diff --git a/ql/src/codeql_ql/ast/Ast.qll b/ql/src/codeql_ql/ast/Ast.qll
index 7921c6c441b..73622380526 100644
--- a/ql/src/codeql_ql/ast/Ast.qll
+++ b/ql/src/codeql_ql/ast/Ast.qll
@@ -283,6 +283,8 @@ class CharPred extends TCharPred, Predicate {
     or
     pred_name = directMember("getBody") and result = this.getBody()
   }
+
+  ClassType getDeclaringType() { result.getDeclaration() = getParent() }
 }
 
 /**
@@ -600,7 +602,7 @@ class Call extends TCall, Expr {
     none() // overriden in sublcasses.
   }
 
-  Predicate getTarget() { resolveCall(this, result) }
+  PredicateOrBuiltin getTarget() { resolveCall(this, result) }
 
   override Type getType() { result = this.getTarget().getReturnType() }
 
diff --git a/ql/src/codeql_ql/ast/internal/Builtins.qll b/ql/src/codeql_ql/ast/internal/Builtins.qll
new file mode 100644
index 00000000000..1f9638ed63c
--- /dev/null
+++ b/ql/src/codeql_ql/ast/internal/Builtins.qll
@@ -0,0 +1,60 @@
+predicate isBuiltinClassless(string sig) {
+  sig =
+    [
+      "predicate any()", "predicate none()", "predicate toUrl(string, int, int, int, string)",
+      "predicate toUrl(string, int, int, int, int, string)"
+    ]
+}
+
+predicate isBuiltinClassless(string ret, string name, string args) {
+  exists(string sig, string re | re = "(\\w+) (\\w+)\\(([\\w, ]*)\\)" |
+    isBuiltinClassless(sig) and
+    ret = sig.regexpCapture(re, 1) and
+    name = sig.regexpCapture(re, 2) and
+    args = sig.regexpCapture(re, 3)
+  )
+}
+
+predicate isBuiltinMember(string sig) {
+  sig =
+    [
+      "boolean boolean.booleanAnd(boolean)", "boolean boolean.booleanOr(boolean)",
+      "boolean boolean.booleanXor(boolean)", "boolean boolean.booleanNot()",
+      "string boolean.toString()", "float float.abs()", "float float.acos()", "float float.atan()",
+      "int float.ceil()", "float float.copySign(float)", "float float.cos()", "float float.cosh()",
+      "float float.exp()", "int float.floor()", "float float.log()", "float float.log(float)",
+      "float float.log2()", "float float.log10()", "float float.maximum(float)",
+      "float float.minimum(float)", "float float.nextAfter(float)", "float float.nextDown()",
+      "float float.nextUp()", "float float.pow(float)", "float float.signum()", "float float.sin()",
+      "float float.sinh()", "float float.sqrt()", "float float.tan()", "float float.tanh()",
+      "string float.toString()", "float float.ulp()", "int int.abs()", "int int.bitAnd(int)",
+      "int int.bitOr(int)", "int int.bitNot()", "int int.bitXor(int)", "int int.bitShiftLeft(int)",
+      "int int.bitShiftRight(int)", "int int.bitShiftRightSigned(int)", "int int.gcd(int)",
+      "string int.toString()", "string string.charAt(int)", "int string.indexOf(string)",
+      "int string.indexOf(string, int, int)", "predicate string.isLowercase()",
+      "predicate string.isUppercase()", "int string.length()", "predicate string.matches(string)",
+      "string string.prefix(int)", "string regexpCapture(string, int)",
+      "string regexpFind(string, int, int)", "predicate string.regexpMatch(string)",
+      "string string.regexpReplaceAll(string, string)", "string string.replaceAll(string, string)",
+      "string string.splitAt(string)", "string string.splitAt(string, int)",
+      "string string.substring(int, int)", "string string.suffix(int)", "date string.toDate()",
+      "float string.toFloat()", "int string.toInt()", "string string.toString()",
+      "string string.toLowerCase()", "string string.toUpperCase()", "string string.trim()",
+      "int date.daysTo(date)", "int date.getDay()", "int date.getHours()", "int date.getMinutes()",
+      "int date.getMonth()", "int date.getSeconds()", "int date.getYear()",
+      "string date.toString()", "string date.toISO()"
+    ]
+}
+
+predicate isBuiltinMember(string qual, string ret, string name, string args) {
+  exists(string sig, string re | re = "(\\w+) (\\w+)\\.(\\w+)\\(([\\w, ]*)\\)" |
+    isBuiltinMember(sig) and
+    ret = sig.regexpCapture(re, 1) and
+    qual = sig.regexpCapture(re, 2) and
+    name = sig.regexpCapture(re, 3) and
+    args = sig.regexpCapture(re, 4)
+  )
+}
+
+bindingset[args]
+string getArgType(string args, int i) { result = args.splitAt(",", i).trim() }
diff --git a/ql/src/codeql_ql/ast/internal/Predicate.qll b/ql/src/codeql_ql/ast/internal/Predicate.qll
index 2c71e09f46e..bdce9a97cda 100644
--- a/ql/src/codeql_ql/ast/internal/Predicate.qll
+++ b/ql/src/codeql_ql/ast/internal/Predicate.qll
@@ -1,4 +1,5 @@
 import ql
+private import Builtins
 private import codeql_ql.ast.internal.Module
 
 private predicate definesPredicate(FileOrModule m, string name, ClasslessPredicate p, boolean public) {
@@ -38,7 +39,7 @@ predicate resolvePredicateExpr(PredicateExpr pe, ClasslessPredicate p) {
   )
 }
 
-private predicate resolvePredicateCall(PredicateCall pc, Predicate p) {
+private predicate resolvePredicateCall(PredicateCall pc, PredicateOrBuiltin p) {
   exists(Class c, ClassType t |
     c = pc.getParent*() and
     t = c.getType() and
@@ -53,24 +54,125 @@ private predicate resolvePredicateCall(PredicateCall pc, Predicate p) {
     m = pc.getQualifier().getResolvedModule() and
     public = true
   |
-    definesPredicate(m, pc.getPredicateName(), p, public) and
-    count(p.getParameter(_)) = pc.getNumberOfArguments()
+    definesPredicate(m, pc.getPredicateName(), p.getDeclaration(), public) and
+    p.getArity() = pc.getNumberOfArguments()
   )
 }
 
-private predicate resolveMemberCall(MemberCall mc, Predicate p) {
-  exists(ClassType t |
+private predicate resolveMemberCall(MemberCall mc, PredicateOrBuiltin p) {
+  exists(Type t |
     t = mc.getBase().getType() and
     p = t.getClassPredicate(mc.getMemberName(), mc.getNumberOfArguments())
   )
 }
 
-predicate resolveCall(Call c, Predicate p) {
+predicate resolveCall(Call c, PredicateOrBuiltin p) {
   resolvePredicateCall(c, p)
   or
   resolveMemberCall(c, p)
 }
 
+private newtype TPredOrBuiltin =
+  TPred(Predicate p) or
+  TBuiltinClassless(string ret, string name, string args) { isBuiltinClassless(ret, name, args) } or
+  TBuiltinMember(string qual, string ret, string name, string args) {
+    isBuiltinMember(qual, ret, name, args)
+  }
+
+class PredicateOrBuiltin extends TPredOrBuiltin {
+  string getName() { none() }
+
+  string toString() { result = getName() }
+
+  predicate hasLocationInfo(
+    string filepath, int startline, int startcolumn, int endline, int endcolumn
+  ) {
+    if exists(getDeclaration())
+    then
+      getDeclaration()
+          .getLocation()
+          .hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
+    else (
+      filepath = "" and
+      startline = 0 and
+      startcolumn = 0 and
+      endline = 0 and
+      endcolumn = 0
+    )
+  }
+
+  Predicate getDeclaration() { none() }
+
+  Type getDeclaringType() { none() }
+
+  Type getParameterType(int i) { none() }
+
+  Type getReturnType() { none() }
+
+  int getArity() { result = count(getParameterType(_)) }
+
+  predicate isPrivate() { none() }
+}
+
+private class DefinedPredicate extends PredicateOrBuiltin, TPred {
+  Predicate decl;
+
+  DefinedPredicate() { this = TPred(decl) }
+
+  override Predicate getDeclaration() { result = decl }
+
+  override string getName() { result = decl.getName() }
+
+  override Type getReturnType() { result = decl.getReturnType() }
+
+  override Type getParameterType(int i) { result = decl.getParameter(i).getType() }
+
+  override Type getDeclaringType() {
+    result = decl.(ClassPredicate).getDeclaringType()
+    or
+    result = decl.(CharPred).getDeclaringType()
+  }
+
+  override predicate isPrivate() {
+    decl.(ClassPredicate).isPrivate() or decl.(ClassPredicate).isPrivate()
+  }
+}
+
+private class TBuiltin = TBuiltinClassless or TBuiltinMember;
+
+class BuiltinPredicate extends PredicateOrBuiltin, TBuiltin { }
+
+private class BuiltinClassless extends BuiltinPredicate, TBuiltinClassless {
+  string name;
+  string ret;
+  string args;
+
+  BuiltinClassless() { this = TBuiltinClassless(ret, name, args) }
+
+  override string getName() { result = name }
+
+  override PrimitiveType getReturnType() { result.getName() = ret }
+
+  override PrimitiveType getParameterType(int i) { result.getName() = getArgType(args, i) }
+}
+
+private class BuiltinMember extends BuiltinPredicate, TBuiltinMember {
+  string name;
+  string qual;
+  string ret;
+  string args;
+
+  BuiltinMember() { this = TBuiltinMember(qual, ret, name, args) }
+
+  override string getName() { result = name }
+
+  override PrimitiveType getReturnType() { result.getName() = ret }
+
+  override PrimitiveType getParameterType(int i) { result.getName() = getArgType(args, i) }
+
+  override PrimitiveType getDeclaringType() { result.getName() = qual }
+}
+
 module PredConsistency {
   query predicate noResolvePredicateExpr(PredicateExpr pe) {
     not resolvePredicateExpr(pe, _) and
@@ -88,8 +190,8 @@ module PredConsistency {
     resolvePredicateExpr(pe, p)
   }
 
-  query predicate multipleResolveCall(Call call, int c, Predicate p) {
-    c = strictcount(Predicate p0 | resolveCall(call, p0)) and
+  query predicate multipleResolveCall(Call call, int c, PredicateOrBuiltin p) {
+    c = strictcount(PredicateOrBuiltin p0 | resolveCall(call, p0)) and
     c > 1 and
     resolveCall(call, p)
   }
diff --git a/ql/src/codeql_ql/ast/internal/Type.qll b/ql/src/codeql_ql/ast/internal/Type.qll
index 33538a91a80..63a837545cd 100644
--- a/ql/src/codeql_ql/ast/internal/Type.qll
+++ b/ql/src/codeql_ql/ast/internal/Type.qll
@@ -2,6 +2,7 @@ import ql
 private import codeql_ql.ast.internal.AstNodes as AstNodes
 private import codeql_ql.ast.internal.TreeSitter
 private import codeql_ql.ast.internal.Module
+private import codeql_ql.ast.internal.Predicate
 
 private newtype TType =
   TClass(Class c) { isActualClass(c) } or
@@ -59,6 +60,13 @@ class Type extends TType {
       endcolumn = 0
     )
   }
+
+  PredicateOrBuiltin getClassPredicate(string name, int arity) {
+    result = classPredCandidate(this, name, arity) and
+    not exists(PredicateOrBuiltin other | other = classPredCandidate(this, name, arity) |
+      other.getDeclaringType().getASuperType+() = result.getDeclaringType()
+    )
+  }
 }
 
 class ClassType extends Type, TClass {
@@ -78,13 +86,6 @@ class ClassType extends Type, TClass {
     result = super.getAnInternalSuperType()
   }
 
-  ClassPredicate getClassPredicate(string name, int arity) {
-    result = classPredCandidate(this, name, arity) and
-    not exists(ClassPredicate other | other = classPredCandidate(this, name, arity) |
-      other.getDeclaringType().getASuperType+() = result.getDeclaringType()
-    )
-  }
-
   VarDecl getField(string name) {
     result = fieldCandidate(this, name) and
     not exists(VarDecl other | other = fieldCandidate(this, name) |
@@ -93,26 +94,27 @@ class ClassType extends Type, TClass {
   }
 }
 
-private ClassPredicate declaredPred(ClassType ty, string name, int arity) {
-  result = ty.getDeclaration().getAClassPredicate() and
+private PredicateOrBuiltin declaredPred(Type ty, string name, int arity) {
+  result.getDeclaringType() = ty and
   result.getName() = name and
   result.getArity() = arity
 }
 
-private ClassPredicate classPredCandidate(ClassType ty, string name, int arity) {
+private PredicateOrBuiltin classPredCandidate(Type ty, string name, int arity) {
   result = declaredPred(ty, name, arity)
   or
   not exists(declaredPred(ty, name, arity)) and
   result = inherClassPredCandidate(ty, name, arity)
 }
 
-private ClassPredicate inherClassPredCandidate(ClassType ty, string name, int arity) {
-  result = classPredCandidate(ty.getASuperType(), name, arity) and
+private PredicateOrBuiltin inherClassPredCandidate(Type ty, string name, int arity) {
+  result = classPredCandidate(ty.getAnInternalSuperType(), name, arity) and
   not result.isPrivate()
 }
 
 predicate predOverrides(ClassPredicate sub, ClassPredicate sup) {
-  sup = inherClassPredCandidate(sub.getDeclaringType(), sub.getName(), sub.getArity())
+  sup =
+    inherClassPredCandidate(sub.getDeclaringType(), sub.getName(), sub.getArity()).getDeclaration()
 }
 
 private VarDecl declaredField(ClassType ty, string name) {
@@ -322,7 +324,7 @@ module TyConsistency {
 
   query predicate exprNoType(Expr e) {
     not exists(e.getType()) and
-    not exists(Predicate p |
+    not exists(PredicateOrBuiltin p |
       p = e.(Call).getTarget() and
       not exists(p.getReturnType())
     ) and
diff --git a/ql/src/ide-contextual-queries/Definitions.qll b/ql/src/ide-contextual-queries/Definitions.qll
index 2864ae5fca6..deb977fe672 100644
--- a/ql/src/ide-contextual-queries/Definitions.qll
+++ b/ql/src/ide-contextual-queries/Definitions.qll
@@ -49,7 +49,7 @@ private predicate resolveVar(VarAccess va, VarDecl decl, string kind) {
 }
 
 private predicate resolveCall(Call c, Predicate p, string kind) {
-  p = c.getTarget() and
+  p = c.getTarget().getDeclaration() and
   kind = "call"
 }