Various fixes to matchImpl. Variables can now shadow functions, but not other variables

src/frontend/compiler.nim

@@ -574,7 +574,9 @@ proc inferType(self: Compiler, node: Expression): Type =
             if name != nil:
                 return name.valueType
             else:
-                return node.name.lexeme.toIntrinsic()
+                result = node.name.lexeme.toIntrinsic()
+                if result != nil:
+                    result.node = node
         of unaryExpr:
             return self.inferType(UnaryExpr(node).a)
         of binaryExpr:
@@ -608,14 +610,14 @@ proc typeToStr(self: Compiler, typ: Type): string =
                 of funDecl:
                     var node = FunDecl(typ.node)
                     for i, argument in node.arguments:
-                        result &= &"{argument.name.token.lexeme}: {self.typeToStr(self.inferType(argument.name))}"
+                        result &= &"{argument.name.token.lexeme}: {self.typeToStr(self.inferType(argument.valueType))}"
                         if i < node.arguments.len() - 1:
                             result &= ", "
                     result &= ")"
                 of lambdaExpr:
                     var node = LambdaExpr(typ.node)
                     for i, argument in node.arguments:
-                        result &= &"{argument.name.token.lexeme}: {argument.valueType}"
+                        result &= &"{argument.name.token.lexeme}: {self.typeToStr(self.inferType(argument.name))}"
                         if i < node.arguments.len() - 1:
                             result &= ", "
                     result &= ")"
@@ -735,16 +737,25 @@ proc matchImpl(self: Compiler, name: string, kind: Type): Name =
     ## Tries to find a matching function implementation
     ## compatible with the given type and returns its
     ## name object
-
     let impl = self.findByType(name, kind)
     if impl.len() == 0:
         var msg = &"cannot find a suitable implementation for '{name}'"
         let names = self.findByName(name)
         if names.len() > 0:
-            msg &= &", found {len(names)} candidates:"
+            msg &= &", found {len(names)} candidate"
+            if names.len() > 1:
+                msg &= "s"
+            msg &= ": "
             for name in names:
-                echo name[]
-                msg &= &"- '{name.name.token.lexeme}' of type {self.typeToStr(name.valueType)}\n"
+                msg &= &"\n - '{name.name.token.lexeme}' of type '{self.typeToStr(name.valueType)}'"
+                if name.valueType.kind != Function:
+                    msg &= ", not a callable"
+                elif kind.args.len() != name.valueType.args.len():
+                    msg &= &", wrong number of arguments ({name.valueType.args.len()} expected, got {kind.args.len()})\n"
+                else:
+                    for i, arg in kind.args:
+                        if not self.compareTypes(arg, name.valueType.args[i]):
+                            msg &= &", first mismatch at position {i + 1}: expected argument of type '{self.typeToStr(name.valueType.args[i])}', got '{self.typeToStr(arg)}' instead"
         self.error(msg)
     elif impl.len() > 1:
         var msg = &"multiple matching implementations of '{name}' found:\n"
@@ -752,6 +763,7 @@ proc matchImpl(self: Compiler, name: string, kind: Type): Name =
             var node = FunDecl(fn.valueType.node)
             msg &= &"- '{node.name.token.lexeme}' at line {node.token.line} of type {self.typeToStr(fn.valueType)}\n"
         self.error(msg)
+    return impl[0]
 
 
 proc callUnaryOp(self: Compiler, fn: Name, op: UnaryExpr) =
@@ -839,7 +851,7 @@ proc declareName(self: Compiler, node: Declaration) =
                 # slap myself 100 times with a sign saying "I'm dumb". Mark my words
                 self.error("cannot declare more than 16777216 variables at a time")
             for name in self.findByName(node.name.token.lexeme):
-                if name.name.token.lexeme == node.name.token.lexeme:
+                if name.name.token.lexeme == node.name.token.lexeme and name.depth == self.scopeDepth and name.valueType.node.kind == varDecl:
                     self.error(&"attempt to redeclare '{node.name.token.lexeme}', which was previously defined in '{name.owner}' at line {name.valueType.node.token.line}")
             self.names.add(Name(depth: self.scopeDepth,
                                 name: node.name,
@@ -1276,11 +1288,11 @@ proc statement(self: Compiler, node: Statement) =
 
 proc varDecl(self: Compiler, node: VarDecl) =
     ## Compiles variable declarations
-    let kind = self.toIntrinsic(node.valueType)
+    let kind = self.inferType(node.valueType)
     let typ = self.inferType(node.value)
     if kind == nil and typ == nil:
         self.error(&"cannot determine the type of '{node.name.token.lexeme}'")
-    elif typ != kind and kind != nil:
+    elif not self.compareTypes(typ, kind):
         self.error(&"expected value of type '{self.typeToStr(kind)}', but '{node.name.token.lexeme}' is of type '{self.typeToStr(typ)}'")
     self.expression(node.value)
     self.declareName(node)

src/tests.pn

@@ -2,4 +2,11 @@ operator `+`(a: int): int {
     return a;
 }
 
+operator `+`(a: int32): int32 {
+    return a;
+}
+
+var `+`: int = 1;  # hehehehe
+
 +1;  # Works: defined for int64
++1'u8; # Nope!