.length) return expr;
       stmts.push(expr);
       return module.block(null, stmts, returnType.toNativeType());
@@ -2276,7 +2260,9 @@ export class Compiler extends DiagnosticEmitter {
     return module.block(null, stmts);
   }
 
-  compileSwitchStatement(statement: SwitchStatement, contextualFlags: ContextualFlags): ExpressionRef {
+  compileSwitchStatement(
+    statement: SwitchStatement
+  ): ExpressionRef {
     var module = this.module;
 
     var cases = statement.cases;
@@ -2389,8 +2375,7 @@ export class Compiler extends DiagnosticEmitter {
   }
 
   compileThrowStatement(
-    statement: ThrowStatement,
+    statement: ThrowStatement
-    contextualFlags: ContextualFlags
   ): ExpressionRef {
     var flow = this.currentFlow;
 
@@ -2413,8 +2398,7 @@ export class Compiler extends DiagnosticEmitter {
   }
 
   compileTryStatement(
-    statement: TryStatement,
+    statement: TryStatement
-    contextualFlags: ContextualFlags
   ): ExpressionRef {
     // TODO: can't yet support something like: try { return ... } finally { ... }
     // worthwhile to investigate lowering returns to block results (here)?
@@ -2426,7 +2410,9 @@ export class Compiler extends DiagnosticEmitter {
   }
 
   /** Compiles a variable statement. Returns `0` if an initializer is not necessary. */
-  compileVariableStatement(statement: VariableStatement, contextualFlags: ContextualFlags): ExpressionRef {
+  compileVariableStatement(
+    statement: VariableStatement
+  ): ExpressionRef {
     var module = this.module;
     var declarations = statement.declarations;
     var numDeclarations = declarations.length;
@@ -2458,7 +2444,7 @@ export class Compiler extends DiagnosticEmitter {
 
       // Otherwise infer type from initializer
       } else if (declaration.initializer) {
-        initExpr = this.compileExpressionRetainType(declaration.initializer, Type.void,
+        initExpr = this.compileExpression(declaration.initializer, Type.auto,
           ContextualFlags.SKIP_AUTORELEASE
         ); // reports
         initAutoreleaseSkipped = this.skippedAutoreleases.has(initExpr);
@@ -2617,20 +2603,24 @@ export class Compiler extends DiagnosticEmitter {
       : flatten(module, initializers, NativeType.None);
   }
 
-  compileVoidStatement(statement: VoidStatement, contextualFlags: ContextualFlags): ExpressionRef {
+  compileVoidStatement(
+    statement: VoidStatement
+  ): ExpressionRef {
     return this.compileExpression(statement.expression, Type.void,
       ContextualFlags.EXPLICIT | ContextualFlags.WILL_DROP
     );
   }
 
-  compileWhileStatement(statement: WhileStatement, contextualFlags: ContextualFlags): ExpressionRef {
+  compileWhileStatement(
+    statement: WhileStatement
+  ): ExpressionRef {
     var module = this.module;
     var outerFlow = this.currentFlow;
 
     // Compile condition
     var condExpr = module.precomputeExpression(
       this.makeIsTrueish(
-        this.compileExpressionRetainType(statement.condition, Type.bool),
+        this.compileExpression(statement.condition, Type.bool),
         this.currentType
       )
     );
@@ -2885,20 +2875,6 @@ export class Compiler extends DiagnosticEmitter {
     return expr;
   }
 
-  /** Compiles an expression while retaining the type, that is not void, it ultimately compiles to. */
-  compileExpressionRetainType(
-    expression: Expression,
-    contextualType: Type,
-    contextualFlags: ContextualFlags = ContextualFlags.NONE
-  ): ExpressionRef {
-    return this.compileExpression(expression,
-      contextualType == Type.void
-        ? Type.i32 // default to i32
-        : contextualType,
-      (contextualFlags & ~(ContextualFlags.IMPLICIT | ContextualFlags.EXPLICIT))
-    );
-  }
-
   /** Compiles and precomputes an expression, possibly yielding a costant value. */
   precomputeExpression(
     expression: Expression,
@@ -3108,6 +3084,7 @@ export class Compiler extends DiagnosticEmitter {
     contextualType: Type,
     contextualFlags: ContextualFlags
   ): ExpressionRef {
+    var inheritedFlags = contextualFlags & ~(ContextualFlags.IMPLICIT | ContextualFlags.EXPLICIT);
     switch (expression.assertionKind) {
       case AssertionKind.PREFIX:
       case AssertionKind.AS: {
@@ -3118,13 +3095,11 @@ export class Compiler extends DiagnosticEmitter {
           flow.contextualTypeArguments
         );
         if (!toType) return this.module.unreachable();
-        return this.compileExpression(expression.expression, toType,
+        return this.compileExpression(expression.expression, toType, inheritedFlags | ContextualFlags.EXPLICIT);
-          contextualFlags | ContextualFlags.EXPLICIT
-        );
       }
       case AssertionKind.NONNULL: {
         assert(!expression.toType);
-        let expr = this.compileExpressionRetainType(expression.expression, contextualType);
+        let expr = this.compileExpression(expression.expression, contextualType.exceptVoid, inheritedFlags);
         let type = this.currentType;
         if (this.currentFlow.isNonnull(expr, type)) {
           this.info(
@@ -3177,7 +3152,7 @@ export class Compiler extends DiagnosticEmitter {
     var operator = expression.operator;
     switch (operator) {
       case Token.LESSTHAN: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType);
+        leftExpr = this.compileExpression(left, contextualType);
         leftType = this.currentType;
 
         // check operator overload
@@ -3197,7 +3172,7 @@ export class Compiler extends DiagnosticEmitter {
           return this.module.unreachable();
         }
 
-        rightExpr = this.compileExpressionRetainType(right, leftType);
+        rightExpr = this.compileExpression(right, leftType);
         rightType = this.currentType;
         if (commonType = Type.commonDenominator(leftType, rightType, true)) {
           leftExpr = this.convertExpression(leftExpr,
@@ -3277,7 +3252,7 @@ export class Compiler extends DiagnosticEmitter {
         break;
       }
       case Token.GREATERTHAN: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType);
+        leftExpr = this.compileExpression(left, contextualType);
         leftType = this.currentType;
 
         // check operator overload
@@ -3297,7 +3272,7 @@ export class Compiler extends DiagnosticEmitter {
           return this.module.unreachable();
         }
 
-        rightExpr = this.compileExpressionRetainType(right, leftType);
+        rightExpr = this.compileExpression(right, leftType);
         rightType = this.currentType;
         if (commonType = Type.commonDenominator(leftType, rightType, true)) {
           leftExpr = this.convertExpression(leftExpr,
@@ -3377,7 +3352,7 @@ export class Compiler extends DiagnosticEmitter {
         break;
       }
       case Token.LESSTHAN_EQUALS: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType);
+        leftExpr = this.compileExpression(left, contextualType);
         leftType = this.currentType;
 
         // check operator overload
@@ -3397,7 +3372,7 @@ export class Compiler extends DiagnosticEmitter {
           return this.module.unreachable();
         }
 
-        rightExpr = this.compileExpressionRetainType(right, leftType);
+        rightExpr = this.compileExpression(right, leftType);
         rightType = this.currentType;
         if (commonType = Type.commonDenominator(leftType, rightType, true)) {
           leftExpr = this.convertExpression(leftExpr,
@@ -3477,7 +3452,7 @@ export class Compiler extends DiagnosticEmitter {
         break;
       }
       case Token.GREATERTHAN_EQUALS: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType);
+        leftExpr = this.compileExpression(left, contextualType);
         leftType = this.currentType;
 
         // check operator overload
@@ -3497,7 +3472,7 @@ export class Compiler extends DiagnosticEmitter {
           return this.module.unreachable();
         }
 
-        rightExpr = this.compileExpressionRetainType(right, leftType);
+        rightExpr = this.compileExpression(right, leftType);
         rightType = this.currentType;
         if (commonType = Type.commonDenominator(leftType, rightType, true)) {
           leftExpr = this.convertExpression(leftExpr,
@@ -3584,7 +3559,7 @@ export class Compiler extends DiagnosticEmitter {
         // checking for a possible use of unary EQZ. while the most classic of all optimizations,
         // that's not what the source told us to do. for reference, `!left` emits unary EQZ.
 
-        leftExpr = this.compileExpressionRetainType(left, contextualType);
+        leftExpr = this.compileExpression(left, contextualType);
         leftType = this.currentType;
 
          // check operator overload
@@ -3600,7 +3575,7 @@ export class Compiler extends DiagnosticEmitter {
           // still allow '==' with references
         }
 
-        rightExpr = this.compileExpressionRetainType(right, leftType);
+        rightExpr = this.compileExpression(right, leftType);
         rightType = this.currentType;
         if (commonType = Type.commonDenominator(leftType, rightType, false)) {
           leftExpr = this.convertExpression(leftExpr,
@@ -3672,7 +3647,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.EXCLAMATION_EQUALS_EQUALS:
       case Token.EXCLAMATION_EQUALS: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType);
+        leftExpr = this.compileExpression(left, contextualType);
         leftType = this.currentType;
 
          // check operator overload
@@ -3688,7 +3663,7 @@ export class Compiler extends DiagnosticEmitter {
           // still allow '!=' with references
         }
 
-        rightExpr = this.compileExpressionRetainType(right, leftType);
+        rightExpr = this.compileExpression(right, leftType);
         rightType = this.currentType;
         if (commonType = Type.commonDenominator(leftType, rightType, false)) {
           leftExpr = this.convertExpression(leftExpr,
@@ -3763,7 +3738,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.PLUS_EQUALS: compound = true;
       case Token.PLUS: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType);
+        leftExpr = this.compileExpression(left, contextualType);
         leftType = this.currentType;
 
         // check operator overload
@@ -3786,7 +3761,7 @@ export class Compiler extends DiagnosticEmitter {
         if (compound) {
           rightExpr = this.compileExpression(right, leftType, ContextualFlags.IMPLICIT);
         } else {
-          rightExpr = this.compileExpressionRetainType(right, leftType);
+          rightExpr = this.compileExpression(right, leftType);
           rightType = this.currentType;
           if (commonType = Type.commonDenominator(leftType, rightType, false)) {
             leftExpr = this.convertExpression(leftExpr,
@@ -3852,7 +3827,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.MINUS_EQUALS: compound = true;
       case Token.MINUS: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType);
+        leftExpr = this.compileExpression(left, contextualType);
         leftType = this.currentType;
 
         // check operator overload
@@ -3876,7 +3851,7 @@ export class Compiler extends DiagnosticEmitter {
           rightExpr = this.compileExpression(right, leftType, ContextualFlags.IMPLICIT);
           rightType = this.currentType;
         } else {
-          rightExpr = this.compileExpressionRetainType(right, leftType);
+          rightExpr = this.compileExpression(right, leftType);
           rightType = this.currentType;
           if (commonType = Type.commonDenominator(leftType, rightType, false)) {
             leftExpr = this.convertExpression(leftExpr,
@@ -3942,7 +3917,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.ASTERISK_EQUALS: compound = true;
       case Token.ASTERISK: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType);
+        leftExpr = this.compileExpression(left, contextualType);
         leftType = this.currentType;
 
         // check operator overload
@@ -3966,7 +3941,7 @@ export class Compiler extends DiagnosticEmitter {
           leftExpr = this.ensureSmallIntegerWrap(leftExpr, leftType);
           rightExpr = this.compileExpression(right, leftType, ContextualFlags.IMPLICIT);
         } else {
-          rightExpr = this.compileExpressionRetainType(right, leftType);
+          rightExpr = this.compileExpression(right, leftType);
           rightType = this.currentType;
           if (commonType = Type.commonDenominator(leftType, rightType, false)) {
             leftExpr = this.convertExpression(leftExpr,
@@ -4032,7 +4007,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.ASTERISK_ASTERISK_EQUALS: compound = true;
       case Token.ASTERISK_ASTERISK: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType);
+        leftExpr = this.compileExpression(left, contextualType);
         leftType = this.currentType;
 
         // check operator overload
@@ -4124,7 +4099,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.SLASH_EQUALS: compound = true;
       case Token.SLASH: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType);
+        leftExpr = this.compileExpression(left, contextualType);
         leftType = this.currentType;
 
         // check operator overload
@@ -4149,7 +4124,7 @@ export class Compiler extends DiagnosticEmitter {
           rightExpr = this.compileExpression(right, leftType, ContextualFlags.IMPLICIT);
           rightType = this.currentType;
         } else {
-          rightExpr = this.compileExpressionRetainType(right, leftType);
+          rightExpr = this.compileExpression(right, leftType);
           rightType = this.currentType;
           if (commonType = Type.commonDenominator(leftType, rightType, false)) {
             leftExpr = this.convertExpression(leftExpr,
@@ -4233,7 +4208,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.PERCENT_EQUALS: compound = true;
       case Token.PERCENT: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType);
+        leftExpr = this.compileExpression(left, contextualType);
         leftType = this.currentType;
 
         // check operator overload
@@ -4258,7 +4233,7 @@ export class Compiler extends DiagnosticEmitter {
           rightExpr = this.compileExpression(right, leftType, ContextualFlags.IMPLICIT);
           rightType = this.currentType;
         } else {
-          rightExpr = this.compileExpressionRetainType(right, leftType);
+          rightExpr = this.compileExpression(right, leftType);
           rightType = this.currentType;
           if (commonType = Type.commonDenominator(leftType, rightType, false)) {
             leftExpr = this.convertExpression(leftExpr,
@@ -4399,7 +4374,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.LESSTHAN_LESSTHAN_EQUALS: compound = true;
       case Token.LESSTHAN_LESSTHAN: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType.intType);
+        leftExpr = this.compileExpression(left, contextualType.intType);
         leftType = this.currentType;
 
         // check operator overload
@@ -4465,7 +4440,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.GREATERTHAN_GREATERTHAN_EQUALS: compound = true;
       case Token.GREATERTHAN_GREATERTHAN: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType.intType);
+        leftExpr = this.compileExpression(left, contextualType.intType);
         leftType = this.currentType;
 
         // check operator overload
@@ -4553,7 +4528,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.GREATERTHAN_GREATERTHAN_GREATERTHAN_EQUALS: compound = true;
       case Token.GREATERTHAN_GREATERTHAN_GREATERTHAN: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType.intType);
+        leftExpr = this.compileExpression(left, contextualType.intType);
         leftType = this.currentType;
 
         // check operator overload
@@ -4622,7 +4597,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.AMPERSAND_EQUALS: compound = true;
       case Token.AMPERSAND: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType.intType);
+        leftExpr = this.compileExpression(left, contextualType.intType);
         leftType = this.currentType;
 
         // check operator overloadd
@@ -4646,7 +4621,7 @@ export class Compiler extends DiagnosticEmitter {
           rightExpr = this.compileExpression(right, leftType, ContextualFlags.IMPLICIT);
           rightType = this.currentType;
         } else {
-          rightExpr = this.compileExpressionRetainType(right, leftType);
+          rightExpr = this.compileExpression(right, leftType);
           rightType = this.currentType;
           if (commonType = Type.commonDenominator(leftType, rightType, false)) {
             leftExpr = this.convertExpression(leftExpr,
@@ -4712,7 +4687,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.BAR_EQUALS: compound = true;
       case Token.BAR: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType.intType);
+        leftExpr = this.compileExpression(left, contextualType.intType);
         leftType = this.currentType;
 
         // check operator overload
@@ -4736,7 +4711,7 @@ export class Compiler extends DiagnosticEmitter {
           rightExpr = this.compileExpression(right, leftType, ContextualFlags.IMPLICIT);
           rightType = this.currentType;
         } else {
-          rightExpr = this.compileExpressionRetainType(right, leftType);
+          rightExpr = this.compileExpression(right, leftType);
           rightType = this.currentType;
           if (commonType = Type.commonDenominator(leftType, rightType, false)) {
             leftExpr = this.convertExpression(leftExpr,
@@ -4805,7 +4780,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.CARET_EQUALS: compound = true;
       case Token.CARET: {
-        leftExpr = this.compileExpressionRetainType(left, contextualType.intType);
+        leftExpr = this.compileExpression(left, contextualType.intType);
         leftType = this.currentType;
 
         // check operator overload
@@ -4829,7 +4804,7 @@ export class Compiler extends DiagnosticEmitter {
           rightExpr = this.compileExpression(right, leftType, ContextualFlags.IMPLICIT);
           rightType = this.currentType;
         } else {
-          rightExpr = this.compileExpressionRetainType(right, leftType);
+          rightExpr = this.compileExpression(right, leftType);
           rightType = this.currentType;
           if (commonType = Type.commonDenominator(leftType, rightType, false)) {
             leftExpr = this.convertExpression(leftExpr,
@@ -4901,13 +4876,14 @@ export class Compiler extends DiagnosticEmitter {
 
       case Token.AMPERSAND_AMPERSAND: { // left && right -> (t = left) ? right : t
         let flow = this.currentFlow;
-        leftExpr = this.compileExpressionRetainType(left, contextualType, contextualFlags);
+        let inheritedFlags = contextualFlags & (ContextualFlags.SKIP_AUTORELEASE | ContextualFlags.WRAP);
+        leftExpr = this.compileExpression(left, contextualType.exceptVoid, inheritedFlags);
         leftType = this.currentType;
 
         let rightFlow = flow.fork();
         this.currentFlow = rightFlow;
         rightFlow.inheritNonnullIfTrue(leftExpr);
-        rightExpr = this.compileExpression(right, leftType, ContextualFlags.IMPLICIT | (contextualFlags & ~ContextualFlags.WILL_DROP));
+        rightExpr = this.compileExpression(right, leftType, inheritedFlags | ContextualFlags.IMPLICIT);
         rightType = leftType;
 
         // simplify if only interested in true or false
@@ -4998,13 +4974,14 @@ export class Compiler extends DiagnosticEmitter {
       }
       case Token.BAR_BAR: { // left || right -> ((t = left) ? t : right)
         let flow = this.currentFlow;
-        leftExpr = this.compileExpressionRetainType(left, contextualType, contextualFlags);
+        let inheritedFlags = contextualFlags & (ContextualFlags.SKIP_AUTORELEASE | ContextualFlags.WRAP);
+        leftExpr = this.compileExpression(left, contextualType.exceptVoid, inheritedFlags);
         leftType = this.currentType;
 
         let rightFlow = flow.fork();
         this.currentFlow = rightFlow;
         rightFlow.inheritNonnullIfFalse(leftExpr);
-        rightExpr = this.compileExpression(right, leftType, ContextualFlags.IMPLICIT | contextualFlags);
+        rightExpr = this.compileExpression(right, leftType, inheritedFlags | ContextualFlags.IMPLICIT);
         rightType = leftType;
 
         // simplify if only interested in true or false
@@ -5326,11 +5303,8 @@ export class Compiler extends DiagnosticEmitter {
         }
         return this.makeFieldAssignment(<Field>target,
           valueExpr,
-          this.compileExpressionRetainType(
+          // FIXME: explicit type (currently fails due to missing null checking)
-            assert(thisExpression),
+          this.compileExpression(assert(thisExpression), this.options.usizeType),
-            // FIXME: explicit type (currently fails due to missing null checking)
-            this.options.usizeType
-          ),
           tee
         );
       }
@@ -5371,20 +5345,14 @@ export class Compiler extends DiagnosticEmitter {
         }
         // call just the setter if the return value isn't of interest
         if (!tee) {
-          let thisExpr = this.compileExpressionRetainType(
+          let thisExpr = this.compileExpression(assert(thisExpression), this.options.usizeType);
-            assert(thisExpression),
-            this.options.usizeType
-          );
           return this.makeCallDirect(setterInstance, [ thisExpr, valueExpr ], valueExpression);
         }
         // otherwise call the setter first, then the getter
         let getterInstance = assert((<Property>target).getterInstance); // must be present
         let returnType = getterInstance.signature.returnType;
         let nativeReturnType = returnType.toNativeType();
-        let thisExpr = this.compileExpressionRetainType(
+        let thisExpr = this.compileExpression(assert(thisExpression), this.options.usizeType);
-          assert(thisExpression),
-          this.options.usizeType
-        );
         let tempLocal = flow.getAndFreeTempLocal(returnType);
         let tempLocalIndex = tempLocal.index;
         return module.block(null, [
@@ -5419,10 +5387,7 @@ export class Compiler extends DiagnosticEmitter {
             return module.unreachable();
           }
           let targetType = (<Class>target).type;
-          let thisExpr = this.compileExpressionRetainType(
+          let thisExpr = this.compileExpression(assert(thisExpression), this.options.usizeType);
-            assert(thisExpression),
-            this.options.usizeType
-          );
           let elementExpr = this.compileExpression(indexExpression, Type.i32, ContextualFlags.IMPLICIT);
           if (tee) {
             let tempLocalTarget = flow.getTempLocal(targetType);
@@ -5868,7 +5833,7 @@ export class Compiler extends DiagnosticEmitter {
             if (templateName !== null && inferredTypes.has(templateName)) {
               let inferredType = inferredTypes.get(templateName);
               if (inferredType) {
-                argumentExprs[i] = this.compileExpressionRetainType(argumentExpression, inferredType);
+                argumentExprs[i] = this.compileExpression(argumentExpression, inferredType);
                 let commonType: Type | null;
                 if (!(commonType = Type.commonDenominator(inferredType, this.currentType, true))) {
                   if (!(commonType = Type.commonDenominator(inferredType, this.currentType, false))) {
@@ -5881,7 +5846,7 @@ export class Compiler extends DiagnosticEmitter {
                 }
                 inferredType = commonType;
               } else {
-                argumentExprs[i] = this.compileExpressionRetainType(argumentExpression, Type.i32);
+                argumentExprs[i] = this.compileExpression(argumentExpression, Type.auto);
                 inferredType = this.currentType;
                 // ++numInferred;
               }
@@ -5921,10 +5886,7 @@ export class Compiler extends DiagnosticEmitter {
         // compile 'this' expression if an instance method
         let thisExpr: ExpressionRef = 0;
         if (instance.is(CommonFlags.INSTANCE)) {
-          thisExpr = this.compileExpressionRetainType(
+          thisExpr = this.compileExpression(assert(this.resolver.currentThisExpression), this.options.usizeType);
-            assert(this.resolver.currentThisExpression),
-            this.options.usizeType
-          );
         }
 
         return this.compileCallDirect(
@@ -5969,10 +5931,7 @@ export class Compiler extends DiagnosticEmitter {
         let type = (<Field>target).type;
         if (signature = type.signatureReference) {
           let thisExpression = assert(this.resolver.currentThisExpression);
-          let thisExpr = this.compileExpressionRetainType(
+          let thisExpr = this.compileExpression(thisExpression, this.options.usizeType);
-            thisExpression,
-            this.options.usizeType
-          );
           indexArg = module.load(
             4,
             false,
@@ -6013,10 +5972,7 @@ export class Compiler extends DiagnosticEmitter {
       case ElementKind.PROPERTY: { // instance property
         let getterInstance = assert((<Property>target).getterInstance);
         indexArg = this.compileCallDirect(getterInstance, [], expression.expression,
-          this.compileExpressionRetainType(
+          this.compileExpression(assert(this.resolver.currentThisExpression), this.options.usizeType)
-            assert(this.resolver.currentThisExpression),
-            this.options.usizeType
-          )
         );
         signature = this.currentType.signatureReference;
         if (!signature) {
@@ -6579,6 +6535,7 @@ export class Compiler extends DiagnosticEmitter {
 
   /** Makes an automatic release call at the end of the current flow. */
   makeAutorelease(expr: ExpressionRef, flow: Flow = this.currentFlow): ExpressionRef {
+    // FIXME: loses track of nonNull state?
     return this.module.local_tee(flow.getAutoreleaseLocal(this.options.usizeType).index, expr);
   }
 
@@ -7325,7 +7282,7 @@ export class Compiler extends DiagnosticEmitter {
     // time of implementation, this seemed more useful because dynamic rhs expressions are not
     // possible in AS anyway. also note that the code generated below must preserve side-effects of
     // the LHS expression even when the result is a constant, i.e. return a block dropping `expr`.
-    var expr = this.compileExpressionRetainType(expression.expression, this.options.usizeType);
+    var expr = this.compileExpression(expression.expression, this.options.usizeType);
     var actualType = this.currentType;
     var expectedType = this.resolver.resolveType(expression.isType, this.currentFlow.actualFunction);
     this.currentType = Type.bool;
@@ -7986,10 +7943,7 @@ export class Compiler extends DiagnosticEmitter {
       }
       case ElementKind.FIELD: { // instance field
         assert((<Field>target).memoryOffset >= 0);
-        let thisExpr = this.compileExpressionRetainType(
+        let thisExpr = this.compileExpression(assert(this.resolver.currentThisExpression), this.options.usizeType);
-          assert(this.resolver.currentThisExpression),
-          this.options.usizeType
-        );
         this.currentType = (<Field>target).type;
         return module.load(
           (<Field>target).type.byteSize,
@@ -8010,10 +7964,7 @@ export class Compiler extends DiagnosticEmitter {
       case ElementKind.PROPERTY: { // instance property
         let getterInstance = assert((<Property>target).getterInstance);
         return this.compileCallDirect(getterInstance, [], propertyAccess,
-          this.compileExpressionRetainType(
+          this.compileExpression(assert(this.resolver.currentThisExpression), this.options.usizeType)
-            assert(this.resolver.currentThisExpression),
-            this.options.usizeType
-          )
         );
       }
       case ElementKind.FUNCTION_PROTOTYPE: {
@@ -8042,7 +7993,7 @@ export class Compiler extends DiagnosticEmitter {
 
     var condExpr = this.module.precomputeExpression(
       this.makeIsTrueish(
-        this.compileExpressionRetainType(expression.condition, Type.bool),
+        this.compileExpression(expression.condition, Type.bool),
         this.currentType
       )
     );
@@ -8053,19 +8004,19 @@ export class Compiler extends DiagnosticEmitter {
       getExpressionType(condExpr) == NativeType.I32
     ) {
       return getConstValueI32(condExpr)
-        ? this.compileExpressionRetainType(ifThen, contextualType)
+        ? this.compileExpression(ifThen, contextualType)
-        : this.compileExpressionRetainType(ifElse, contextualType);
+        : this.compileExpression(ifElse, contextualType);
     }
 
     var ifThenFlow = outerFlow.fork();
     this.currentFlow = ifThenFlow;
-    var ifThenExpr = this.compileExpressionRetainType(ifThen, contextualType, contextualFlags & ContextualFlags.SKIP_AUTORELEASE);
+    var ifThenExpr = this.compileExpression(ifThen, contextualType, contextualFlags & ContextualFlags.SKIP_AUTORELEASE);
     var ifThenType = this.currentType;
     var IfThenAutoreleaseSkipped = this.skippedAutoreleases.has(ifThenExpr);
 
     var ifElseFlow = outerFlow.fork();
     this.currentFlow = ifElseFlow;
-    var ifElseExpr = this.compileExpressionRetainType(ifElse, contextualType, contextualFlags & ContextualFlags.SKIP_AUTORELEASE);
+    var ifElseExpr = this.compileExpression(ifElse, contextualType, contextualFlags & ContextualFlags.SKIP_AUTORELEASE);
     var ifElseType = this.currentType;
     var ifElseAutoreleaseSkipped = this.skippedAutoreleases.has(ifElseExpr);
 
@@ -8133,9 +8084,7 @@ export class Compiler extends DiagnosticEmitter {
     // make a getter for the expression (also obtains the type)
     var getValue = this.compileExpression( // reports
       expression.operand,
-      contextualType == Type.void
+      contextualType.exceptVoid,
-        ? Type.i32
-        : contextualType,
       ContextualFlags.NONE
     );
 
@@ -8367,9 +8316,7 @@ export class Compiler extends DiagnosticEmitter {
       case Token.PLUS: {
         expr = this.compileExpression(
           expression.operand,
-          contextualType == Type.void
+          contextualType.exceptVoid,
-            ? Type.i32
-            : contextualType,
           ContextualFlags.NONE
         );
 
@@ -8407,9 +8354,7 @@ export class Compiler extends DiagnosticEmitter {
 
         expr = this.compileExpression(
           expression.operand,
-          contextualType == Type.void
+          contextualType.exceptVoid,
-            ? Type.i32
-            : contextualType,
           ContextualFlags.NONE
         );
 
@@ -8476,9 +8421,7 @@ export class Compiler extends DiagnosticEmitter {
         compound = true;
         expr = this.compileExpression(
           expression.operand,
-          contextualType == Type.void
+          contextualType.exceptVoid,
-            ? Type.i32
-            : contextualType,
           ContextualFlags.NONE
         );
 
@@ -8545,9 +8488,7 @@ export class Compiler extends DiagnosticEmitter {
         compound = true;
         expr = this.compileExpression(
           expression.operand,
-          contextualType == Type.void
+          contextualType.exceptVoid,
-            ? Type.i32
-            : contextualType,
           ContextualFlags.NONE
         );
 
@@ -8613,9 +8554,7 @@ export class Compiler extends DiagnosticEmitter {
       case Token.EXCLAMATION: {
         expr = this.compileExpression(
           expression.operand,
-          contextualType == Type.void
+          contextualType.exceptVoid,
-            ? Type.i32
-            : contextualType,
           ContextualFlags.NONE
         );
 

src/diagnostics.ts

@@ -280,8 +280,8 @@ export abstract class DiagnosticEmitter {
     var message = DiagnosticMessage.create(code, category, arg0, arg1, arg2).withRange(range);
     if (relatedRange) message.relatedRange = relatedRange;
     this.diagnostics.push(message);
-    // console.log(formatDiagnosticMessage(message, true, true) + "\n"); // temporary
+    console.log(formatDiagnosticMessage(message, true, true) + "\n"); // temporary
-    // console.log(<string>new Error("stack").stack);
+    console.log(<string>new Error("stack").stack);
   }
 
   /** Emits an informatory diagnostic message. */

src/types.ts

@@ -145,6 +145,12 @@ export class Type {
     }
   }
 
+  /** Substitutes this type with the auto type if this type is void. */
+  get exceptVoid(): Type {
+    if (this.kind == TypeKind.VOID) return Type.auto;
+    return this;
+  }
+
   /** Gets this type's logarithmic alignment in memory. */
   get alignLog2(): i32 {
     return 31 - clz<i32>(this.byteSize);
@@ -526,6 +532,9 @@ export class Type {
 
   /** No return type. */
   static readonly void: Type = new Type(TypeKind.VOID, TypeFlags.NONE, 0);
+
+  /** Alias of i32 indicating type inference of locals and globals with just an initializer. */
+  static readonly auto: Type = new Type(Type.i32.kind, Type.i32.flags, Type.i32.size);
 }
 
 /** Converts an array of types to an array of native types. */

tests/compiler/assert-nonnull.optimized.wat

@@ -116,6 +116,12 @@
  (func $assert-nonnull/testElem (; 8 ;) (type $FUNCSIG$ii) (param $0 i32) (result i32)
   local.get $0
   call $~lib/array/Array<assert-nonnull/Foo | null>#__get
+  local.tee $0
+  i32.eqz
+  if
+   unreachable
+  end
+  local.get $0
  )
  (func $assert-nonnull/testAll (; 9 ;) (type $FUNCSIG$ii) (param $0 i32) (result i32)
   local.get $0

tests/compiler/assert-nonnull.untouched.wat

@@ -179,7 +179,6 @@
  )
  (func $assert-nonnull/testElem (; 11 ;) (type $FUNCSIG$ii) (param $0 i32) (result i32)
   (local $1 i32)
-  (local $2 i32)
   local.get $0
   call $~lib/rt/stub/__retain
   drop
@@ -187,13 +186,16 @@
   i32.const 0
   call $~lib/array/Array<assert-nonnull/Foo | null>#__get
   local.tee $1
+  if (result i32)
+   local.get $1
+  else   
+   unreachable
+  end
   call $~lib/rt/stub/__retain
-  local.set $2
+  local.set $1
-  local.get $1
-  call $~lib/rt/stub/__release
   local.get $0
   call $~lib/rt/stub/__release
-  local.get $2
+  local.get $1
  )
  (func $assert-nonnull/testAll (; 12 ;) (type $FUNCSIG$ii) (param $0 i32) (result i32)
   (local $1 i32)

tests/compiler/retain-i32.optimized.wat

@@ -6,6 +6,7 @@
  (data (i32.const 8) "\1a\00\00\00\01\00\00\00\01\00\00\00\1a\00\00\00r\00e\00t\00a\00i\00n\00-\00i\003\002\00.\00t\00s")
  (global $retain-i32/si (mut i32) (i32.const 0))
  (global $retain-i32/ui (mut i32) (i32.const 0))
+ (global $retain-i32/ri (mut i32) (i32.const 0))
  (export "memory" (memory $0))
  (start $start)
  (func $start:retain-i32 (; 1 ;) (type $FUNCSIG$v)
@@ -254,6 +255,12 @@
    call $~lib/builtins/abort
    unreachable
   end
+  i32.const 0
+  i32.load8_s
+  global.set $retain-i32/ri
+  i32.const 0
+  i32.load8_s
+  drop
  )
  (func $start (; 2 ;) (type $FUNCSIG$v)
   call $start:retain-i32

tests/compiler/retain-i32.ts

@@ -129,3 +129,14 @@ assert(ui == 1);
 
 ui = 255 % 255;
 assert(ui == 0);
+
+// inferring global type from load should still retain T
+var ri = load<i8>(0);
+assert(ri instanceof i8);
+
+// inferring local type from load should still retain T
+function testLocalRetain(): void {
+  var ri = load<i8>(0);
+  assert(ri instanceof i8);
+}
+testLocalRetain();

tests/compiler/retain-i32.untouched.wat

@@ -18,6 +18,7 @@
  (global $~lib/builtins/u32.MAX_VALUE i32 (i32.const -1))
  (global $retain-i32/si (mut i32) (i32.const 0))
  (global $retain-i32/ui (mut i32) (i32.const 0))
+ (global $retain-i32/ri (mut i32) (i32.const 0))
  (export "memory" (memory $0))
  (start $start)
  (func $retain-i32/test (; 1 ;) (type $FUNCSIG$vii) (param $0 i32) (param $1 i32)
@@ -330,7 +331,25 @@
    unreachable
   end
  )
- (func $start:retain-i32 (; 2 ;) (type $FUNCSIG$v)
+ (func $retain-i32/testLocalRetain (; 2 ;) (type $FUNCSIG$v)
+  (local $0 i32)
+  i32.const 0
+  i32.load8_s
+  local.set $0
+  local.get $0
+  drop
+  i32.const 1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 140
+   i32.const 2
+   call $~lib/builtins/abort
+   unreachable
+  end
+ )
+ (func $start:retain-i32 (; 3 ;) (type $FUNCSIG$v)
   (local $0 i32)
   i32.const 0
   global.get $~lib/builtins/i8.MAX_VALUE
@@ -786,10 +805,26 @@
    call $~lib/builtins/abort
    unreachable
   end
+  i32.const 0
+  i32.load8_s
+  global.set $retain-i32/ri
+  global.get $retain-i32/ri
+  drop
+  i32.const 1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 135
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  call $retain-i32/testLocalRetain
  )
- (func $start (; 3 ;) (type $FUNCSIG$v)
+ (func $start (; 4 ;) (type $FUNCSIG$v)
   call $start:retain-i32
  )
- (func $null (; 4 ;) (type $FUNCSIG$v)
+ (func $null (; 5 ;) (type $FUNCSIG$v)
  )
 )

tests/compiler/std/symbol.optimized.wat

@@ -1475,6 +1475,7 @@
   call $~lib/string/String.__concat
  )
  (func $start:std/symbol (; 27 ;) (type $FUNCSIG$v)
+  (local $0 i32)
   i32.const 24
   call $~lib/symbol/Symbol
   global.set $std/symbol/sym1
@@ -1537,9 +1538,21 @@
   end
   global.get $std/symbol/sym3
   call $~lib/symbol/_Symbol.keyFor
+  local.tee $0
+  i32.eqz
+  if
+   unreachable
+  end
+  local.get $0
   global.set $std/symbol/key3
   global.get $std/symbol/sym4
   call $~lib/symbol/_Symbol.keyFor
+  local.tee $0
+  i32.eqz
+  if
+   unreachable
+  end
+  local.get $0
   global.set $std/symbol/key4
   global.get $std/symbol/key3
   i32.const 24

tests/compiler/std/symbol.untouched.wat

@@ -3342,8 +3342,6 @@
   (local $1 i32)
   (local $2 i32)
   (local $3 i32)
-  (local $4 i32)
-  (local $5 i32)
   i32.const 24
   call $~lib/symbol/Symbol
   global.set $std/symbol/sym1
@@ -3423,11 +3421,21 @@
   global.get $std/symbol/sym3
   call $~lib/symbol/_Symbol.keyFor
   local.tee $0
+  if (result i32)
+   local.get $0
+  else   
+   unreachable
+  end
   call $~lib/rt/stub/__retain
   global.set $std/symbol/key3
   global.get $std/symbol/sym4
   call $~lib/symbol/_Symbol.keyFor
-  local.tee $1
+  local.tee $0
+  if (result i32)
+   local.get $0
+  else   
+   unreachable
+  end
   call $~lib/rt/stub/__retain
   global.set $std/symbol/key4
   global.get $std/symbol/key3
@@ -3457,7 +3465,7 @@
   i32.const 0
   call $~lib/symbol/Symbol
   call $~lib/symbol/_Symbol#toString
-  local.tee $2
+  local.tee $0
   i32.const 704
   call $~lib/string/String.__eq
   i32.eqz
@@ -3471,7 +3479,7 @@
   end
   global.get $std/symbol/sym3
   call $~lib/symbol/_Symbol#toString
-  local.tee $3
+  local.tee $1
   i32.const 736
   call $~lib/string/String.__eq
   i32.eqz
@@ -3489,7 +3497,7 @@
   global.set $std/symbol/isConcatSpreadable
   global.get $std/symbol/hasInstance
   call $~lib/symbol/_Symbol#toString
-  local.tee $4
+  local.tee $2
   i32.const 776
   call $~lib/string/String.__eq
   i32.eqz
@@ -3503,7 +3511,7 @@
   end
   global.get $std/symbol/isConcatSpreadable
   call $~lib/symbol/_Symbol#toString
-  local.tee $5
+  local.tee $3
   i32.const 832
   call $~lib/string/String.__eq
   i32.eqz
@@ -3527,10 +3535,6 @@
   call $~lib/rt/stub/__release
   local.get $3
   call $~lib/rt/stub/__release
-  local.get $4
-  call $~lib/rt/stub/__release
-  local.get $5
-  call $~lib/rt/stub/__release
  )
  (func $start (; 34 ;) (type $FUNCSIG$v)
   call $start:std/symbol