null checking throughout logical and/or

src/compiler.ts

@@ -4755,8 +4755,14 @@ export class Compiler extends DiagnosticEmitter {
       case Token.AMPERSAND_AMPERSAND: { // left && right
         leftExpr = this.compileExpressionRetainType(left, contextualType, WrapMode.NONE);
         leftType = this.currentType;
+
+        let previousFlow = this.currentFlow;
+        let rightFlow = previousFlow.fork();
+        this.currentFlow = rightFlow;
+        rightFlow.inheritNonnullIf(leftExpr);
         rightExpr = this.compileExpression(right, leftType, ConversionKind.IMPLICIT, WrapMode.NONE);
         rightType = leftType;
+        this.currentFlow = previousFlow;
 
         // simplify if only interested in true or false
         if (contextualType == Type.bool || contextualType == Type.void) {
@@ -4799,8 +4805,14 @@ export class Compiler extends DiagnosticEmitter {
       case Token.BAR_BAR: { // left || right
         leftExpr = this.compileExpressionRetainType(left, contextualType, WrapMode.NONE);
         leftType = this.currentType;
+
+        let previousFlow = this.currentFlow;
+        let rightFlow = previousFlow.fork();
+        this.currentFlow = rightFlow;
+        rightFlow.inheritNonnullIfNot(leftExpr);
         rightExpr = this.compileExpression(right, leftType, ConversionKind.IMPLICIT, WrapMode.NONE);
         rightType = leftType;
+        this.currentFlow = previousFlow;
 
         // simplify if only interested in true or false
         if (contextualType == Type.bool || contextualType == Type.void) {

tests/compiler/possibly-null.optimized.wat

@@ -16,6 +16,10 @@
  (export "testWhile" (func $possibly-null/testWhile))
  (export "testWhile2" (func $possibly-null/testWhile2))
  (export "testWhile3" (func $possibly-null/testWhile3))
+ (export "testLogicalAnd" (func $possibly-null/testTrue))
+ (export "testLogicalOr" (func $possibly-null/testTrue))
+ (export "testLogicalAndMulti" (func $possibly-null/testLogicalAndMulti))
+ (export "testLogicalOrMulti" (func $possibly-null/testLogicalAndMulti))
  (func $possibly-null/testTrue (; 0 ;) (type $FUNCSIG$vi) (param $0 i32)
   nop
  )
@@ -52,7 +56,10 @@
    end
   end
  )
- (func $null (; 4 ;) (type $FUNCSIG$v)
+ (func $possibly-null/testLogicalAndMulti (; 4 ;) (type $FUNCSIG$vii) (param $0 i32) (param $1 i32)
+  nop
+ )
+ (func $null (; 5 ;) (type $FUNCSIG$v)
   nop
  )
 )

tests/compiler/possibly-null.ts

@@ -83,16 +83,30 @@ export function testWhile3(a: Ref | null, b: Ref | null): void {
   }
 }
 
-// TODO:
+function requireNonNull(a: Ref): Ref {
+  return a;
+}
 
-// function requireNonNull(a: Ref): Ref {
+export function testLogicalAnd(a: Ref | null): void {
-//   return a;
+  a && requireNonNull(a);
-// }
+}
 
-// export function testLogicalAnd(a: Ref | null): void {
+export function testLogicalOr(a: Ref | null): void {
-//   a && requireNonNull(a);
+  !a || requireNonNull(a) != null;
-// }
+}
 
-// export function testLogicalOr(a: Ref | null): void {
+export function testLogicalAndMulti(a: Ref | null, b: Ref | null): void {
-//   !a || requireNonNull(a);
+  if (a && b) {
-// }
+    if (isNullable(a)) ERROR("should be non-nullable");
+    if (isNullable(b)) ERROR("should be non-nullable");
+  }
+}
+
+export function testLogicalOrMulti(a: Ref | null, b: Ref | null): void {
+  if (!a || !b) {
+    // something
+  } else {
+    if (isNullable(a)) ERROR("should be non-nullable");
+    if (isNullable(b)) ERROR("should be non-nullable");
+  }
+}

tests/compiler/possibly-null.untouched.wat

@@ -1,6 +1,7 @@
 (module
  (type $FUNCSIG$vi (func (param i32)))
  (type $FUNCSIG$vii (func (param i32 i32)))
+ (type $FUNCSIG$ii (func (param i32) (result i32)))
  (type $FUNCSIG$v (func))
  (memory $0 0)
  (table $0 1 funcref)
@@ -18,6 +19,10 @@
  (export "testWhile" (func $possibly-null/testWhile))
  (export "testWhile2" (func $possibly-null/testWhile2))
  (export "testWhile3" (func $possibly-null/testWhile3))
+ (export "testLogicalAnd" (func $possibly-null/testLogicalAnd))
+ (export "testLogicalOr" (func $possibly-null/testLogicalOr))
+ (export "testLogicalAndMulti" (func $possibly-null/testLogicalAndMulti))
+ (export "testLogicalOrMulti" (func $possibly-null/testLogicalOrMulti))
  (func $possibly-null/testTrue (; 0 ;) (type $FUNCSIG$vi) (param $0 i32)
   local.get $0
   if
@@ -128,6 +133,58 @@
    end
   end
  )
- (func $null (; 12 ;) (type $FUNCSIG$v)
+ (func $possibly-null/requireNonNull (; 12 ;) (type $FUNCSIG$ii) (param $0 i32) (result i32)
+  local.get $0
+ )
+ (func $possibly-null/testLogicalAnd (; 13 ;) (type $FUNCSIG$vi) (param $0 i32)
+  local.get $0
+  if (result i32)
+   local.get $0
+   call $possibly-null/requireNonNull
+  else   
+   i32.const 0
+  end
+  drop
+ )
+ (func $possibly-null/testLogicalOr (; 14 ;) (type $FUNCSIG$vi) (param $0 i32)
+  local.get $0
+  i32.eqz
+  if (result i32)
+   i32.const 1
+  else   
+   local.get $0
+   call $possibly-null/requireNonNull
+   i32.const 0
+   i32.ne
+  end
+  drop
+ )
+ (func $possibly-null/testLogicalAndMulti (; 15 ;) (type $FUNCSIG$vii) (param $0 i32) (param $1 i32)
+  local.get $0
+  if (result i32)
+   local.get $1
+  else   
+   i32.const 0
+  end
+  if
+   nop
+  end
+ )
+ (func $possibly-null/testLogicalOrMulti (; 16 ;) (type $FUNCSIG$vii) (param $0 i32) (param $1 i32)
+  local.get $0
+  i32.eqz
+  if (result i32)
+   i32.const 1
+  else   
+   local.get $1
+   i32.eqz
+  end
+  if
+   nop
+  else   
+   nop
+  end
+ )
+ (func $null (; 17 ;) (type $FUNCSIG$v)
  )
 )