fix(checker): reduce error noise (#285)

lib/bait/checker/assign.bt

@@ -7,15 +7,9 @@ import bait.context
 import bait.token
 
 fun (mut c Checker) decl_assign(mut node ast.AssignStmt) {
-	typ := c.non_void_expr(node.right) or {
-		return
-	}
-
-	// Type info must be set for BlankIdent as well due to backend limitations
-	node.left_type = typ
-	node.right_type = typ
-
 	if node.left is ast.BlankIdent {
+		// Note: Side types must be set for BlankIdent due to backend limitations
+		_ = c.decl_right_side(mut node)
 		return
 	}
 
@@ -32,7 +26,7 @@ fun (mut c Checker) decl_assign(mut node ast.AssignStmt) {
 		msg := if obj.kind == .package_ {
 			'cannot shadow import "${left.name}"'
 		} else {
-			'redefinition of ${left.name}'
+			"redefinition of `${left.name}`"
 		}
 		c.error(msg, node.pos)
 		return
@@ -44,6 +38,8 @@ fun (mut c Checker) decl_assign(mut node ast.AssignStmt) {
 		return
 	}
 
+	typ := c.decl_right_side(mut node)
+
 	// Register identifier
 	c.scope.register(left.name, context.ScopeObject{
 		kind = .variable
@@ -53,6 +49,17 @@ fun (mut c Checker) decl_assign(mut node ast.AssignStmt) {
 	_ = c.expr(node.left)
 }
 
+fun (mut c Checker) decl_right_side(mut node ast.AssignStmt) ast.Type {
+	typ := c.non_void_expr(node.right) or {
+		return ast.ERROR_TYPE
+	}
+
+	node.left_type = typ
+	node.right_type = typ
+
+	return typ
+}
+
 fun (mut c Checker) assign_stmt(mut node ast.AssignStmt) {
 	if node.op == .decl_assign {
 		c.decl_assign(mut node)

lib/bait/checker/if_match.bt

@@ -74,6 +74,10 @@ fun (mut c Checker) if_match(mut node ast.IfMatch) ast.Type {
 			last_type := c.stmts_with_return(branch.stmts)
 			c.close_scope()
 
+			if last_type == ast.ERROR_TYPE {
+				continue
+			}
+
 			last := branch.stmts.last()
 			if is_noreturn(last) {
 				continue

lib/bait/checker/index.bt

@@ -39,6 +39,10 @@ fun (mut c Checker) index_expr(mut node ast.IndexExpr) ast.Type {
 	}
 
 	if sym.kind == .map {
+		if idx_type == ast.ERROR_TYPE {
+			return ast.ERROR_TYPE
+		}
+
 		info := sym.info as ast.MapInfo
 		if idx_type != info.key_type {
 			c.error("invalid map index `${c.table.type_name(idx_type)}`, expected `${c.table.type_name(info.key_type)}`", node.pos)
@@ -83,6 +87,10 @@ fun (mut c Checker) range_expr(node ast.RangeExpr) ast.Type {
 }
 
 fun (mut c Checker) check_int_index(typ ast.Type, pos token.Pos) {
+	if typ == ast.ERROR_TYPE {
+		return
+	}
+
 	if not c.check_types(typ, ast.I32_TYPE) {
 		c.error("non-integer index `${c.table.type_name(typ)}`", pos)
 	}

tests/out/error/assign/twice_ident.in.bt

@@ -0,0 +1,2 @@
+a := 1
+a := b

tests/out/error/assign/twice_ident.out

@@ -0,0 +1 @@
+tests/out/error/assign/twice_ident.in.bt:2:1 error: redefinition of `a`

tests/out/error/fun/param_redefine.out

@@ -1,2 +1,2 @@
-tests/out/error/fun/param_redefine.in.bt:2:2 error: redefinition of p
+tests/out/error/fun/param_redefine.in.bt:2:2 error: redefinition of `p`
 tests/out/error/fun/param_redefine.in.bt:5:16 error: redefinition of a

tests/out/error/ident/redef.out

@@ -1,3 +1,3 @@
-tests/out/error/ident/redef.in.bt:3:2 error: redefinition of same
-tests/out/error/ident/redef.in.bt:6:3 error: redefinition of same
-tests/out/error/ident/redef.in.bt:11:2 error: redefinition of my_fun
+tests/out/error/ident/redef.in.bt:3:2 error: redefinition of `same`
+tests/out/error/ident/redef.in.bt:6:3 error: redefinition of `same`
+tests/out/error/ident/redef.in.bt:11:2 error: redefinition of `my_fun`

tests/out/error/index/invalid_index.in.bt

@@ -3,15 +3,18 @@ _ = arr[0]
 _ = arr[true]
 _ = arr[1.0]
 _ = arr["hi"]
+_ = arr[badvar]
 
 s := "hello"
 _ = s[0]
 _ = s[arr]
 _ = s[`x`]
+_ = s[badvar]
 
 mymap := map{
 	"a": 1
 }
 _ = mymap["b"]
 _ = mymap[0]
 _ = mymap[s]
+_ = mymap[badvar]

tests/out/error/index/invalid_index.out

@@ -1,6 +1,9 @@
 tests/out/error/index/invalid_index.in.bt:3:8 error: non-integer index `bool`
 tests/out/error/index/invalid_index.in.bt:4:8 error: non-integer index `f64`
 tests/out/error/index/invalid_index.in.bt:5:8 error: non-integer index `string`
-tests/out/error/index/invalid_index.in.bt:9:6 error: non-integer index `[]i32`
-tests/out/error/index/invalid_index.in.bt:10:6 error: non-integer index `u8`
-tests/out/error/index/invalid_index.in.bt:16:10 error: invalid map index `i32`, expected `string`
+tests/out/error/index/invalid_index.in.bt:6:9 error: undefined ident `badvar`
+tests/out/error/index/invalid_index.in.bt:10:6 error: non-integer index `[]i32`
+tests/out/error/index/invalid_index.in.bt:11:6 error: non-integer index `u8`
+tests/out/error/index/invalid_index.in.bt:12:7 error: undefined ident `badvar`
+tests/out/error/index/invalid_index.in.bt:18:10 error: invalid map index `i32`, expected `string`
+tests/out/error/index/invalid_index.in.bt:20:11 error: undefined ident `badvar`